Thread: solar battery maintenance

Originally Posted by Blknight.aus

For the stay and live on solar deal you need ...... nearer to 4 times.

I've since seen five times recommended!

Originally Posted by Blknight.aus

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

Originally Posted by Blknight.aus

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

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.

Originally Posted by Blknight.aus

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?

Originally Posted by Blknight.aus

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

Originally Posted by Blknight.aus

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?

Originally Posted by Aaron IIA

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
The possibility of exceeding 24volts hadn't occurred to me

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

Aaron.

Originally Posted by Magnet6x6

I've since seen five times recommended!

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.

Originally Posted by Magnet6x6

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

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.

Originally Posted by Magnet6x6

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.

Originally Posted by Magnet6x6

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.

Originally Posted by Magnet6x6

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.

Originally Posted by Magnet6x6

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)

Originally Posted by Magnet6x6

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.

Originally Posted by Magnet6x6

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.

Originally Posted by Blknight.aus

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

Originally Posted by Blknight.aus

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

Originally Posted by Blknight.aus

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

Actually I think your earlier comment might be the answer

Originally Posted by Blknight.aus

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

Originally Posted by Blknight.aus

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.

yep I've had that happen recently

Originally Posted by Blknight.aus

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

Originally Posted by Blknight.aus

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

Originally Posted by Blknight.aus

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

Originally Posted by Magnet6x6

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.

Originally Posted by Magnet6x6

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

Originally Posted by Magnet6x6

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

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.

Originally Posted by Magnet6x6

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


yep I've had that happen recently





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.

Originally Posted by Magnet6x6

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.

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.

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