solar battery maintenance

[Ooops]

I know this has been asked before but my research has come up with two conflicting answers so I'm looking for clarification

My D3 has a traxide dual battery system fitted that includes a yellow top and red top Optima

Can I use a 20w unregulated solar panel for a short term emergency charge and for long term battery maintenance?

TIA

[bee utey]

You'll get around 1.2 amps maximum out of a directly connected 20W panel so it is unlikely to damage anything short term. I wouldn't leave it connected long term though without a regulator. Small regs start from around $20.

20A 12V-24V LCD Display PWM Solar Panel Regulator Charge Controller & Timer PWM | eBay (http://www.ebay.com.au/itm/20A-12V-24V-LCD-Display-PWM-Solar-Panel-Regulator-Charge-Controller-Timer-PWM-/172234127978?hash=item2819f43a6a:g:aTQAAOSwbYZXV6A r)

[Ooops]

20A 12V-24V LCD Display PWM Solar Panel Regulator Charge Controller & Timer PWM | eBay (http://www.ebay.com.au/itm/20A-12V-24V-LCD-Display-PWM-Solar-Panel-Regulator-Charge-Controller-Timer-PWM-/172234127978?hash=item2819f43a6a:g:aTQAAOSwbYZXV6A r)

Many thanks for that. Its not the cost, its that didn't happen to have a controller to hand and wanted to make sure it was safe within reason

Thanks for the link too. If they post outside of Aus I'll be ordering one

[DiscoMick]

Pretty sure Jaycar say to fit a regulator for 20 watts and above. Trickle feed solar panels often don't have a regulator. I have used a 15 watt panel as a trickle feed without problems, because the Defender seems to have a slow drain, maybe because of the trailer brake display. Regulators are dirt cheap - $20. I've got a 10A one in the Defender plus a spare one I haven't used yet. My regulator is then connected to a 10A circuit breaker just for added protection.

Sent from my SM-G900I using AULRO mobile app

[Blknight.aus]

for charging you'll be fine.

for maintenance.. maybe but I wouldn't unless you've got a parasitic drain constantly on the battery

Jaycar and altronics have a small black box regulator which would be ideal the same sort of one is available from ebay and the like for a lower cost.

[drivesafe]

Hi Magnet, as Dave posted, "unless you have parasitic drain" and you do.

The isolator will be using a constant small amperage and while all the new versions have the TIME-OUT feature, this only operates if the battery voltage drops below 12.7v and stays below that level for seventy two hours.

With your setup, using the solar to charge and maintain the batteries, every "SUNNY" day, the solar will raise the voltage over 13.2v, the TIME-OUT reset voltage level, and so your isolator will be on all the time.

This is not a problem and will allow you to use the 20w solar panel with out a regulator.

BUT, after a few days of sunny weather, in the afternoon, while the solar is getting good sun coverage, measure the voltage and make sure it is not above 14.5v.

[Tombie]

I have 2 x 15w panels keeping the boat batteries charged...

Seems to be working fine. Haven't observed any ill effects in 18 months. (Sadly the boat hasn't gone out on the water due to other factors).

Motors are started and run regularly and battery condition always appears good.

[Ooops]

Thank you Drivesafe that was just what I was looking for.

For completeness the system fitted is your D3-BS = SC80-LR + ABG-25

Just so that I'm clear, when you say
measure the voltage and make sure it is not above 14.5v.

Am I to take this measurement at the battery with the panel connected?

In real world use is there a likelihood that this combination will exceed 14.5v or will the parasitic drain keep it at this level?

If it stays at 14.5v or less can I keep it connected long term for on going battery maintenance?

I bought the wattsup meter that you mentioned some time back. I plan to connect that between the panel and the battery to get a continuously updated read out.

Sorry if I'm missing the point but I'm new to solar and the wattsup meter

[Blknight.aus]

You should take the measurement with the panel in full sun with all of the batteries fully charged and all of the vehicles loads off. (parked for 3 days undisturbed or however long it takes your particular vehicle to go into hibernation mode)

from memory the total parasitic draw from a D3 in hibernation mode is in the order of a 200mA and the traxide is 80 or so.

your 20W panel will push an average of 20ah into the batteries if you set it up correctly which is something like twice what the parasitic load is.

Given long enough (or if you go park in the tropics) that will eventually cook your batteries if left unregulated.

Personally (and this is one of those things drive save and I have differing opinions on) I think 14.5 is too high for a floating voltage and should be considered to be the peak disconnect voltage.

I would also check the current flow while its hooked up.

The numbers I would be looking for would be around 13v with good current flowing from the panel (so on a 20w panel up to 1.7A) with the amps reducing to 0 by about 14.2V

[Ooops]

Dave many thanks for the input.
In order to understand you properly I have a few more questions, I'm not second guessing you I'm trying to make sure that I've understood you correctly .....


You should take the measurement with ..... or however long it takes your particular vehicle to go into hibernation mode)
Great thanks. Hibernation occurs as soon as the hand brake light goes out which is about 3 minutes



..... or if you go park in the tropics
My Australian based reading tells me people base their calculations on 5 to 6hrs quality sun per day.
I'm currently in the Middle East so the panel sees full sun every day. Should I adjust the 5 - 6hrs sun upwards to perhaps 8 hrs a day for the purpose of calculations?



total parasitic 200mA and 80 ......... 20W panel will average of 20ah ..... twice the parasitic load.

So you've calculated
total parasitic draw per day as 0.28aH x 24hrs = 6.7aH
panel output per day as 1.70aH x 6hrs sun = 10.2h or nearly double
Have I understood correctly? Where did 20ah come from?

As a battle field measure to get the 10w performance can I simply cover up half the panel?
I realise a reg is the answer but just so that I know.


I would also check the current flow while its hooked up.
I'm having trouble interpreting the dta that the wattsup meter is giving me. I'm in danger of having to read the instructions :D

On a completely different tack what would be the duty cycle for a Waeco CF50 run at decent beer temps in an ambient ranging between 40 and 50?C

[drivesafe]

Hi Magnet, and sorry this is so long but here is a bit more info on using unregulated solar panels to charge and maintain batteries with safety and how it works.

There is a lot more to it but I will try to keep this in an understandable form.

All batteries have an internal resistance and this resistance is the reason for the amount of current a battery draws, while charging.

With all forms of resistance, as you increase the voltage difference across the resistance, there is a corresponding increase in the amount of current travelling through that resistance.

This current travelling through a battery is commonly termed as the current load, and from this point on, to keep this as basic as possible, I will not use resistance and only refer to the current or current load.

To charge a battery you need both a voltage higher than the battery's State of Charge voltage ( SoC ) and some amount of current.

If you are charging from an alternator and you have a very low auxiliary battery ( in most D4s, this will be an Optima 55Ah AGM ), then there is going to be quite a high current being drawn by the auxiliary battery, and this current draw can initially be as much as 100+ amps.

In the above case, your auxiliary battery can only draw such a high current because the D4 alternator is capable of producing those sorts of currents.

With your 20w solar panel setup, the VERY maximum current available current, and this will only be for a few hours a day, is around 1.25A.

Over an 8 hour period of good sunlight, you would be very lucky to average as much as 1A. With no load applied to a "12v" solar panel ( called open circuit ), the panel can generate up to 24v

The reason for the difference between the rated wattage and the actual wattage you end up with is because of two related factors.

The first is that to try to get as high an output from a solar panel all day long, you need to have the solar panel track the sun. This means, the solar panel must continually be repositions so that it is facing directly at the sun, as the sun moves across the sky, from horizon to horizon.

Your setup will, like the vast majority of solar panel setups, will have the panel facing directly at the sun for no more than a few hours.

And as this wasn't enough to reduce the average amount of power coming from the panel, at the point where the panel is facing directly at the sun, the sun's energy will heat the panel and as a solar panel's temperature rises, it's total wattage output reduces.

So at the very time you think you are getting the maximum POTENTIAL ( 20w ) output from your solar panel, it will actually be down by as much as 30% ( down to around 14w ) .

OK so that covers the very basics of battery charging and solar energy production. Now to put the two together.

As above, a 20w solar panel has a maximum current output of just 1.25A and this will be for a small portion of a sunny day.

So at best, you have a charge current of 1.25A, and if you battery is low, it will be trying to draw all the current it can get.

Now if you apply a high current draw to a solar panel, the panel will produce all the current ( watts ) it can but the much higher current draw of the battery will pull the solar panel voltage down to pretty close to the battery's internal voltage.

So if the battery voltage is at say 11.0v, the solar panel voltage will be around 11.2v at the battery's terminals.

With this sort of very low current charge, it will take quite a few days before the battery gets anywhere near a fully charged state. But once fully charged, the battery will now draw very little current, so the solar panel voltage will rise at a greater rate than when it was being used to charge the low battery.

With a fully charged battery ( around 12.7v ), even a small current applied will raise the battery's internal voltage considerably.

So at the peak of the day, when your solar panel is putting out it's maximum current ( wattage ) the voltage at the battery will now rise substantially.

But as the solar voltage at the battery rises above the battery's internal voltage, the higher voltage difference will cause the battery starts to try to draw more current, and this higher current draw only has 1.25A available ( the maximum output the 20w solar panel can ever produce ) so the solar panel voltage can only rise until it reaches the solar panel's maximum current ( wattage ) output.

The batteries literally become their own voltage regulator.

Magnet, with your setup, the maximum likely voltage, at the high point of the day, is not likely be much over 14.0v

NOTE, if you use a larger unregulated solar panel, while the batteries will still act as their own voltage regulator, the high current ( wattage ) available will mean the voltage at the batteries will rise.

For instance, I use an 80w unregulated solar panel to recover badly sulphated batteries and a 100Ah battery will rise to 17.5v using an unregulated 80w solar panel. PS, do not carry out this type of charging on a good battery.

Your batteries can tolerate 14.7v for a number of hours each day, with little effect on the batteries. For example, your D4 alternator can run at 14.7v for long periods of time, depending on the state of charge of your cranking battery, and this high voltage has no effect on other batteries connected to the alternator, even if they are already fully charged.

Solar charging in some ways is very like charging from an alternator. When charging from an alternator, you have to be driving and few people drive long enough for even 14.7v to effect battery longevity.

With solar, the similarity is that it only charges the batteries while the sun is shining and even then, it only charges at the solar panel's maximum possible current ( wattage ) for a short period of time.

As Dave posted, test your battery/solar voltage at the high point of the day, and you will then know for sure that you will never over charge your batteries, no matter how many weeks/months you leave them in this type of setup.

[Ooops]

... sorry this is so long but here is a bit more info on using unregulated solar panels to charge and maintain batteries with safety and how it works.
Drivesafe that's a brilliant explanation, many thanks
It even helps me understand what the wattsup meter's telling me


All batteries have an internal resistance and this resistance is the reason for the amount of current a battery draws, while charging.

I get that lower battery SoC causes higher charging current draw i.e. the battery's starving and gorges itself and that the process slows up as the battery fills. Its the concept of ?internal resistance? that I'm not seeing. I can't quite grasp the principle that's in play here, do you have an analogy for this?

We've been talking about the D3 dual battery system with AGMs which I assume the panel treats as one big battery with the isolator open and one smaller battery with the isolator closed. Imagine a situation where the panel wasn't connected and the D3 battery voltage had dropped sufficiently to cause the SC80 to separate the aux from the crank battery. If I were to connect the panel through my rear Anderson would the isolator reopen when the aux was sufficiently charged?

In general non D3 use, does the size & type of the battery matter? Can I use this system to maintain individual lead acid 12v batteries on the bench or should they be wired to form a bank? Keeping them wired together would certainly be more convenient.

Does 14.7v remain the max acceptable voltage at the high point of the day or does it drop for non AGMs?

[Blknight.aus]

Dave many thanks for the input.
In order to understand you properly I have a few more questions, I'm not second guessing you I'm trying to make sure that I've understood you correctly .....


