Dual battery system or Solar panel

[Koen]

Hi there!

I would like to have a second battery to run my fridge, some light and charge some stuff.
I doubt if I would take either a dual battery system or Solar panels.

With the dual battery system I want to put the battery under the bonnet, I dont have enough room to fit a big one, so that will be a Yellow top D34 with 55aH.

If I put in Solar panels I can fit my battery in the back, witch alows me to use a bigger battery up to 120aH.

So my question is, is the 55ah enough to run the fridge 24/7 and from time to time a light and some charging. Or do I have to go for a bigger battery witch forces me to go in the boot with the battery, then I would prefer Solar panels to avoid the hard wiring.


Thanks in advance,
Grtz, Koen

[Koen]

Other suggestions also welcome! ;)

[loanrangie]

What vehicle are you fitting this too ? The solar panel on its own will be useless without a storage facility (battery) so they go hand in hand.
Vehicle mounted aux. battery will allow you to run a fridge and lights for 3-4 days (batt size dependent ) without needing a top up, add a solar panel and you can extend this almost indefinitely in the right conditions.

[Koen]

It's for a disco 2

[p38arover]

So my question is, is the 55ah enough to run the fridge 24/7 and from time to time a light and some charging.

No. I had a 120Ah AGM in my P38A and I needed the solar panels to keep it topped up when running the Engel 29 litre fridge and a few LED lights. In summer, the car interior would often ride well above 40 deg C so the Engel ran quite a bit.


Or do I have to go for a bigger battery witch forces me to go in the boot with the battery, then I would prefer Solar panels to avoid the hard wiring.

My second battery was in the back and connected to the starting battery via a Traxide SC40 dual battery system. See SC80 - 90 amps Standard Isolator | TRAXIDE - RV | Traxide - RV (http://www.traxide.com.au/isolators/sc80---90-amps-standard.html). The SC40 doesn't appear to be available any more.

I had an Anderson plug at the rear into which I plugged the solar panels.

[PhilipA]

If you fit a second battery on the firewall next to the turbo (TD5) you can fit an Optima blue top to use as the starting battery with rewiring and then a 130AH aux will fit in the original battery tray.

I have had this setup for over three years with no problems so far.

I also have a 120watt solar panel running through an MPPT controller.

The problem with solar and a small battery is that the sun don't always shine, sometimes for days and some moderate cloud drops the output from say 7 amps to less than 1.
Regards Philip A

[Xtreme]

If you fit a second battery on the firewall next to the turbo (TD5) you can fit an Optima blue top to use as the starting battery with rewiring and then a 130AH aux will fit in the original battery tray.

I have had this setup for over three years with no problems so far.

I also have a 120watt solar panel running through an MPPT controller.

The problem with solar and a small battery is that the sun don't always shine, sometimes for days and some moderate cloud drops the output from say 7 amps to less than 1.
Regards Philip A
Interestng solution

If I understand correctly, you used the Optima blue top mounted on the firewall as your starter battery - have you experienced any detrimental heat effects due to it being so close to the turbo or did you do something about heat shielding?

[drivesafe]

Hi Koen, another option is to mount an Optima on the firewall, and fit one of my isolators.

Because my isolators share the load over both batteries, you will have around 90Ah available to run your accessories, like your fridge and lights.

If you fit a 120Ah battery in the rear, as a 120Ah battery gives you 96Ah of usable capacity, you will only gain about 6Ah over my suggestion above, but you will loose space in your cargo area.

[PhilipA]

have you experienced any detrimental heat effects due to it being so close to the turbo or did you do something about heat shielding? __________________

No, I had a look at the Blue top recently and there is no leakage or swelling that I can see.
I have a heat shield made from stainless steel on the end next to the turbo and spaced from the battery. I have also covered the stainless shield with bright aluminium reflective tape. In addition I have a thermal blanket around the battery, and I have polished the inside and outside of the turbo heat shield.

I have a dual battery controller from ABR which cuts at 12.4 volts which I personally feel is safer than 12.0 volts like Drivesafe's In my application. This contributes a share from the starting battery but not as big as Drivesafe's does.