Great thanks. Hibernation occurs as soon as the hand brake light goes out which is about 3 minutes


My Australian based reading tells me people base their calculations on 5 to 6hrs quality sun per day.
I'm currently in the Middle East so the panel sees full sun every day. Should I adjust the 5 - 6hrs sun upwards to perhaps 8 hrs a day for the purpose of calculations?



So you've calculated
total parasitic draw per day as 0.28aH x 24hrs = 6.7aH
panel output per day as 1.70aH x 6hrs sun = 10.2h or nearly double
Have I understood correctly? Where did 20ah come from?

As a battle field measure to get the 10w performance can I simply cover up half the panel?
I realise a reg is the answer but just so that I know.


I'm having trouble interpreting the dta that the wattsup meter is giving me. I'm in danger of having to read the instructions :D

On a completely different tack what would be the duty cycle for a Waeco CF50 run at decent beer temps in an ambient ranging between 40 and 50?C



The 1.7A I came up with for yours was from one quick google search for 20w panel info and is the dead short value for some panel somewhere.

Its not what you will get out of the panel for charging purposes and calculating how much you can put into the battery for working out how long the fridge will work for. But youre not using the panel in that way. your using it for a maintenance charger so the worst possible case is the maximum current at the maximum voltage the panel can produce.

20aH is a typo I didnt pick up. it should have been 10Ah.

as for the waeco question.. Id expect it to be in the 70% duty range depending on airflow what bag its in, if its in direct sunlight the humidity......

IT could go as high as 100%

and thats assuming you like your beer at 4 deg C.

for the towel on the panel trick...

that depends on how the panel is set up some panels will provide partial power in partial shade some wont.

usually the panel will have a bunch of smaller cells wired up in a series/parallel configuration, if you block off a complete row of cells that are in series with each other the panel should put out a lower total amps but the same voltage.

if you block off a set of cells that are in parallel the voltage will drop but the amps should stay the same.

[Ooops]

Dave, many thanks for the explanations and the 'towel on the panel? trick


thats assuming you like your beer at 4 deg C.
absoballylutely, anything else just isn't civilised:D

The fridge is kept in a Waeco travel bag. The bag has some insulation but not enough to be of real use. The fridge is never in direct sunlight but I do need to find a way to upgrade airflow around it

[Ooops]

I've been experimenting with a single 55Ah Optima
A day or two back, at the start of the experiment, the voltage was 11 something v. Today the wattsup meter was showing just over 15v on the load side.
When I disconnected the panel I got 12.3v on the multimeter

Dave & Drivesafe, based on your instructions the battery's seeing too much voltage but when disconnected from the panel its below full charge at 70%

Should I keep charging until the disconnected reading is 12.7v?
If so what sort of reading should I expect to see on the load side of the wattsup while its all connected?

[drivesafe]

Hi Magnet and I use similar devices for doing basic tests.

But no mater what type of meter you use, because of the effects of voltage drop, the meter needs to be as close as practical to the battery, and you need to use decent cabling between the solar panel and the battery.

Where is you meter connected and what size cable are you using?

[Ooops]

the meter needs to be as close as practical to the battery ..... Where is you meter connected
Its 12" of wiring away from the battery


what size cable are you using?
I'm using a 10m piece from a 220v ext cable, the thinnest wiring is 2mm across excluding the insulation

[drivesafe]

If you have a separate multi meter, try measuring the voltage at either end of the wire, while the solar panel is connected and the sun is at it's brightest.

Also, your Wattsup shows watts and current going passing though it. Note both of those at the maximum sunlight.

As for your batteries, 20w is way to high for charging a single battery ( without using a solar reg ) . But an unregulated 20w panel is fine when charging your two batteries at the same time, plus you will be powering your isolator as well.

[Ooops]

try measuring the voltage at either end of the wire, while the solar panel is connected and the sun is at it's brightest.
20v at both ends with no load
I haven't tried it at both ends while under load


Wattsup shows watts and current going passing though it. Note both of those at the maximum sunlight.
I'll report back


20w is way to high for charging a single battery ( without using a solar reg )
Noted, thanks. I have six old batteries in various states of decline. Am I right in thinking that I can bank these up and use the 20w?

Last question, there's some great deals to be had on cheap & basic controllers out your way but getting suppliers to post out of country is proving to be an issue. Do you know off hand of any firms that post overseas?

Thanks again

[Blknight.aus]

for unmonitered charging 20w is too high, for monitored charging go as big a panel as you like BUT you must manually monitor the voltages and current flow. (another thing drive safe and I have a differing opinion on is panel regualtion for some charging applications)

jump on the jaycar site and get the model off their cheapy regulator then go buy one from ebay if they wont still ship over seas.


No you cant just stick the 6 batteries on as a dummy load as they will drain the voltage over night.

the easiest form of regulation is a light bulb as you current limiter and a blocking diode.

BUT..

that wastes a lot of your available power.

[Ooops]

Wattsup shows watts and current going passing though it. Note both of those at the maximum sunlight.
I was screwing around with the panel to see how it was constructed and whether or not I could remount the cells and ....... I broke it :censored: Well I cut one of the wire traces. It took a while before I soldered it up so no meaningful readings today


for unmonitered charging 20w is too high .... you must manually monitor the voltages and current flow.
Thanks for the feed back Dave
Is 12.7v to 13v the correct voltage to disconnect at?
The light bulb idea is really clever, I'll be getting a reg but you've got to love that idea

Dave slightly off topic
I've recently read a post from you suggesting a diode and one cheap reg per panel.
I've read a number of posts recommending that for mobile panels the reg be placed as close to the battery as possible
How does that work with one reg per panel?

[drivesafe]

Is 12.7v to 13v the correct voltage to disconnect at?

Hi Magnet, 13.0v is way to low and you will not charge a battery or batteries.

You need a CONSTANT charge voltage of at least 13.7v or the batteries will never reach a fully charged state.

The MINIMUM voltage required to be able to fully charge an Optima is 13.65v

With solar charging, the voltage is not CONSTANT, so if you don't allow the charge voltage to get to at least 14.0+v ( 14.7v is the maximum safe voltage for any lead acid battery ) for part of the day's charge cycle, again, the batteries will never reach a fully charged state.

Furthermore, with your setup, where you will be charging two batteries at once and replacing the energy your isolator draws overnight, the current load being applied to the 20w solar panel means it is highly unlikely you will ever get much over the 14.0v.

[Blknight.aus]

I was screwing around with the panel to see how it was constructed and whether or not I could remount the cells and ....... I broke it :censored: Well I cut one of the wire traces. It took a while before I soldered it up so no meaningful readings today


Thanks for the feed back Dave
Is 12.7v to 13v the correct voltage to disconnect at?
The light bulb idea is really clever, I'll be getting a reg but you've got to love that idea

Dave slightly off topic
I've recently read a post from you suggesting a diode and one cheap reg per panel.
I've read a number of posts recommending that for mobile panels the reg be placed as close to the battery as possible
How does that work with one reg per panel?

the one diode and cheap reg is for different panel set ups where you have the panels setup for different things, (one on the car, one on the camper and one portable for example) using different size panels.

If you gang panels into a single array then usually you would put in the diode at each panel and the reg near the battery, Most regs now include a blocking diode function so if you go one reg per panel you remove the need for the diode.

Regulator as near to the battery is the right way to go as it helps reduce cable losses

13.0V will charge a battery but only from a lower state. to charge a battery to full capacity you need a higher voltage 13.8V is what I consider to be the floating voltage and 14.4 a normal maximum charging voltage For what you are doing which is maintaining the battery on an essentially unregulated panel I would only want to see 13.8V as the maximum voltage. Regulated with a properly staged regulator 14.4 for bulk or absorption charges, 14.7 for the peak charge voltage with a 13.8v -14.2 for the float depending on the battery and any parasitic loads.

Other than the few minor differences in opinion about max voltages, rates and panel regulation setups Drivesafe is giving you good oil from the same page of the book as I am. His setup and voltages give you a much higher state of charge than mine (remember I'm only aiming to stave off sulphation and enough to start) but carry more potential risk if something goes wrong. My numbers leave you with a lower state of charge in the batteries (but not a flat battery) and in the main part thats due to what we are personally willing to accept due to what we expect from the system and have experienced in our employment in this field.

Conversly Drive safes systems cut out earlier and shut down with more left in the battery which gives you a better option if you get desperate. Stuff I do tends to leave you a lot closer to battery damage and having dead flat batteries IF you use all of whats available

All of drivesafes info below I agree with


Hi Magnet, 13.0v is way to low and you will not charge a battery or batteries.

You need a CONSTANT charge voltage of at least 13.7v or the batteries will never reach a fully charged state.

The MINIMUM voltage required to be able to fully charge an Optima is 13.65v

With solar charging, the voltage is not CONSTANT, so if you don't allow the charge voltage to get to at least 14.0+v ( 14.7v is the maximum safe voltage for any lead acid battery ) for part of the day's charge cycle, again, the batteries will never reach a fully charged state.

Furthermore, with your setup, where you will be charging two batteries at once and replacing the energy your isolator draws overnight, the current load being applied to the 20w solar panel means it is highly unlikely you will ever get much over the 14.0v.

This is the key difference between drivesafes setup and mine. He is advising from what happens in 99.5+5 of situations.

I'm safe guarding against the .5% as well BUT if you follow what I'm advising your battery might only ever get to say 80% charge if you go with drivesafe it will get to nearer 100% charge BUT IF something oddball happens you carry a slightly higher risk of something having its life expectancy shortened OR burning out.

[Ooops]

Gentlemen thank you both for your patience and the continuing education. I find this stuff to be quite fascinating and the more I look the more questions I have, consequently this post is a bit long winded


Hi Magnet, 13.0v is way to low and you will not charge a battery or batteries ..............


Other than the few minor differences in opinion about max voltages, rates and panel regulation setups Drivesafe is giving you good oil from the same page of the book as I am ..............

His setup and voltages give you a much higher state of charge than mine .... but carry more potential risk ...I'm only aiming to stave off sulphation and enough to start

...My numbers leave you with a lower state of charge in the batteries (but not a flat battery) ...Stuff I do tends to leave you a lot closer to battery damage and having dead flat batteries IF you use all of whats available

Drive safes systems cut out earlier and shut down with more left in the battery which gives you a better option if you get desperate.

This is the key difference between drivesafes setup and mine. He is advising from what happens in 99.5+5 of situations.

I'm safe guarding against the .5% as well BUT if you follow what I'm advising your battery might only ever get to say 80% charge if you go with drivesafe it will get to nearer 100% charge BUT IF something oddball happens you carry a slightly higher risk of something having its life expectancy shortened OR burning out.


Gentlemen forgive me, I think I muddied the waters by asking two different sets of questions and changing back and forth between the two. And I'm about to add a third set.

Originally my questions were specifically related to the unregulated charging of my Traxide equipped D3 and then I swapped to the unregulated charging of stand alone batteries as individuals and when banked

You've given me terrific information on both setups and despite appearances I haven't confused the two.

So far I've only experimented with the monitored charging of a couple of individual, stand alone batteries which is why I was asking about the appropriate voltage, (Vm I guess?), at which to disconnect. However this morning I've connected up to the D3 through the rear Anderson and I'll report my findings as I go.

To muddy things up even more I'm going to ask a few questions about customising the panels


.....Furthermore, with your setup, where you will be charging two batteries at once and replacing the energy your isolator draws overnight, the current load being applied to the 20w solar panel means it is highly unlikely you will ever get much over the 14.0v.
I've seen Traxide based installations that used three batteries. Would the the traxide and solar combination apply the same charge & maintenance parameters to a three battery, (or more) installation?