I do note that the CCA is apparently not the only reason that D2 Diesels have a big batteries. I note that even when the batteries are both at 12.7-8 the starting 760CCA Optima blue top battery will pull down through 12.4 to about 12.1 as the ECU goes through it's set up routine, and if the batteries are at 12.4 , then the voltage drops down into the 11s,presumably because of priming the capacitors in the ECU. This is before I turn to start. Having said that It always starts really well.

The voltage reading for the starting battery is taken from the behind dash fuse box so may not reflect the voltage at the battery, however the batteries do separate at 12.4 reading on the second battery , which is taken from near the battery, so it's not too far out.

This is another reason that I personally feel safer with a 12.4 cutoff than a 12.0 cutoff with a D2 diesel when using a relatively small but high CCA Optima starting battery.

This is all specific to my experience with a D2 diesel and should not be taken as comment regarding D3 D4 .
However it works for me.
Regards Philip A

[Fluids]

I've got an Optima D34 yellow in a tray next to the turbo, against the firewall. One of Traxides USI-160 isolators, and a D31 yellow in the tray for the cranking battery,

I work on this setup being capable of providing 60-70 A/Hrs of power when run down to 50% SOC ... gives me 2-2.5 days running a 47L ARB fridge, some LED lights, and charging phone/iPad.

I use a 120W folding solar setup to recharge/maintain charge, which is adequate unless I get maybe 3-4 days of little sunlight.

I chose not to put the aux' in the rear of the D2 as I didn't want to loose the space there. I try to get everything charged whilst driving, and run the fridge at -5deg. When I arrive at the destination, I raise the fridge back to 2deg ... and usually, it won't cycle on again until sometime the following morning ... depending on how often it's opened, and how the ambient temperatures running. This can give me an easy extra 1/2 day or more of run time before hitting 50% SOC.

I do the same with the Kamper ... While the engine is running and your travelling, pull the temp of all your fridges down, letting the alternator do all the hard work. I've has a few cases where, in lower ambient temps, we've pulled in around 3pm, I've raised the fridge back to 2deg, and it hasn't cycled back on again until around midday the following day (fridge in Kamper, not D2)

[Blknight.aus]

to run an engle for 24/3 with a couple of hours of led lights and and hour or so of laptop use you need an N50 and 80W worth of panels.

the battery doesnt have much left in terms of safe capacity at the end of day 3 but it would probably make out that night but you'd be hanging off the panel for the next day and might not make the evening of day 4

[drivesafe]

I have a dual battery controller from ABR which cuts at 12.4 volts which I personally feel is safer than 12.0 volts like Drivesafe's In my application. This contributes a share from the starting battery but not as big as Drivesafe's does.
Hi Phillip and because your cranking battery is most likely not going to be in as higher state of charge as what a cranking battery is going to be with one of my isolators in the system, you are not likely to get any useful assistance from your cranking battery.


The voltage reading for the starting battery is taken from the behind dash fuse box so may not reflect the voltage at the battery, however the batteries do separate at 12.4 reading on the second battery , which is taken from near the battery, so it's not too far out.

This is another reason that I personally feel safer with a 12.4 cutoff than a 12.0 cutoff with a D2 diesel when using a relatively small but high CCA Optima starting battery.
Phillip, your isolator works just like any other ordinary isolator.

While you may not understand the full operating implications of how my isolators work, and contrary to your thinking that they are not as safe as ordinary isolators. Quite the opposite is the case.

First off, with my setup, if the cranking battery is still low when you turn your motor off, the auxiliary battery will reverse charge back into the cranking battery, continually raising the cranking battery's state of charge.

Your isolator and all other isolators can not do that.

Next and another concern of yours is that my isolator does not separate the batteries when starting.

That is actually a major advantage and for a number of reasons.

Firstly, by keeping the batteries connected, you have a higher CCA available while cranking, than the cranking battery by itself, can provide. My isolators are specifically designed to keep the batteries connected for up to 10 seconds while you are starting the motor, even when the voltage drops bellow 12.0v

This means it is easier to start the motor but you are not working your cranking battery as hard while starting your motor.