Specifically I'm wondering if I could further leverage the benefits of the solar traxide combination by connecting a stand alone battery, by way of a temporary lead, to my D3's auxiliary battery. Would the temporarily attached stand alone battery, or a camp battery box etc, receive the same level of charge & maintenance?


..... 13.0V will charge a battery but only from a lower state .... For what you are doing which is maintaining the battery on an essentially unregulated panel I would only want to see 13.8V as the maximum voltage.
Just what I was looking for, thanks. In that specific application I'll experiment with covering parts of the panel to get that sort of performance


..... If you gang panels into a single array then usually you would put in the diode at each panel
Can I take it that the item in the photo is a diode? I'm learning about how these things work but it surprised me to see it bridging both the + & - panel connections.

With regard to ganging panels, I'm running a CF50, a few lights and a computer and research suggests that I need 160w of panel. That figure varies from author to author anywhere between 80w and 160w. I need to figure out what's correct for my needs.

I thought I'd start out with 80w, set it up at home and run it day and night for a week and see how that fairs. I can use the Wattsup meters to get real world information. If required I can add additional panels until I get to total self sufficiency.

The 20w panel I have is of a manageable size for handling, transport and storage so I thought I'd hinge them in pairs and have as many pairs as required.

The downside is that the panel and frame combined are 30mm deep. Whilst not outrageous it's bulkier than it needs to be. The current depth is just enough to be above the plastic junction box that houses the diode.

To make it easier to pack I'd like to cut the frame down to a depth of 10mm of which 5mm would be panel. I want to cut off the plastic box and either embed sockets into the frame or have a trailing lead coming directly off the panel.

All of the above leads to the questions,



If paired together does each individual panel still require a diode or will one for each pair of panels suffice?


If there's insufficient space within the frame, where & how to mount the diode?


Can I incorporate the diode into any of the leads, perhaps the panel to panel lead or the leads that join the pairs of panels together or in the main extension that runs to the reg?

Gentlemen, all of the points made in your responses have been well received and taken together have given me an excellent grounding:Rolling: and much improved understanding of the subject. I've still got a fair way to go so I'm sure there'll be further questions at some point but in the mean time many thanks for the education:TakeABow:

[Blknight.aus]

lots of questions gets lots of answers, remember the only dumb question is the one you thought of but never asked.

Proof of that can be found on aulro generally by the thanks a post gets, as a ready reckoner if you see an informative post in a tech thread and it has a lot of thanks on it then roughly speaking it means the people who put thanks on it gained information from the post thats in reply to the original question.

the first question Im going to answer is the one that relates to what size panel you need. Thats one of those that depends answers.

Theres 2 schools of thought on solar on vehicles.

1. The panels need to provide enough to allow you to remain in place with out an external power input (running the engine/genny/powered camp site)
2. The panels are only a back up supply that provide limited charging ability to allow you to extend your stay in an unpowered location for longer than just your battery system normally allows. (Im in this bracket my setup allows for a weeknds camping but my aux battery is flat by the morning of day 3 and Im depending on the panel to get through day 3.)

If you're in the first group your going to wind up with big panels and smaller batteries (as the batteries only need to deal with over night) and the second usually have smaller panel setups but more battery capacity.

with that question answered you can then work out how much of each you need. but to do that you need to know how much your going to draw so you can work out how much you have to replace. Very vaguely speaking.. Those from group 2 generally put on just enough panel to keep up with the load during the day and tax their batteries during the night (and 80w is about right for a single fridge a radio and some other intermittent misc loads) and the first group generally just take that number and double it (theres your 160w answer) they also tend to have better panel setups that are removable tiltable with top of the line regulators.

Next... Charging and unregulated panels..

Charging batteries is an art form ,just as some people will allude spark wrangling and spanner twirling can be art forms... sure almost anyone can paint by numbers and do it but that only gets you so far. So heres my intro 101 paint by numbers level on charging batteries from unregulated panels

For charging..

Batteries have lots of numbers around them and cover lots of details, the 2 that count most for basic charging are 1. the max charge rate (amps) and 2. the max charge voltage.

Now assuming you only want to keep your batteries between 60 and 80% charge (more than enough to start your car) with the 20W panel what you need to work out is what is 10% of the maximum charge rate of your batteries.. if the panel is capable of putting out more than that 10% then Dont do unregulated charging.

If the panel can only ever put out less than 10% of the max charge rate then you're good to run unregulated.

heres the kicker for you, you have a traxide and more than one battery. So hook the 20 w maintenance panel up to the main battery. When the panel charges up the main battery (and lets just for this example say that the panel is too big for the main battery by itself) the traxide links the aux batteries in (and lets say that by themselves they are too small for the panel by themselves) when you add all the batteries together if 10% of the total charging amps (they add together because the traxide parallels batteries) is more than best amps the panel can put out you are good to go. Plug in the batteries to the traxide put the panel on the main battery and forget about it it will self regulate because ... (insert more complicated white man magic explanation here or re-read one of drivesafes earlier posts for the general gist)

No, when you hook all of the batteries up via a traxide unit and plug a small panel on they dont all get the same charging characteristics, But we're faffing about in a world of technicalities you dont need to get caught up in for what you need to know. the basic (10% of total charge amps of all batteries) > (max panel output amps) covers what you need to know. In a perfect world On average all off the batteries will receive their portion of the panels out put based on the following formula (Panel output)/(# of batteries)

the thing in your picture is infact a diode, and it looks like its wired up as a shunting diode. ( only looked at the small pic and your description)

Diodes are one way gates for sparky bits and on solar configurations they can be used as shunts or as blocks and depending on what you do you may need both.

as a shunt its there to bypass the panel in an array so if the panels not putting out enough grunt the rest of the power from the array can pass through.

As a block its there to stop the panel from drawing power when its not working.


Where you mount it is simply a case of working out what you need it to do (if you need it) and then sticking it into the wiring in such a way that if you were to look at it from a wiring diagrams perspective its wired in the same way. BUT if you're using long removable cables and put the diode in the cable you need to both polarize and orient the cable so the diode cant go in the wrong way.

Hope that helps.

[Ooops]

Wow Dave, awesome information. I think for the first time in a long time I'm out of questions. Well that's until the morning when I've slept on it :D


Theres 2 schools of thought on solar on vehicles.
In relation to this discussion I'm in the first group.

Summer temps are 40-55? ambient with high 30?C at night not uncommon so every thing is working very hard. The majority of my trips are one or two nights, some times a bit longer. However nearly every day sees me doing several hours of driving. Along with a couple of tricks,

..... who ever the person was who came up with the wet t-towel as a zone divider between frozen and chilled deserves a ?kin knighthood and a free beer from every fridge running travel that he or she meets for the rest of their lives! :TakeABow::TakeABow:.......

I turn the temp down while driving and turn it up overnight. The awesome traxide system, does exactly what it says on the tin & supports this style of travelling brilliantly. If I do my bit with managing the fridge correctly every thing is fine. On rare occasions I mess it up and the fridge is off when I wake up but the contents are always as cool as they need be i.e. frozen is still frozen and beer is still chilled. Of course the car starts perfectly so things are quickly back to how they should be. There are settings on the ABG25 and the fridge that can be changed and I'm sure that if I played with these I'd never have any issues but by the time I stop again and have the time I've forgotten all about them so they've never been interfered with.

That said, I'm hoping to start getting away for longer trips where I hit a spot and stay. There'll little or no daily driving, I may need to run a second fridge or freezer and I hope to be out there for a week at time, some times longer. That's what puts me in the first group



Charging and unregulated panels..
.... assuming you only want to keep your batteries between 60 and 80% charge
.... 10% of the maximum charge rate of your batteries.
.... if the panel is capable of putting out more than that 10% then Dont do unregulated charging

Another great rule of thumb, thank you


On average all off the batteries will receive their portion of the panels out put based on the following formula (Panel output)/(# of batteries)
Brilliant.


Plug in the batteries to the traxide put the panel on the main battery and forget about it

Thinking in the abstract and still with unregulated could I make up and use an Anderson Y adapter lead that allowed a simultaneous connection between the panel, the D3 and anything else that I wanted on charge at the same time, using the SC80 to keep voltage in check?

For regulated battery maintenance for the D3 I'm looking at this from the point of view that the vehicle is parked in a reasonable state of charge so the isolator will be open and both batteries connected so at the moment I've plugged into the rear Anderson.

I appreciate that if before the solar connection is made the battery voltage had dropped (12.7 and below?) the isolator would have done its job & a connection through the rear Anderson wouldn't charge the crank battery. In such cases I know that when the car is started and crank battery voltage is sufficient the isolator will rejoin both batteries. What I'm unsure about is whether or not the isolator automatically rejoins the both batteries when it senses the aux battery has reached a decent level of charge. If that's the case then I can use the rear Anderson for all charging, if its not I may have to consider a comfort lead. In my situation its a bit of a mute point because when I park up the isolator's always open and the connection would be made at the rear for pure convenience.

However every now and then the car doesn't move for a week or two and occasionally I've been caught out with flat batteries. Last time I had to recharge using a USB phone charger. That's why I not only asked about the correct way of using a panel but also about the down and dirty, battle field options for when its all gone horribly wrong. The light bulb trick is genius, I haven't got any but its still genius.


Diodes ..... can be used as shunts or as blocks and depending on what you do you may need both.
More great info. I'll try and leave the configuration as it is and rely on the regulator for polarity protection

Absolutely brilliant info, many thanks for taking the time to break it al down for me

[Blknight.aus]

Now I'm getting onto what you actually want to be able to do.

I believe the newer version of the traxides sense from both sides so so long as A battery gets above its nominal voltage the system will hook them all up. If you have the newest one you should be good to go.

Battlefield charging as you're calling it (emergency charging) is not about looking after anything, its whatever it takes to get enough into the battery to get you a start. in which case grab your 160w panel hook it up to the battery and watch the multimeter, as soon as it shows 14V crank the engine and disconnect the panels.

Due to the short time you do it the panels never punch enough into the battery to get to the damaging voltage phase.


For maintenance charging off of an unregulated panel while the no more than 10% max rule will stop you from hurting things if you go to small then the panel wont keep up with your parasitic load or the self discharge rate of the batteries.

What I think you want is...

about 100AH of actual battery capacity over and above the discos starting battery

about 200w worth of mounted regulated charging panels for when you're out camping and staying fixed for a week at a time (this just manages 2 fridges in good conditions)

a 20w maintenance panel for when you have to park it up for a week without the fridges and stuff on.

[Ooops]

the newer version of the traxides sense from both sides

I have the older one, perhaps I'll get an upgrade from Santa

Yesterday morning I connected into the D3s rear Anderson, I believe I measured 11.9v at that time. The car had been parked for five days having only made a couple of short trips to the village and back before that.

This morning I discovered that I had previously been talking tosh :censored:when I checked yesterday's performance the isolator had done its job and the rear connection was only charging the aux.

I fired up the D3 for a minute or so, the isolator opened and I continued charging from the rear Anderson. It proves your point about a crank battery connection being the bullet proof one. I'll need to pay attention to voltage before making the rear connection in future.

Its probably just me but I find using the rear quicker and cleaner than going under the bonnet.


emergency charging .... watch the multimeter, as soon as it shows 14V crank the engine and disconnect the panels.
Brilliant


What I think you want is...
... 100AH over and above the discos starting battery
... 200w regulated .... when you're ...staying fixed for a week
.... 20w maintenance panel
Again brilliant, than you. This gives me a great .......... starting point :Rolling:

So your battle field calc for ?group 1 stay in one place people? is a 2w:1aH ratio

For now I'm only running the one fridge so I'll start with the 80w discussed earlier and see how that goes.

If a second fridge/freezer is required I'll upgrade to the 200w

Perhaps not the ideal choice, I have a spare Optima red top looking to make its self useful, together with the yellow top already fitted that puts me within spitting distance of your 100aH

You're the man Dave, many thanks
:TakeABow::TakeABow::TakeABow:

Now you'll have to excuse me, I'm off to PM drivesafe about a new isolator and a handful of Andersons :D

Olly

[Blknight.aus]

Brilliant


So your battle field calc for ?group 1 stay in one place people? is a 2w:1aH ratio

Not quite, thats just how the rough numbers worked out in this case. When people want me to spec up a stay in place system theres a lot more questions and real life testing done to confirm numbers because no one runs "just a fridge" everyone has a lot of other little things that add up over time.

For the numbers I threw down for you I basically took the numbers for my system, doubled the fridge draw left the misc values totaled them then doubled it for the solar watts needed and rounded up to the next convenient panel size. I then doubled the aux battery capacity to deal with the extra fridge over night. What should get you though on that is the doubling of the misc values + the round up factor combined with the benefits of the bigger batteries and the traxide. IT should get you to about 7 maybe 8 days but you'll still wind up against batteries in a lower state of charge than when you started.

For the stay and live on solar deal you need (roughly) 3 times the amount of draw you expect the system to deal with as your charge ability and thats only properly viable while everything is 100% in reality i'd spec up nearer to 4 times.



For now I'm only running the one fridge so I'll start with the 80w discussed earlier and see how that goes.

With that you're running essentially the same system I am, with just a single engle and no accessory load that will just about keep you infront indefinately but add some sub optimal charging factors, some lights, a radio, charge a phone and the laptop and you're behind. I think that this will get you about 3 days in location but the battery will be drained on day 3 and you'll need to move on to charge the batter(ies). The traxide will give you a little more by the magic it does But I dont have one fitted because of a very special way I need to be able to abuse my setup that the traxide system was never intended to deal with (jump starting 24V out of a 12V system and welding off the batteries)



If a second fridge/freezer is required I'll upgrade to the 200w

Perhaps not the ideal choice, I have a spare Optima red top looking to make its self useful, together with the yellow top already fitted that puts me within spitting distance of your 100aH


The configuration and build sequence you really want here is a little different..

Fit the 80w panel to the vehicle, add its regulator and couple it to the main batery. Your now set to go with a single fridge for about 3 days. Your system, charge wise wont be any better than mine but you have the advantage of the traxide which in terms of real life will put you about 30% ahead of how my setup works. maybe more if you use better batteries, panels and regulators. I've put this first as it sounds like you already have all of this gear.

next get yourself the upgraded traxide you wont see an obvious and immediate change to how your system works but trust me for the next bit you will.

then get yourself a second panel set or array when you start hooking up the next fridge/freezer. This set you hook up to your aux battery or the anderson plug with a dedicated regulator.

This gives you the most cost effective and flexible setup. youve got a panel set on the vehicle that looks after the main battery all the time and via the magic of the traxide the aux battery as well when the main battery is mostly charged. (which means you're not letting solar power goto nowhere when the battery is charged)

When you expand you have a second complete solar system that is not anchored to the vehicle so you can use it elsewhere or position it else where and with the newer traxide looking after things if you have to park the vehicle in the shade you can use the solar or any other charger to get all the batteries back up. IF you want you can even remove the second (third) battery and mount it to the second solar system to look after one of the fridges if you need the space in the vehicle.

if your parking it all up you can put the small maintenance panel onto the system anywhere and it will look after everything. (with the early traxide you must connect to the main battery with the later any will work)

[Graeme]

the thing in your picture is infact a diode
That diode will either be a standard diode providing reverse polarity protection (if indeed solar panels can be damaged by reverse polarity connection) or more likely a Zener (avalanche) diode with a reverse flow trigger voltage set to limit panel voltage, which would also provide reverse polarity protection. A Zener diode conducts in the normal direction until its trigger voltage occurs whereupon it conducts in the opposite direction. Cool solar panels that have been in shade suddenly getting full sun can generate quite high voltage spikes so a Zener diode with an appropriate trigger voltage prevents those spikes from going anywhere.

The diode does not isolate a non-performing panel - a non-performing panel simply doesn't contribute useful power. I use a portable panel pair in parallel with the fixed panel on my van to keep the battery topped-up whilst the van is in a shed, without isolating diodes for any panels.

[Aaron IIA]

The diode in the picture is connected as a bypass diode. If you have multiple panels connected in series with one in shade, that diode will allow full current to bypass that panel. Without it, if you shade one cell in a multiple panel series connected system, the current of the whole system drops. With the bypass diode, the system voltage will drop by the voltage of the panel that the diode is bypassing, but retain full current output. If you only have one panel in the system, with only one bypass diode on that panel, them that diode serves no purpose. If you directly connect a panel to a battery in reverse polarity, the bypass diode will present a short circuit.

Aaron

[DiscoMick]

Not quite, thats just how the rough numbers worked out in this case. When people want me to spec up a stay in place system theres a lot more questions and real life testing done to confirm numbers because no one runs "just a fridge" everyone has a lot of other little things that add up over time.

For the numbers I threw down for you I basically took the numbers for my system, doubled the fridge draw left the misc values totaled them then doubled it for the solar watts needed and rounded up to the next convenient panel size. I then doubled the aux battery capacity to deal with the extra fridge over night. What should get you though on that is the doubling of the misc values + the round up factor combined with the benefits of the bigger batteries and the traxide. IT should get you to about 7 maybe 8 days but you'll still wind up against batteries in a lower state of charge than when you started.

For the stay and live on solar deal you need (roughly) 3 times the amount of draw you expect the system to deal with as your charge ability and thats only properly viable while everything is 100% in reality i'd spec up nearer to 4 times.

With that you're running essentially the same system I am, with just a single engle and no accessory load that will just about keep you infront indefinately but add some sub optimal charging factors, some lights, a radio, charge a phone and the laptop and you're behind. I think that this will get you about 3 days in location but the battery will be drained on day 3 and you'll need to move on to charge the batter(ies). The traxide will give you a little more by the magic it does But I dont have one fitted because of a very special way I need to be able to abuse my setup that the traxide system was never intended to deal with (jump starting 24V out of a 12V system and welding off the batteries)


The configuration and build sequence you really want here is a little different..

Fit the 80w panel to the vehicle, add its regulator and couple it to the main batery. Your now set to go with a single fridge for about 3 days. Your system, charge wise wont be any better than mine but you have the advantage of the traxide which in terms of real life will put you about 30% ahead of how my setup works. maybe more if you use better batteries, panels and regulators. I've put this first as it sounds like you already have all of this gear.

next get yourself the upgraded traxide you wont see an obvious and immediate change to how your system works but trust me for the next bit you will.

then get yourself a second panel set or array when you start hooking up the next fridge/freezer. This set you hook up to your aux battery or the anderson plug with a dedicated regulator.

This gives you the most cost effective and flexible setup. youve got a panel set on the vehicle that looks after the main battery all the time and via the magic of the traxide the aux battery as well when the main battery is mostly charged. (which means you're not letting solar power goto nowhere when the battery is charged)

When you expand you have a second complete solar system that is not anchored to the vehicle so you can use it elsewhere or position it else where and with the newer traxide looking after things if you have to park the vehicle in the shade you can use the solar or any other charger to get all the batteries back up. IF you want you can even remove the second (third) battery and mount it to the second solar system to look after one of the fridges if you need the space in the vehicle.

if your parking it all up you can put the small maintenance panel onto the system anywhere and it will look after everything. (with the early traxide you must connect to the main battery with the later any will work)

Our system is similar.

Sent from my SM-G900I using AULRO mobile app

[Graeme]

multiple panels connected in series with one in shade...stuck in a parallel world...

[Aaron IIA]

Connect them in series, up to the maximum input voltage of your regulator. You will get higher charge current in overcast conditions. If you run two 19V panels in parallel (common camping / folding system) and a cloud comes, it may drop to 10V. No charge will happen. If you run two 19V panels in series you get 38V in sun. It may drop to 20V under cloud. This will still charge a 12V system. To get the benefits of this system, you need a proper MPPT regulator. The E-Bay $30 MPPT regulators are not real MPPT.

Aaron

[drivesafe]

All solar panels should have a blocking diodes on the output of the leads coming from the panel's connection point.

This is not to protect the solar panel, it is there to stop the battery from discharging back through the panel at night.

In Magnet's case, the diode is necessary if he is not intending to fit a solar reg.

With a single solar panel connected to a solar regulator, then a diode may not be necessary, but with parallel panels feeding one regulator, then as described earlier by Graeme, a blocking diode is needed on each panel.

[Graeme]

Any loss through the lack of a blocking diode on the non-performing panel on my van's roof whilst in the shed is inconsequential as the regulator gets to its 13.8 float voltage within a day after a few weeks without the portable panels connected. I only feed the portable panels into the van's regulator because the regulator on the portable panel conflicts with the van's good controller and pushes voltage over 15V.

[Blknight.aus]

The diode in the picture is connected as a bypass diode. If you have multiple panels connected in series with one in shade, that diode will allow full current to bypass that panel. Without it, if you shade one cell in a multiple panel series connected system, the current of the whole system drops. With the bypass diode, the system voltage will drop by the voltage of the panel that the diode is bypassing, but retain full current output. If you only have one panel in the system, with only one bypass diode on that panel, them that diode serves no purpose. If you directly connect a panel to a battery in reverse polarity, the bypass diode will present a short circuit.

Aaron


Connect them in series, up to the maximum input voltage of your regulator. You will get higher charge current in overcast conditions. If you run two 19V panels in parallel (common camping / folding system) and a cloud comes, it may drop to 10V. No charge will happen. If you run two 19V panels in series you get 38V in sun. It may drop to 20V under cloud. This will still charge a 12V system. To get the benefits of this system, you need a proper MPPT regulator. The E-Bay $30 MPPT regulators are not real MPPT.

Aaron

Arrons info is accurate and on the money. Heres how it ties into what Im proposign for you.

set up your vehicle up to and including installing the newer traxide.

When you go to get the second panel system you need to set it up as per Aarons second post with a bypass (I called it a shunt diode) and a regulator that is an MPPT capable of delivering a correct charge pattern for a 12v (nominal) system from up to whatever the maximum series voltage of all the panels you want to use adds up to +10% (a 36v array should be run from a system capable of handling 40v+)

As per Aarons first quoted post most folding systems are in parallel and they drop output voltage fast if shaded, with the voltage dropping while they are capable of pushing some amps theres not enough potential difference to let it happen. Putting the panels in series will maximise the voltage difference and provide the best use of the available amps.

(100000A at 10V will not charge a 12V battery the battery has more volts in it than the supply. 19v at .05 a will eventually charge a 12v battery)

[Aaron IIA]

If you plan to buy one panel now and more later to connect in series, make sure they have the same current rating. Voltage is not important.

Aaron

[Aaron IIA]

Any loss through the lack of a blocking diode on the non-performing panel on my van's roof whilst in the shed is inconsequential as the regulator gets to its 13.8 float voltage within a day after a few weeks without the portable panels connected.

The regulator that you are feeding the solar power through should be performing the job of the blocking diode.

Aaron

[Blknight.aus]

If you plan to buy one panel now and more later to connect in series, make sure they have the same current rating. Voltage is not important.

Aaron


The regulator that you are feeding the solar power through should be performing the job of the blocking diode.

Aaron

Just to add a little more detail, Aaron is correct but not quite for the setup I am advising.

The basics,
If you are stringing all the panels together on the same regulator in series then they have to be the same current rating. (Amax) If you are setting up in parallel then they should all be the same voltage rating (Vmax)


if you are setting up as I am advising with 2 regulators on 2 different batteries then the panels need only be the same for the configuration on each regulator.

with a single 80w panel on a regulator hooked up to you cranking battery with a single 160w hooked up on your aux battery on a seperate regulator then you dont have to worry about diodes. MPPT regulators stop back feeding and you dont have to worry about bypassing or shunting past shaded panels as you only have one panel.