It also means, because at least 10% of the energy needed to start your motor is coming from the auxiliary battery, once the motor is started, the cranking battery does not need as much energy to be replaced, and this means the cranking battery is going to be RECHARGED in a shorter driving time.

So with one of my isolators, not only do you have at least 50% more battery capacity available to run your accessories while the motor is off, without having to actually add additional battery capacity or the weight and space needed for that additional battery capacity, as you would have to do with your setup.

You are also charging and maintaining your cranking battery far better than any other dual battery system can.

Contrary to your concerns, my systems are literally win, win, win dual battery setups. And there are a lot more feature available with my system that are not available with any other DBS.

[Blknight.aus]

First off, Tim might be a little off the money depending on which ARB isolator you have, if its one of the all singing all dancing ones that features the letters dcdc or bcdc in the title then hes on the money, if you have one of the antique ones that is a solenoid driven unit then the system will still back charge but thats about as far as it goes.

I'm personally prepared to allow Tim a lot of leeway when it comes to how he advertises his product in comparison to others because
a, the capability he talks about from his product is on the money,
b, there are a lot of older competing systems, obsolete systems and odd ball configurations its a little unfair to expect him to compare all of those systems in one go to his products and
c, for the info he gets "wrong" about the systems hes comparing to in probably more than 50% of the cases their capability claims are even further from the truth.




when you read what Tim just wrote about the capacities of the batteries in his system it can sound like smoke and mirrors, and it sort of is right up until you know how its done. Mr Peukerts has the spoilers in wiki.

[drivesafe]

Hi Dave, and thanks for the buildup and I agree with your comments about "ARB" gear.

But Phillip has an ABR isolator, not an ARB.

The use of the letters, ABR was done deliberately to cash in on the well known brand name of ARB.

[Blknight.aus]

just checked em out...

huh, just exactly like the vintage ARB one...

[PhilipA]

First off, with my setup, if the cranking battery is still low when you turn your motor off, the auxiliary battery will reverse charge back into the cranking battery, continually raising the cranking battery's state of charge.

My batteries stay linked down to 12.4 volts so the second battery does charge the starting battery. I have never seen the starting battery low on shutting down and imho it is not possible on a D2 under normal circumstances.

You are putting words in my mouth. The only point I was trying to make talking about the batteries separating on starting was to observe what looks like a quirk of the D2 ie a very heavy load on ign on, which means that if the battery is at 12 volts then the voltage drop could be a problem. I don't really see how linking a flat battery , which the house battery is likely to be, to the starting battery while starting helps anything.

I have the ability to link the batteries if necessary with a dash switch but I have never had a situation where the second battery is higher than the starting battery.
As I said it works for me.
Regards Philip A

[drivesafe]

Hi again Phillip and I was not putting words in your mouth, I was simply correcting the false information you had been fed.

If you measure your two batteries after a few days of not running the motor, you will find your cranking battery and auxiliary battery will be at different voltage levels and they will be bellow 12.4v.

Your system DOES NOT share the load because the 12.4v setting is far to high to allow the batteries to equalise before the cut-out level is reached, unless one or both were charge with a battery charge.

Further more, even when driving, if you do a couple of short drives, when you turn off your motor, your cranking battery will quickly settle bellow 12.4v and even if your auxiliary battery is in a higher state of charge, because you have to have that isolator mounted close to the cranking battery, as the cranking battery is in a lower state of charge than the isolator's cut-out voltage level, the cranking battery will pull the voltage down at the isolator, causing it to turn off.

So once again, you will not get any benefit from that isolator, and the info you have been supplied about it is nothing but false advertising.

Even when you first turn your motor off, there will be a surface charge on the batteries, but put a small load on them, like a fridge, and within a short period of time after applying the load, your isolator will turn off.

From many years of research and development, I have found that any cut-out setting much above 12.2v offers no real benefit, because the cranking batteries can easily settle down to 12.2 or 12.3v in normal use with just a small load like a fridge running and those levels will negate the sharing of energy with the auxiliary battery.