If you get to 160w by having 2 80w panels on one regulator then you will need to fit a diode to each panel. If you go in series you should have a bypass or shunt diode (same thing different name) if you go in parallel then each panel should have a blocking diode.

[Graeme]

The regulator that you are feeding the solar power through should be performing the job of the blocking diode.

Not blocking to non-performing panels when the 3 panels feed a single regulator, but not a concern for my application.

[Ooops]

For the stay and live on solar deal you need ...... nearer to 4 times.
I've since seen five times recommended!:eek:


Fit the 80w panel to the vehicle .... add its regulator and couple it to the main batery.
As a permanent fixture it would be an extremely convenient fit and forget solution for day to day battery charging and maintenance. Perfect for my situation


This gives you the most cost effective and flexible setup.
This is a terrific, well thought out plan, a bloke could be forgiven for thinking that you'd done this sort of thing before:Rolling:

Seriously, I really like it but there are issues. Given I'm fairly remote to be honest for 80% of the daily driving having an 80w on the roof taking care of business would be very convenient in a fit and forget kind of way. Even more so as for my last job I started carrying the fridge permanently and haven't taken it out.

However, other than the maintenance benefits, the time I need the 80w most is when I'm on a trip and at that time I need to use the roof rack, a large panel would be in the way. My roof rack's between the rails dimensions are roughly 175 x 110cm and the local 80w panels are 123cm x 547cm. Even for daily driving when the weather's bad I need to put shovels and maxtrax up there.

Before your suggestion I was leaning toward multiple paired panels in both arrays, none of which were to be permanently mounted to the truck but now you've got me second guessing myself.

What's the work around here? Make it or them demountable?

I could live with a removable 20w, 56cm x 36cm panel up there for daily driving and plug the 80w on arrival at camp, not quite the same though, definitely not as finessed.


if your parking it all up you can put the small maintenance panel onto the system
Would this still be beneficial with a 80w already permanently fitted?


with the early traxide you must connect to the main battery
I hadn't realised that. Is there a simple explanation as to why this is the case? I'd always thought that as long as the isolator was open a rear connection to the aux also took care of the crank battery

Regulators
If using two separate and not permanently mounted arrays & regardless of their physical proximity to one another is there any reason why both arrays can't feed into a single reg of the correct capacity?

Single panel size
We've been talking about single 80w by default but originally I was hoping to get fold up / blanket type arrays but they're not available locally. Then I saw the local 20w and thought I'd customise it into a blanket configuration replacing the glass with semi flexible plastic similar to that used for laminating ID cards and the like. However after nearly trashing one I don't think it'll be possible to separate the cells from the glass. So that brings me to the idea of radically cutting down or replacing the aluminium frames and settling for pairs of panels configured in the suit case style. It might even be possible for me to trim the glass off around the margins to further reduce their size

Its not definite as I've yet to sit and compare the dimensions of the various watt size panels but I'm leaning toward using multiple pairs of 20w panels in both the stage 1 & stage 2 arrays. Its easier to pack small pairs than larger singles or larger pairs and smaller pairs will be easier to position and manoeuvre.

Any thoughts and suggestions would be most welcome

[Ooops]

If you get to 160w by having 2 80w panels on one regulator then you will need to fit a diode to each panel. If you go in series you should have a bypass or shunt diode (same thing different name) if you go in parallel then each panel should have a blocking diode.

As mentioned I'll probably get the 160w by using multiple pairs of panels, possibly 20w paired. All locally available panels, regardless of size, have those diodes fitted as depicted in the photo. Do I need to modify or add to this arrangement for an array wired in series?

[Ooops]

To get the benefits of this system, you need a proper MPPT regulator. The E-Bay $30 MPPT regulators are not real MPPT.

Aaron

Is this MPPT reg still in favour? Votronic Duo MPP MPPT Solar Regulator Charge Controller LiFePo4 Lithium Lead | eBay (http://www.ebay.com/itm/261599213144)
The possibility of exceeding 24volts hadn't occurred to me:eek:

[Aaron IIA]

I have not used that exact regulator, but it is not one of the regulators that I have specifically excluded.

Aaron.

[Blknight.aus]

I've since seen five times recommended!:eek:

Yep, it comes down to available sun time and the nature of the load, Some places Ive done the math for and come up with bigger numbers than that due to factors that derate the ability of the panel.




As a permanent fixture it would be an extremely convenient fit and forget solution for day to day battery charging and maintenance. Perfect for my situation


This is a terrific, well thought out plan, a bloke could be forgiven for thinking that you'd done this sort of thing before:Rolling:

Seriously, I really like it but there are issues. Given I'm fairly remote to be honest for 80% of the daily driving having an 80w on the roof taking care of business would be very convenient in a fit and forget kind of way. Even more so as for my last job I started carrying the fridge permanently and haven't taken it out.


If you're daily driving you dont even need the panel, with a traxide and ~60Ah worth of aux battery you should be good for 24 hours in a spot without the batteries getting flat.



However, other than the maintenance benefits, the time I need the 80w most is when I'm on a trip and at that time I need to use the roof rack, a large panel would be in the way. My roof rack's between the rails dimensions are roughly 175 x 110cm and the local 80w panels are 123cm x 547cm. Even for daily driving when the weather's bad I need to put shovels and maxtrax up there.

Before your suggestion I was leaning toward multiple paired panels in both arrays, none of which were to be permanently mounted to the truck but now you've got me second guessing myself.

What's the work around here? Make it or them demountable?


Fit the panel lenghtways in the middle of the rack at the rear in a slide out mount with QD weather proof fittings and make an extension cord to suit.

Put the mattrax and shovel to one side. MAke up a protective dome frame for the panel so if you have to load ontop of the panel you can do so. if you dont have to keep the panel clear. OR....

make a pod roof case (they're more areodynamic anyway) and incorperate the panel into the topshell.



I could live with a removable 20w, 56cm x 36cm panel up there for daily driving and plug the 80w on arrival at camp, not quite the same though, definitely not as finessed.


Would this still be beneficial with a 80w already permanently fitted?


yep, if the panels are the same voltage you can just tag them in parallel if you set the wiring up right.



I hadn't realised that. Is there a simple explanation as to why this is the case? I'd always thought that as long as the isolator was open a rear connection to the aux also took care of the crank battery

The older traxide units only sense the crank battery voltage, while connected whatever you do to the aux battery in terms of charge or draw you also do to the crank battery. IF however it disconnects and you are charging the AUX battery the crank battery (which also has your parasitic drains for the vehcile and the traxide on it) get no charge and keeps going flat.




Regulators
If using two separate and not permanently mounted arrays & regardless of their physical proximity to one another is there any reason why both arrays can't feed into a single reg of the correct capacity?

Yes and no.
so long as the arrays are the same and rigged appropriately (electrically speaking) then yes.

If the arrays differ then no. (for varying definitions of how badly no, from just not as effecient no to smoke releasing burn your vehicle down no)




Single panel size
We've been talking about single 80w by default but originally I was hoping to get fold up / blanket type arrays but they're not available locally. Then I saw the local 20w and thought I'd customise it into a blanket configuration replacing the glass with semi flexible plastic similar to that used for laminating ID cards and the like. However after nearly trashing one I don't think it'll be possible to separate the cells from the glass. So that brings me to the idea of radically cutting down or replacing the aluminium frames and settling for pairs of panels configured in the suit case style. It might even be possible for me to trim the glass off around the margins to further reduce their size

No. go on ebay,wish, geek and find someone that will ship. Failing that buy some quality ones near someone who is friendly have them sent to them and then get them sent to you.



Its not definite as I've yet to sit and compare the dimensions of the various watt size panels but I'm leaning toward using multiple pairs of 20w panels in both the stage 1 & stage 2 arrays. Its easier to pack small pairs than larger singles or larger pairs and smaller pairs will be easier to position and manoeuvre.

Any thoughts and suggestions would be most welcome

the idea for the single 20w panel unregulated was for when you park the vehicle in a lock up garage and want just enough to stop the batteries going flat. if you park it in the sun and have an 80w panel on the roof then the 20w panel is redundant for that purpose.

[Ooops]

If you're daily driving you dont even need the panel, with a traxide and ~60Ah worth of aux battery you should be good for 24 hours in a spot without the batteries getting flat.

In the context I used, I meant to and from work, shops etc as opposed to recreationally.

I think the overall time spent driving is the key here.
I have the standard, single yellow top 55aH Optima fitted as an aux.

If I'm not using the fridge, just doing short trips of 30mins total for a day for a couple of weeks, its not enough to keep things up together and if after this I park up for four or five days it'll be at the limit. I have had it go flat on me, probably left a light on

For recreational trips where I'm driving for four ish hours a day in one hit I have the fridge turned way down while travelling and set to chill when stationary and it normally lasts all night. This would be the comfort zone for the system.

I can't remember having ever tried it 24hrs stationary so I can't speak to that but I'd imagine that with proper management of the fridge it'd work

At the other extreme, I recently did a three month stint using the fridge to keep bottles of water cold for the crew. Daily driving was down to 1.5 hrs each way. Fridge was set to freeze while travelling and chill while stationary. Ambient was high 40?C. The fridge was being opened a lot and topped up with new bottles as the cold ones were removed.

On the days where the car was driven for short stints all day the fridge went the distance

On the days where the work was in one spot and the car was parked up the fridge didn't last a full ten hours during the day and most mornings it was off when I unlocked the car.

In the latter situation I imagine that a panel or perhaps more aux battery would have really helped


Fit the panel lenghtways in the middle of the rack at the rear in a slide out mount with QD weather proof fittings and make an extension cord to suit.

Unfortunately for this situation I bought a beautiful low profile Prospeed rack, cost a fortune to get it to me, it looks like a work of art and fits like a glove with the result that there is zero clearance for storage under the rack.

If I'd gone for a front runner at a half the price I could have slid it under

Any mods would have to be above the rack's floor. In their current frames the panels would sit 5mm above the side rails so not awful but then things would have to sit on top of that.

A quick play on the computer suggests that 4x 20w will fit across the front, above the sun roof so there's a starting point


MAke up a protective ... frame for the panel ... to load ontop
.... make a pod roof case .... and incorperate the panel into the topshell.
Good ideas, I'll have to get used to thinking a bit more outside of the box :Rolling:

Actually I think your earlier comment might be the answer

If you're daily driving you dont even need the panel, with a traxide and ~60Ah worth of aux battery you should be good for 24 hours in a spot without the batteries getting flat.

When work and day to day things are happening I tend to cover a lot of miles so lots of time for the alternator to be charging. So instead of a permanently mounted panel can I benefit in a significant manner from fitting my spare 50Ah Optima as a second aux battery? Or from fitting a significantly larger single aux battery?

If I understood the calculations you did for me earlier it should gain me an additional 24hrs of fridge time based on 50?C ambient 3 aH/hr x 24hrs @ 70% duty cycle = 50.4aH

The fitting could be on a temporary, as required basis or a permanent installation. The stage 1 80w of folding panels would be carried as required, and a dedicated 20w maintenance panel installed at home. And no messing with my da Vinci inspired rack :D


The older traxide units only sense the crank battery voltage, while connected whatever you do to the aux battery in terms of charge or draw you also do to the crank battery. IF however it disconnects and you are charging the AUX battery the crank battery (which also has your parasitic drains for the vehcile and the traxide on it) get no charge and keeps going flat.
:BigThumb: yep I've had that happen recently


for varying definitions of how badly no, from just not as effecient no to smoke releasing burn your vehicle down no
:eek:


No .... Failing that buy some quality ones near someone who is friendly have them sent to them and then get them sent to you.
The local panels & regs are Copex & labelled "made in Germany". Being a sceptic I highly doubt they are unless they're seconds. However the figures this one is putting out do seem ok to my inexperienced eye. I haven't published them yet as I keep fiddling with things but I will as soon as I get every thing squared away.

The reg being offered is a Copex VS1024BN PWM at AU$110


the idea for the single 20w panel unregulated was for when you park the vehicle in a lock up garage and want just enough to stop the batteries going flat. if you park it in the sun and have an 80w panel on the roof then the 20w panel is redundant for that purpose.
Sorry, I had a blonde moment there

Well it looks like I've got home work

[Blknight.aus]

In the context I used, I meant to and from work, shops etc as opposed to recreationally.

I think the overall time spent driving is the key here.
I have the standard, single yellow top 55aH Optima fitted as an aux.

If I'm not using the fridge, just doing short trips of 30mins total for a day for a couple of weeks, its not enough to keep things up together and if after this I park up for four or five days it'll be at the limit. I have had it go flat on me, probably left a light on

For recreational trips where I'm driving for four ish hours a day in one hit I have the fridge turned way down while travelling and set to chill when stationary and it normally lasts all night. This would be the comfort zone for the system.

I can't remember having ever tried it 24hrs stationary so I can't speak to that but I'd imagine that with proper management of the fridge it'd work

At the other extreme, I recently did a three month stint using the fridge to keep bottles of water cold for the crew. Daily driving was down to 1.5 hrs each way. Fridge was set to freeze while travelling and chill while stationary. Ambient was high 40?C. The fridge was being opened a lot and topped up with new bottles as the cold ones were removed.

On the days where the car was driven for short stints all day the fridge went the distance

On the days where the work was in one spot and the car was parked up the fridge didn't last a full ten hours during the day and most mornings it was off when I unlocked the car.

In the latter situation I imagine that a panel or perhaps more aux battery would have really helped

for the first day or 2 yes but then you not only have to run the load but also charge all of the battery capacity which means running the engine longer.




Unfortunately for this situation I bought a beautiful low profile Prospeed rack, cost a fortune to get it to me, it looks like a work of art and fits like a glove with the result that there is zero clearance for storage under the rack.

If I'd gone for a front runner at a half the price I could have slid it under

Any mods would have to be above the rack's floor. In their current frames the panels would sit 5mm above the side rails so not awful but then things would have to sit on top of that.

yep, what you want to do is make up a sub frame that bolts onto your existing panel you build the frame so your panel is removable from the frame by sliding it in and out and other permanent items have fixed easy to use mounts that dont require use of strapping to hold them in



A quick play on the computer suggests that 4x 20w will fit across the front, above the sun roof so there's a starting point


Good ideas, I'll have to get used to thinking a bit more outside of the box :Rolling:

Actually I think your earlier comment might be the answer


When work and day to day things are happening I tend to cover a lot of miles so lots of time for the alternator to be charging. So instead of a permanently mounted panel can I benefit in a significant manner from fitting my spare 50Ah Optima as a second aux battery? Or from fitting a significantly larger single aux battery?

yes but as above bigger battereis need more charging once they go flat. if you only ever have to make 1 or 2 days its the cheapest way of going and over time short drives or a small charger/panel will bring them up (and I know plenty of guys with 200Ah battery systems on campers that go out on a weekend and then just plug into a small solar panel for 2 weeks or put on a cheapy 2 amp charger onto the camper till they go out on the next pay weekend.



If I understood the calculations you did for me earlier it should gain me an additional 24hrs of fridge time based on 50?C ambient 3 aH/hr x 24hrs @ 70% duty cycle = 50.4aH

The fitting could be on a temporary, as required basis or a permanent installation. The stage 1 80w of folding panels would be carried as required, and a dedicated 20w maintenance panel installed at home. And no messing with my da Vinci inspired rack :D


:BigThumb: yep I've had that happen recently


:eek:


The local panels & regs are Copex & labelled "made in Germany". Being a sceptic I highly doubt they are unless they're seconds. However the figures this one is putting out do seem ok to my inexperienced eye. I haven't published them yet as I keep fiddling with things but I will as soon as I get every thing squared away.


Bad man... you should also publish the things you tried and the outcome you got from them. That way the info is there for others who might want to try something similar or need a variation thereof.




The reg being offered is a Copex VS1024BN PWM at AU$110


Sorry, I had a blonde moment there

Well it looks like I've got home work


yep thats the problem with asking good questions, good answers lead to more questions.

[DiscoMick]

If it helps I'm mounting my 80 watt panel across the front of a Rhino Rack platform and the bars of the platform are thicker than the height of the panel so I will still be able to lay long items on top of the bars and they won't touch the panel below them.
My solar came from an ebay seller in Sydney but was made in China. A 10A regulator was supplied with the panel.
It will be connected to the Defender's starting battery which is linked by a Traxide and a thick cable with 60 amp fuses both ends to a 120 amp AGM stored in the rear under the back of the drawers.
It will power an Evakool 30 litre fridge-freezer in the rear.
So I would expect to get about three days running out of this battery setup plus the boost from the solar, so certainly at least 5 days, plus driving.
I don't see any need for a DC-DC charger with this setup.
So this is vagely similar to your plan, I think. Hope that helps.

Sent from my SM-G900I using AULRO mobile app

[Ooops]

I imagine that ..... more aux battery would have really helped

for the first day or 2 yes but then you not only have to run the load but also charge all of the battery capacity which means running the engine longer.

.... if you only ever have to make 1 or 2 days its the cheapest way of going

That was the context I was talking about, remaining stationary for two days, three at the absolute tops and using 100Ah of aux battery to do so. No need to mount panels or mess with the rack.

Would adding 1x 50Ah to the existing 50Ah be sufficient for 48hrs?


bigger battereis need more charging once they go flat.

Which begs the questions

how long does it take a D3 alternator to fully charge a 50Ah battery from 11.6v / 25% SOC? (I chose 11.6v because that's how Tim's ABG-25 comes shipped. But it can be set to 11.8v, 12.0v and 12.3v.)


How is that charging period affected by adding an additional 50Ah battery?


if you only ever have to make 1 or 2 days its the cheapest way of going

...... just plug into a small solar panel for 2 weeks or put on a cheapy 2 amp charger onto the camper till they go out on the next pay weekend.

So my thought was;
1 fridge for 48 hrs stationary = an additional 50Ah battery, stand alone if necessary
1 fridge for 1 week stationary = 80w portable plus the same additional 50Ah battery
2 fridges for 1 week stationary = 80w plus 80w portable plus the same additional 50Ah battery


Bad man... you should also publish the things you tried and the outcome you got from them.
I'm suitably chastised though in my defence I was referring to finding the right place to get the panels to work at their best so lots of varied readings, down time changing connectors and fittings and the SC80 shutting down and the readings only applying to charging the aux battery:blush:

However here are the figures for the last 29hrs 0700 through 1300hrs the following day
1.01A, 13.40V, 13.5W, 12.18Vm, 1.21Ap, 0.17Kwh, 13.41Ah
12.66V measured at the battery at 1300 hrs. How does that rate?

[Blknight.aus]

That was the context I was talking about, remaining stationary for two days, three at the absolute tops and using 100Ah of aux battery to do so. No need to mount panels or mess with the rack.

Would adding 1x 50Ah to the existing 50Ah be sufficient for 48hrs?


on paper with a traxide yes based on your fridges higherduty cycle but the numbers are close. I would go with yes based on new batteries maybe as they age and no if they have lost more than about 10% of their capacity or have developed a higher rate of self discharge.




Which begs the questions

how long does it take a D3 alternator to fully charge a 50Ah battery from 11.6v / 25% SOC? (I chose 11.6v because that's how Tim's ABG-25 comes shipped. But it can be set to 11.8v, 12.0v and 12.3v.)


How is that charging period affected by adding an additional 50Ah battery?


I'm guessing a little here and I'm going to go with about 2 hours which would more or less double for the extra battery. Sadly its not that simple due to the nature of alternators and charging/discharging batteries




So my thought was;
1 fridge for 48 hrs stationary = an additional 50Ah battery, stand alone if necessary

That should work

1 fridge for 1 week stationary = 80w portable plus the same additional 50Ah battery

That should work but depending on how well you can (or more accurately cant) position the panel might be marginal depending on if you have any other parasitic loads


2 fridges for 1 week stationary = 80w plus 80w portable plus the same additional 50Ah battery

This would be workable assuming you dont have extra unplanned loads with the second frdige.




I'm suitably chastised though in my defence I was referring to finding the right place to get the panels to work at their best so lots of varied readings, down time changing connectors and fittings and the SC80 shutting down and the readings only applying to charging the aux battery:blush:

However here are the figures for the last 29hrs 0700 through 1300hrs the following day
1.01A, 13.40V, 13.5W, 12.18Vm, 1.21Ap, 0.17Kwh, 13.41Ah
12.66V measured at the battery at 1300 hrs. How does that rate?

Of just as much interest is what you're doing as part of your experiments.

and for a 20w panel those numbers are pretty good and if they repeat reliably you know what your base input per panel is.

[Ooops]

If it helps I'm mounting my 80 watt panel across the front of a Rhino Rack platform and the bars of the platform are thicker than the height of the panel so I will still be able to lay long items on top of the bars and they won't touch the panel below them.
Thanks DM you gave me a lot of food for thought, in fact a whole afternoon's worth:D

I looked at this yesterday from the perspective of putting it on top and wrote it off but your message got me to reevaluate the options. I've uploaded a couple of photos to illustrate the issues

There's is room to fit panels under the rack :banana:
but the depth of the frame would have to be reduced, not a problem
for a large single panel the rack would need to come off for the installation
multiple smaller panels could be fitted with the rack in place
cells would be partially blocked by the cross bars
it would be a semi permanent installation & not possible to demount the panel(s) in camp
A permanent, non demountable install means the vehicle has to be parked in full sun. I have to do this 99.9% of the time any how but in other parts of the world .....
the rack would have to be unloaded to expose the panels
because of the rack's design removable flooring would have too be used to protect the glass
the panels would lay flat at all times, angling towards the sun would not be possible

None of the above are impossible but I can't help feeling that having to unload the rack to expose the panel(s) means its going to get a lot less use that it otherwise would

A twist to the under rack would be to lay a raised ply floor and inlay the panel, the floor would need to be 50mm thick and most of the other issues would still exists

Dave's idea with the frames is more obtrusive, (remember this is a da Vinci rack), but far more practical. However if a panel was to be carried under a frame it wouldn't be ready for instant use and would never see the sun unless demounted and assembled. Its likely that it could only be accessed from the side of the vehicle because of the shark fin antenna on the rear

It seems like a suitcase panel would require a lot less messing around.:wasntme:

But as Dave has suggested if a panel was to be carried on top of a frame it would be ready for instant use, constantly visible to the sun and it could be angled. It could also be made demountable. A frame that went over the accessories instead of the other way around would provide the accessories with security and protect them from UV allowing for permanent carry.

An example might be a shallow full width frame at the the back. The frame might house maxtrax and rope which because of their shape could be accessed from the rear of the vehicle. The top of the frame would support an 80w across the width of the vehicle. The panel would overhang the rack 3cm on each side but not the overall vehicle width

But it still seems to me like a suitcase panel would require a lot less messing around and when required easily fixed to the roof for as long as required ...... I'm just saying :D:wasntme:


.... with 60 amp fuses both ends
Why fuses at both ends?


..... 80 watt panel .... a 120 amp AGM
..... an Evakool 30 litre fridge-freezer ..... three days ... out of this battery setup, so ... at least 5 days, plus driving
DM is this a work in progress or have you had a chance to give it a good spanking in real time?