[PhilipA]

Look I don't want to get into yet another of these never ending threads where you aggressively defend your system and call into doubt the quality and or intelligence of anyone else.

Suffice to say that NONE of the things that you claim apply to my experience.

I keep an eye on my batteries and I keep them both above 12.5 to reduce sulphation. If the batteries go below 12.5 I charge them and I have an LED readout on the dash to monitor them. My batteries always stay connected for several days at the least and in practice are connected most of the time.

I use the system I do from long experience with what works for me not from what anyone tells me or claims. I have had dual battery systems since 1990, and have designed and run a 2 alternator system in my RRC successfully with separate circuits for starting and house. .

It may well be that your system works well but mine also works well.

My reluctance to use your system is

1 12 volts is <= 50% SOC, and the draw from ancilliaries like opening doors etc could reduce this further over a few days, after the batteries have separated. My fear on a D2 is that this could become marginal for starting as the ECU cuts off at AFAIK about 11.5 volts and the house battery will probably be that low anyway.. As one is "up the creek without a paddle with an auto with a flat battery" I prefer to be conservative.
Regards Philip A

[drivesafe]

Hold your horses Phillip. You make unsubstantiated claims about my products, based on nothing more than your ignorance.

You had no real idea how either system works and you specifically stated that your concerns about my system were based on nothing more than your opinion.

Then, when I explained how both your system and my system worked, you accuse me of "putting words in your mouth"

I am not sure what you based your decision on when you bought that brand of isolator you have, and while you seem only to happy to make unsubstantiated claims about my products, yet you have bought the most unreliable isolator on the market and if you care to do a bit of research, you will find plenty of posts, on many many forums, about how much trouble it is to get the warranty honoured when the fail.

You have a nice day Phillip.

[drivesafe]

My reluctance to use your system is

1 12 volts is <= 50% SOC, and the draw from ancilliaries like opening doors etc could reduce this further over a few days, after the batteries have separated. My fear on a D2 is that this could become marginal for starting as the ECU cuts off at AFAIK about 11.5 volts and the house battery will probably be that low anyway.. As one is "up the creek without a paddle with an auto with a flat battery" I prefer to be conservative.
Regards Philip A

And a little more info for you.

You make out there is a risk of once my system has discharged the battery down to 12.0v, then if the doors are continually opened, the cranking battery is going to be discharged down to low to start the motor.

Well you are correct, that can happen, but the problem for your claim is that it also happens to people who have an ordinary isolator, like yours, or no no dual battery system at all.

Further it is less likely to happen, but still can, when someone has one of my isolators fitted.

And this is because my isolators work in both directions, so while the isolator is still cut-in, the load caused by opening doors is shared of both batteries so the cranking battery will be able to take much use before the battery is so low that it becomes a problem.

[PhilipA]

Drivesafe, I looked back at my posts and I cannot see that I have made any statements about your product other than it cuts off at 12 volts, which I think you agree with.
I cannot see how this constitutes an "unsubstantiated claim based on nothing more than your ignorance." You have noted several features of your product that are not directly related to that simple fact.

I have found that personal attacks are unhelpful and in fact I went to lengths to mollify you by saying that my setup is based on my personal experience.
I have tried to help a fellow forum member who had a question on how to approach a dual battery installation on a D2 diesel, without seeking to denigrate your product, however your product is only one of literally hundreds of solutions in the market .

With that I will vacate the space . I have set out my system, and my experience with it .
Regards Philip A

[drivesafe]

I have a dual battery controller from ABR which cuts at 12.4 volts which I personally feel is safer than 12.0 volts like Drivesafe's In my application.
I have already covered why my isolators would NOT be dangerous in your application, as you implied.

[Keithy P38]

I'll put my 0.02 in (no fire added!).

My previous P38 ran an SC80 and I'll back that thing until the cows come home. My reasons are many and varied, but one that applies to most campers on this forum is the back-feed. I'd guess many here would have some sort of solar running to the aux battery, which I do, and in my case it worked two-fold by also charging the crank battery as well. Never an issue starting the (auto only) P38 after a week at camp.