I don't see any need for a DC-DC charger with this setup. From what I've read most of the guys who truely know the 'magic? of the traxide install agree with you. I am not one of those who "truly know" so no taking me to task over it:D


So this is vagely similar to your plan, I think. Hope that helps.
Indeed it is mate and many thanks for sharing. If you haven't already run it let us know how your system performs in real time

[Ooops]

100Ah sufficient for 48 hrs?

yes based on new batteries
Awesome


I'm guessing a little here and I'm going to go with about 2 hours which would more or less double for the extra battery
Awesome, most of my recreational journeys require a minimum of 3 hours each way. Might be a bit sketchy for my last project which was 1.5 hours each way but next time I'll have panels with me


for a 20w panel those numbers are pretty good Wow, perhaps they are genuine then. It'll be interesting to see what the voltage settles at


Of just as much interest is what you're doing as part of your experiments. Well the only other thing that might be of interest is that I split the feed from the panel. I ran a cable with a watts up on it that's conveniently located for charging the car and another longer cable to the work shop with another watts up on it to use with the batteries I have stored there. It'll make keeping every thing up together some more convenient.

What I'm looking forward to seeing is what happens if I connect the D3 and a workshop battery at the same time. I'm guessing it'll work in the same way and be effective but at a lesser and slower rate.

I haven't connected the work shop cable to anything other than the watts up and won't until all testing with the D3 has been completed otherwise I won't have a base line to work from. It'll be interesting to see what the D3 float voltage ends up at. What I did notice is that the watts up on the longer cable gets a very slightly higher voltage at the battery read out at .01 difference. [edit: I checked this morning and the 5m cable reads 13.39 while the 15m cable reads 13.97v]

1 fridge for 48 hrs stationary = an additional 50Ah battery, stand alone if necessary
1 fridge for 1 week stationary = 80w portable plus the same additional 50Ah battery
2 fridges for 1 week stationary = 80w plus 80w portable plus the same additional 50Ah battery
[QUOTE=Blknight.aus;2609812] That should work ... might be marginal depending on if you have any other parasitic loads

Dave, lads thanks so much for all of this I now have a logical plan to work to and a much improved, if still fairly shallow, understanding of the subject. I'm extremely grateful for every one's input & patience.

My next search will be on panel wiring and third battery installations :D

[Ooops]

Battery connections

I forgot to ask about the correct way to connect a panel or a reg to the D3

I understand that incorrect connections interfere with the D3's battery monitoring system and that accessories should not be connected directly to the negative terminal but to an earth stud instead.

Does this also apply to panel and regulator connections?

[DiscoMick]

My vehicle system is a work in progress, but it is based on experience with our camper trailer, which has an Engel 40 litre fridge, a 105 Ah AGM and an 80 watt folding panel, so with a smaller fridge and larger battery in the vehicle, I am confident it will work.
We have camped for a week with the camper OK. After running the fridge overnight the solar has usually replaced what was used by mid-morning and then you just need to keep it charging for as long as possible.
The main disadvantages of a folding panel are you have to actually set them up and they can be stolen. An advantage is the panels can be moved several times a day to maximise solar input.
Having the panel on the roof should be similar to laying a panel on the ground. The angle might not be perfect, but up on the roof it should get some sun all day.


Sent from my SM-G900I using AULRO mobile app

[Ooops]

Having the panel on the roof should be similar to laying a panel on the ground. The angle might not be perfect, but up on the roof it should get some sun all day.

:BigThumb:

DM What was the reason for installing 2x 60amp fuses at both ends of the cable?

[Ooops]

Drove today for three hours, 1.5hrs each way. Just before home I stopped for fuel. When I got home, before connecting the solar I measured voltage at the crank battery and it was only 12.3V.

Is this normal or do I have issues?

[Anth]

That's a bit low. It should be between about 12.6 - 12.8v. Was everything off? Headlights, stereo? How old is your crank battery?

1998 Disco 1 300tdi no edc no abs
1995 Disco 1 v8i dual fuel RIP

It's not leaking oil, it's bleeding power.

[drivesafe]

I measured voltage at the crank battery and it was only 12.3V.

Hi Magnet, if that was the voltage just after turning off your motor, say within a few minutes, and you had nothing turned on, then you definitely have an issue.

All lead acid batteries, even when they are stuffed, will have a surface voltage reading above 12.7v, straight after turning the motor off.

Try starting your motor and then measuring the voltage at your cranking battery.

This should be anything above 13.5v.

If it is not above 13.5v, then you have a problem and it is most likely your alternator, but it could also be one of your batteries on it's way out.

[DiscoMick]

:BigThumb:

DM What was the reason for installing 2x 60amp fuses at both ends of the cable?

The auto electrician reckoned it was necessary to stop any short as close to the battery as possible.

Sent from my SM-G900I using AULRO mobile app

[Ooops]

Hi Magnet, if that was the voltage just after turning off your motor, say within a few minutes, and you had nothing turned on, then you definitely have an issue.

All lead acid batteries, even when they are stuffed, will have a surface voltage reading above 12.7v, straight after turning the motor off.

Try starting your motor and then measuring the voltage at your cranking battery.

This should be anything above 13.5v.

If it is not above 13.5v, then you have a problem and it is most likely your alternator, but it could also be one of your batteries on it's way out.
In retrospect I'm not sure that the car was asleep as I was in and out of the doors but it was turned off and ignition key out.
drivesafe I'm getting a steady 14.3v at start up, the revs usually drop off a little when it warms up but I didn't have time to wait for that. I'll take a reading at normal revs a little later. Both Optima were fitted around June 2014

For connecting the panel to the crank battery should the negative go an earthing point on the body or is it ok to clamp directly to the battery?

[Ooops]

Back tracking a little .....


For charging..

Batteries have lots of numbers around them and cover lots of details, the 2 that count most for basic charging are 1. the max charge rate (amps) and 2. the max charge voltage.


some of the batteries have damaged data stickers where bits of info can't be read
In cases where the info isn't to hand is there a convention or a formula or that can be used to calculate the max charge rate (amps) and the max charge voltage?

[Ooops]

The auto electrician reckoned it was necessary to stop any short as close to the battery as possible.
Sent from my SM-G900I using AULRO mobile app

Thanks. Using one I understand but I'm still curious as to the benefit of using two. I'm not saying its wrong, I'm just trying to learn some thing.


If it helps I'm mounting my 80 watt panel across the front of a Rhino Rack platform
Any chance of a piccy DM?

[drivesafe]

Hi again Magnet, and 14.3v is fine, so your alternator is working.

If you had doors open and had had them opened for a while, then 12.3v is average.

So again, not any real problem.

As far as charging any lead acid battery goes, if you make sure the charge voltage does not go over 14.4v, you will fully charge any type of lead acid battery and will not risk damaging any type of lead acid battery if you leave the charge source on the battery for any length of time.

NOTE, the 14.4v charge voltage applies to Battery chargers, DC/DC devices and solar regulated charging, and all these types of charging devices should go into FLOAT mode once the batteries are fully charged.

Alternator charging can safely go as high as 14.7v and will not damage batteries because you do not drive long enough to cause a problem.

[Ooops]

14.3v is fine, so your alternator is working.

If you had doors open and had had them opened for a while, then 12.3v is average.



Thanks for the peace of mind

What were your thoughts on connecting the solar panel to the crank battery? Should the negative go an earthing point on the body or is it ok to clamp directly to the battery?

[Aaron IIA]

Thanks. Using one I understand but I'm still curious as to the benefit of using two. I'm not saying its wrong, I'm just trying to learn some thing.


If you are joining in a second battery, you need a fuse at both ends of the joining wire. If it rubs through and shorts out, you need it to isolate at both ends, as you have a power supply at both ends.

Aaron

[Ooops]

If you are joining in a second battery, you need a fuse at both ends of the joining wire. If it rubs through and shorts out, you need it to isolate at both ends, as you have a power supply at both ends.

Aaron
Thank you Aaron

[Blknight.aus]

Back tracking a little .....



some of the batteries have damaged data stickers where bits of info can't be read
In cases where the info isn't to hand is there a convention or a formula or that can be used to calculate the max charge rate (amps) and the max charge voltage?


not really,,,

theres a rule of thumb for field work that I use but its rough and ready.

max voltage for any kind of lead acid battery is 14.5v (field rule) on a low charge rate

optimal charge rate is the 10 hour rate (which is how many amps it takes to flatten the battery in 10 hours and is worked out by mathing the AH value or mathing the RC into an AH rate and then working that AH rate

the RC is how many minutes the battery can pump 25A.. convert the RC to hours, mulitply it by 25 and thats how many amp hours are in the battery divide that number by 10 to get the 10 hour rate.

for example battery with an RC of 90 will push 25 amps for 1.5 H

1.5hx25A=37.5Ah

37.5Ah/10h=3.75A. (which is nearly exactly what it takes to drive an engle so an engel with a 100% duty will eat that battery in 10 hours (it wont it lasts longer because peurkets law)

so 3.75 Amps or near enough 4 amps is the optimal rate of charge for that battery

max charge rate I normally recommend is roughly double that BUT remember most chargers will self regulate on the voltage level so the battery looks after itself.

The best bet for the info is just to look up the battery spec online from its manufacturer.


Winding back a little to your comment about genuine panels.

most panels make what they say, to start with. the Quality of a panel is how long it keeps its output within 10% or so of its max power.

panels degrade a little bit quite quickly, then enjoy a fairly good life span before slowly (and then exponentially) beginning to drop their out put.

[DiscoMick]

Thanks. Using one I understand but I'm still curious as to the benefit of using two. I'm not saying its wrong, I'm just trying to learn some thing.


Any chance of a piccy DM?

Its not mounted yet, but these are the panel and platform.
I thought about mounting it directly to the bars, but I already had the platform and bars so its easy to use it and cover more roof. Just need some angle brackets and clamps.
I've already wired up the Defender so its ready to plug in.
Incidentally, I don't know about the smart alternator in D3/4s which vary their output depending on load, but my Defender just churns out a steady 14 volts, which is perfect for charging batteries.
I recommend before heading away you use a good battery charger overnight so everything is 100% charged, as driving may only take your batteries to 80-90%. The last 10-20% needs a slow charge from a multi-stage charger.


Sent from my SM-G900I using AULRO mobile app

[DiscoMick]

not really,,,

theres a rule of thumb for field work that I use but its rough and ready.

max voltage for any kind of lead acid battery is 14.5v (field rule) on a low charge rate

optimal charge rate is the 10 hour rate (which is how many amps it takes to flatten the battery in 10 hours and is worked out by mathing the AH value or mathing the RC into an AH rate and then working that AH rate

the RC is how many minutes the battery can pump 25A.. convert the RC to hours, mulitply it by 25 and thats how many amp hours are in the battery divide that number by 10 to get the 10 hour rate.

for example battery with an RC of 90 will push 25 amps for 1.5 H

1.5hx25A=37.5Ah

37.5Ah/10h=3.75A. (which is nearly exactly what it takes to drive an engle so an engel with a 100% duty will eat that battery in 10 hours (it wont it lasts longer because peurkets law)

so 3.75 Amps or near enough 4 amps is the optimal rate of charge for that battery

max charge rate I normally recommend is roughly double that BUT remember most chargers will self regulate on the voltage level so the battery looks after itself.

The best bet for the info is just to look up the battery spec online from its manufacturer.


Winding back a little to your comment about genuine panels.

most panels make what they say, to start with. the Quality of a panel is how long it keeps its output within 10% or so of its max power.

panels degrade a little bit quite quickly, then enjoy a fairly good life span before slowly (and then exponentially) beginning to drop their out put.

Can I ask if your very helpful calculations are based on the fridge running constantly or cycling on and off?

Sent from my SM-G900I using AULRO mobile app

[Blknight.aus]

Sure you can.

in that example that with the compressor never cycling off (hence 100% duty cycle)

if you have a roughed out average of your duty cycle divide the estimated life by the decimal percentage of your duty cycel.