My current P38 - decked out very well. Has a BCDC charger (redarc). Aux battery is unable to sustain running a smaller fridge than I used with previous P38 unless I have the solar plugged in. Case in point was just yesterday - parked at camp at midday, thought id leave the solar off until the next morning. My battery was dead flat by nightfall. On my SC80 setup on a summers day with my bigger fridge I'd get until midday the next day before I desperately needed the panels.

Cheers
Keithy

[Keithy P38]

I should add to the above, the reason the SC80 setup was better then the BCDC setup is

A) The SC80 charged from the alternator and current to aux battery was much higher. BCDC chargers don't give high current charge to your battery in short drives (even though the battery was on a 240v Ctek charger before I left and the fridge was pre-chilled).

B) The extra AH capacity provided by the lower cutout voltage on the SC80 was enough to run the fridge overnight and half of the next day, once the solar is hooked up it maintains both batteries (provided they are still linked - easily sorted by starting the engine for a minute if they are not linked).

Cheers
Keithy

[DiscoMick]

I should add to the above, the reason the SC80 setup was better then the BCDC setup is

A) The SC80 charged from the alternator and current to aux battery was much higher. BCDC chargers don't give high current charge to your battery in short drives (even though the battery was on a 240v Ctek charger before I left and the fridge was pre-chilled).

B) The extra AH capacity provided by the lower cutout voltage on the SC80 was enough to run the fridge overnight and half of the next day, once the solar is hooked up it maintains both batteries (provided they are still linked - easily sorted by starting the engine for a minute if they are not linked).

Cheers
Keithy
I think most DC-DC chargers operate at between 20 and 30 Amps, for example the Matson one I have in our camper operates at 20 Amps. However, a Traxide unit with the correct wiring can carry much more than that. My set up has heavy wiring with 60 Amp fuses at both ends, for example, but I've heard of people going higher than that.
So, more power equals faster charging.

[kelvo]

I've managed to fit an 80Ah battery next to the turbo on a bulkhead mounted tray. Isolated using a Traxide USI-160. Been there since 2014 and so far no problems.

[simonmelb]

Which 80Ah battery fits there ?

[kelvo]

Which 80Ah battery fits there ?

This one Super Start Batteries > Products > Product List (http://www.superstart.com.au/Products/ProductList/tabid/108/mode/details/pid/720/Default). it is actually marked as 80Ah on the battery.

Had to trim the under bonnet ribbing slightly, but the black sound proofing can stay in place. I'll get photos later.

EDIT Photos added.

http://www.aulro.com/afvb/attachment.php?attachmentid=105827&stc=1&d=1455713542

http://www.aulro.com/afvb/attachment.php?attachmentid=105828&stc=1&d=1455713542

[Blknight.aus]

1 12 volts is <= 50% SOC, and the draw from ancilliaries like opening doors etc could reduce this further over a few days, after the batteries have separated. My fear on a D2 is that this could become marginal for starting as the ECU cuts off at AFAIK about 11.5 volts and the house battery will probably be that low anyway.. As one is "up the creek without a paddle with an auto with a flat battery" I prefer to be conservative.
Regards Philip A

FWIW IME.

if you have more than 10.5v the ECU will let you attempt a start, so long as the voltage stays over 8.5 it will keep trying, below 10.5V it shouldn't attempt to have a go however some will. Trying to start with under 11.5v showing prior to the attempt and you are going to get error codes, more with the auto but they should all be soft faults and should go away after 5 start events without the fault logging.

[rrturboD]

Koen,

My thoughts: If you are chasing AH, put the starting battery on the firewall (D34 or D34M) This will cost you a battery lead from existing battery location to the new battery.
Put a larger AGM deep cycle battery in place of the original starting battery.
Use a Traxide SC80 or 160 controller. You can always add a portable solar kit in the future.

My son is currently contemplating this setup with his D2.

Michael T
Disclaimer: I sell batteries!