IE if you have a predicted time of 10 hours at 100% duty but you know you only average a 70% duty cycle divide by .7

10/.7=14.285(near enough)


IF you're going to play with my field calc stuff remember that they are all based on ignoring perkerts law or having it set up so that it falls in your favor. (which means you get more than your calcs show and is the fudge factor and why I call them field calcs)

theres a bunch of other little things you can do or should be aware of

as the voltage drops the fridge draws more amps, or the duty cycle increases slighty (depending on your fridges setup)

panels and regulators only put out whats needed and the rest evaporates if its not needed. if you plan on charging things its best to do it when the panels are outputting their maximum, perversely, this is also usually the worst time to be charging batteries (heat)

a gang of smaller panels and batteries is better than a single big one for both redundancy and taking care of puekert BUT its more maintenance intensive, costs more and is harder to setup properly.

A single large unit is easier and cheaper but offers no redundancy.

dont oversize the battery capacity, you need just enough to get you from charging to charging and some reserve. higher capacity batteries that are flat need more time to charge and usually higher charging currents.

dont discount how much a small wind turbine will put back into your batteries small wind turbines are now cheaper than some panels and while they dont match up Watt for Watt, the wind turbine can work at night when your loads are lightest.

Fuse the panels at Amax as near to the panel as possible
fuse the regulator at the regulator, the battery and the load output (if it is handling your load switching
Always double fuse leads between batteries (as close to the positive as possible assuming negative earth)
Regulators go near batteries and like to be cool, panels get to be in the sun, like to be kept cool but dont get a whole lot of say about that.

best of luck.

[Ooops]

not really,,,
theres a rule of thumb for field work that I use but its rough and ready.
.... mathing the RC
sorry to ask but RC?



The best bet for the info is just to look up the battery spec online from its manufacturer.
:D

[Ooops]

A very useful summary, thanks



...... dont oversize the battery capacity, you need just enough to get you from charging to charging and some reserve.
What % reserve would you recommend?



Regulators go near batteries and like to be cool

So on a permanently mounted roof panel in side the vehicle would be best, but if necessary could it survive in the engine bay?

Appropriately sized cable and within acceptable voltage drop being a given, as its ok to plug solar into the rear Anderson can I take it that a couple of meter cable run between reg and battery is ok?



dont discount ... a small wind turbine
the wind turbine can work at night when your loads are lightest.

Great suggestion, any ideas on sources of info?

[Ooops]

Its not mounted yet, but these are the panel and platform.

Thanks mate

[DiscoMick]

My regulator is in the battery box under the front passenger seat.
The comment about wind generators is interesting. I've seen the ones on yachts and thought they would be a good idea for camping as it is often windy at night. What sort of costs are we talking for a compact one? Are they just plug and play?

Sent from my SM-G900I using AULRO mobile app

[Blknight.aus]

sorry to ask but RC?

:D

Reserve capacity.

other numbers to watch out for that can be useful are
CCA (cold cranking amps)
Ah (amp Hours)
MCA(Marine cranking amps
CA (cranking amps)
MAX/Min V (maximum and minimum Voltage of the battery, usually an unloaded voltage)
Charge rate (usually for batteries designed to be charged at by fixed current)



A very useful summary, thanks


What % reserve would you recommend?



Something in the positive numbers region. Without knowing all the details its hard to give a direct number and theres a bunch of different ways of achieving reserve. In my case (and my setup is similar to what youre doing, I think.) My reserve is actually my starting battery because I dont have a traxide, However I dont suggest you try that for a few reasons.
1. you dont yet know that I also carry a jump pack that can start my car with no batteries in it. (mainly used for short term power away from the vehicle and it has its on dedicated one way charge lead so its never flat)
2. you might have guessed that as my vehicle is a manual disco1 that I probably know what to do to get it to start without a battery
3. you dont know that when I park up when Im going to use the batteries more than over night I always park up so I have enough room to get a bump start to work (because my answer to the landrover dilemma of do i park on the hill in case the starter fails or on the flat in case the park brake does is to park on the hill and chock the wheels.)

My uneducated answer to any "how much reserve" is almost invariably 30%





So on a permanently mounted roof panel in side the vehicle would be best, but if necessary could it survive in the engine bay?


yes, and yes. But wherever you mount it if it has the option for battery temperature sensing then its a smart idea to fit that up.


Appropriately sized cable and within acceptable voltage drop being a given, as its ok to plug solar into the rear Anderson can I take it that a couple of meter cable run between reg and battery is ok?


Yes, its not utterly ideal but its a good compromise. the setup in my system has the panel up over the front of the roof (in the stepped down section so it doesnt interfere with my roof height) the regulator is mounted in the roof at the rear of the vehicle, the rear power distribution is handled in the right hand rear light cluster area and the battery is up the left front of the vehicle with the power cable run from the right rear lights up through the roof down the drivers A pillar through under the dash to the passangers side, out a gromit in the fire wall and along the left wing to the primary fuse into the battery. While that sounds contrary to the advice Ive given theres an anderson plug at the right rear that is setup to accept a direct connection battery tank when I need to extend my storage capacity or run high current drain gear as well as being able to accept external charging. The cable that runs the length of the vehicle is sufficiently rated that it can be used to run winches.



Great suggestion, any ideas on sources of info?

Google?

normally Id reccoemend jaycar for something off the shelf thats not a budget breaker but your in the wrong part of the planet for them.

[Aaron IIA]

sorry to ask but RC?

:D


the RC is how many minutes the battery can pump 25A.. convert the RC to hours, mulitply it by 25 and thats how many amp hours are in the battery divide that number by 10 to get the 10 hour rate.

for example battery with an RC of 90 will push 25 amps for 1.5 H

1.5hx25A=37.5Ah

That sould help you. RC is reserve capacity. It is measured in minutes. Your battery should have any of three ratings written on it's top. For deep cycle batteries, xxxAhr, amp hours. For cranking batteries, xxxCCA, cold cranking amps and RC, reserve capacity.

Aaron

[DiscoMick]

Reserve capacity.

other numbers to watch out for that can be useful are
CCA (cold cranking amps)
Ah (amp Hours)
MCA(Marine cranking amps
CA (cranking amps)
MAX/Min V (maximum and minimum Voltage of the battery, usually an unloaded voltage)
Charge rate (usually for batteries designed to be charged at by fixed current)



Something in the positive numbers region. Without knowing all the details its hard to give a direct number and theres a bunch of different ways of achieving reserve. In my case (and my setup is similar to what youre doing, I think.) My reserve is actually my starting battery because I dont have a traxide, However I dont suggest you try that for a few reasons.
1. you dont yet know that I also carry a jump pack that can start my car with no batteries in it. (mainly used for short term power away from the vehicle and it has its on dedicated one way charge lead so its never flat)
2. you might have guessed that as my vehicle is a manual disco1 that I probably know what to do to get it to start without a battery
3. you dont know that when I park up when Im going to use the batteries more than over night I always park up so I have enough room to get a bump start to work (because my answer to the landrover dilemma of do i park on the hill in case the starter fails or on the flat in case the park brake does is to park on the hill and chock the wheels.)

My uneducated answer to any "how much reserve" is almost invariably 30%


yes, and yes. But wherever you mount it if it has the option for battery temperature sensing then its a smart idea to fit that up.

Yes, its not utterly ideal but its a good compromise. the setup in my system has the panel up over the front of the roof (in the stepped down section so it doesnt interfere with my roof height) the regulator is mounted in the roof at the rear of the vehicle, the rear power distribution is handled in the right hand rear light cluster area and the battery is up the left front of the vehicle with the power cable run from the right rear lights up through the roof down the drivers A pillar through under the dash to the passangers side, out a gromit in the fire wall and along the left wing to the primary fuse into the battery. While that sounds contrary to the advice Ive given theres an anderson plug at the right rear that is setup to accept a direct connection battery tank when I need to extend my storage capacity or run high current drain gear as well as being able to accept external charging. The cable that runs the length of the vehicle is sufficiently rated that it can be used to run winches.


Google?

normally Id reccoemend jaycar for something off the shelf thats not a budget breaker but your in the wrong part of the planet for them.

Jaycar is online.
https://www.jaycar.com.au/

Sent from my SM-G900I using AULRO mobile app

[Ooops]

I've had the set up running without interruption for about a week, here are the readings

14.2w 14.07v 1.08A
1.18Ap 3.33Vm 0.93Kwh
71.1Ah

I've noted during that time

when there's no input from the panel the batteries don't exceed 12.3v ish

the panel seems to max its input at 13.5v and rarely achieves 14v

3.3Vm is a bit weird. I think it can be ignored as I believe it came from a connection I made to a battery on the bench before connecting up to the D3

I've disconnected a spur I had running to the workshop and reduced the cable run between the panel and the crank battery to about 1.5m and there's no change in the 13.5v ish input
I've just checked the panel disconnected and its putting out 20.28v
There's nothing else connected or turned on in the car and AFAIK its been asleep so I can't think what else could be taking power

So why is it limited to 14v or less input and why are the batteries only achieving 12.3v ish?

[Blknight.aus]

internal discharge in one or more of the batteries.

a diode on one winding of the alternator going leaky but not completely failed yet.

a part of the vehicle not going to sleep properly (security system that stays on listening for the right code because someone has a something transmitting hash on just the right freq)

a corroded joint thats making to earth on something thats permanantly powered.

a relay that drives something thats sticking in the on position even though the relay is de-energised.

something installed aftermarket thats interferering with vehicle operation or is in itself a drain (some cheap USB sockets draw up to 500mA if your using them or not)

[Ooops]

Cheers Dave

internal discharge in one or more of the batteries.
How do I check for this?


a diode on one winding of the alternator going leaky but not completely failed yet.
would this have an effect without the engine running?


a relay that drives something thats sticking in the on position even though the relay is de-energised.
I've been having issues with the suspension compressor, recently replaced but showing an intermittent fault, so well worth a check. How does one check a relay's function?


something installed aftermarket thats interferering with vehicle operation or is in itself a drain (some cheap USB sockets draw up to 500mA if your using them or not)Hmm, I recently installed an anchor USB hub but it was on a key controlled circuit. I'll disconnect it and see if it makes any difference.

[Blknight.aus]

to check for internal self discharge the simple way is to drop the terminals off do a load check on the battery, leave it a week and do it again. if the test varies the battery is dying

a leaky diode will have an effect as the output terminal is live to to the battery all the time.

pull the relay measure for resistance across the solenoid terminal to all other terminals then check from the common terminal to both the NC and NO terminal then from NC to NO terminals.

common to NO should show infinite resistance Common to NC should show zero and NO to NC should show infinite.

I have 4 outlets that are permanenatly on the aux battery for emergancy use and charging if I get desperate or want to plug in a trickle charger. My USB's are very old and have a contact switch built into the socket that controls the 12V supply, if nothing is plugged in they are turned off.

[Ooops]

Does it require specialist equipment or is there a DIY method for load testing the batteries?

I'll pull the relay tomorrow and check it as desscribed

I'm not that happy with the USB mod so it'll come out. I'll keep your of fitting a switch in mind for the replacement.

[Ooops]

I pulled the suspension relay and put a photo up of the diagram. The only continuity is between terminals 1 & 2. I pulled a second identical one and the readings were the same so I assume its functional. I'll check the others in the morning. In the mean time I've left the EAS relay out.

I also pulled out the USB hub, its too late in the day to see if its made a difference, I'll check tomorrow.

[Blknight.aus]

Does it require specialist equipment or is there a DIY method for load testing the batteries?

I'll pull the relay tomorrow and check it as desscribed

I'm not that happy with the USB mod so it'll come out. I'll keep your of fitting a switch in mind for the replacement.

Yes but its nor particualary accurate and reads a lot of false positives.

Put a known heavy load on the battery (all of your lights for 2 minutes) and read the voltage while the load is on, let the battery settle for 5 and check the voltage again.

repeat the check after a week of sitting if the voltage has changed significantly its self discharging.

of course a really bad battery will drop voltage in the 1/1000th and 1/100th range while you watch it with no load save the multimeter.