24volt Solar Panel to 12volt Van Battery

Thanks for your feed back guys. Much appreciated :)

So did you sort it the hard way then !Shouldn't have taken four months to move the strap even allowing for a couple of minutes to remove and replace the cover lol !Of course you may have a 24 volt only panel - I've not seen any yet but they quite possibly exist .

yes they do -CMPV solar have a 24 voltonly optionwe have been using a large number of these on our high telecommunications sites for a few years now

Another simple method, use the 24 solar and add another 12 v battery to make a 24 v bank, then run the items off a 24 to 12v reducer. Works in our home ( which is a boat) .

Any one able to shed some light on how I can succeed in this!

Is it possible to recharge a 12 volt battery from a 24 volt solar panel!
What extra err 'things' would one need and what sort of wiring configuration is best!

It's for a spare battery to run small things in my van, such as phone / laptop power and a small car fridge on the odd occasion etc.

you need a regulator to charge the battery. you can get them from just about any motor home place. or you could try googling. rvworldstore

Are you sure it doesn't have alternative ways to strap it in the connection box on the back !I'm using some that can be strapped for 12 or 24 volt battery charging. The 12 volt strapping choice is about 20 volts on open circuit and the 24 volt about 40 v.

Yup what solar says.
If you just regulate it you will only be getting half the current you should be able to get if you reconfigure it in the box at the back of the panel.

Is that because the battery would only draw a small current from the solar panel!

Any one able to shed some light on how I can succeed in this!

Is it possible to recharge a 12 volt battery from a 24 volt solar panel!
What extra err 'things' would one need and what sort of wiring configuration is best!

It's for a spare battery to run small things in my van, such as phone / laptop power and a small car fridge on the odd occasion etc.

Are you sure it doesn't have alternative ways to strap it in the connection box on the back !I'm using some that can be strapped for 12 or 24 volt battery charging. The 12 volt strapping choice is about 20 volts on open circuit and the 24 volt about 40 v.

It's because the panel can only produce it's rated output in watts. Ohms Law says Watts = Volts times Amps so if your panel is strapped to charge a 24 volt battery (like 2 12v in series ) you'll only get half the Amps you'd get using the 12 volt strapping. Halve the voltage, double the amps - the watts stay the same.

Mate if you have a 12 volt battery to start the van and another 12 volt battery to run the accessories, here is how you could do it. Run the + from the solar unit to + on the start battery. Connect - on the start battery, (Through a Diode) to + on the accessory battery, and then the - from the solar panel to - on the acc battery. Doing it this way makes the batterys in series and therefore 24 volt, so can be charged with 24 volt.The Diode prevents the Link between the batterys from going back to a common ground, which could cause a fault. It is also recomended that you use a solar regulater, as it is possible to discharge the batterys on a dull day, through the solar panel.

dodgy The acc batt connected to earth starting batt connected to earth and a diode between. short circuit much

And if you do put relays or some other trickery in there to prevent a short, the two batteries will need different amounts of charge, so one will be over charged or the other will be under charged.

Crazy plan.

Better listen to Solar or Matt. or me. We know what we are talking about.

Well said. Good post !

It's because the panel can only produce it's rated output in watts. Ohms Law says Watts = Volts times Amps so if your panel is strapped to charge a 24 volt battery (like 2 12v in series ) you'll only get half the Amps you'd get using the 12 volt strapping. Halve the voltage, double the amps - the watts stay the same.

Maybe I would suggest then instead of the diode protection, that a battery equaliser circuit be used,,, or,,,
, use a couple of 12-volt batteries in series as a 24-voltbattery. Charge this in parallel with the starter battery via an isolating relay and, if solar is used, use two series-connected 12-volt solar modules to supply 24-volts via a 24-volt solar regulator.

All I can say is WTF!

Just run another 12v battery then you are using your panel efficiently and ALWAYS keep starting batt separate from house system:)

I see that poster 1 hasn't been back but I still strongly suspect that he just needs to move a strap (a very short wire with probably spade terminals on the ends ) and problem solved, he then has a 12 volt panel . Feedback is always appreciatedO P.

It seems like I am always right in the end.

http://www.caravanandmotorhomebooks.com/articles/12volt-24volt.htm

Er, actually, you're not.
Matt is an auto electrician, I'm a mechanic that is good with electrics and I live with solar power, and solar boy knows what he is talking about whatever his background is. I think you shuld give up trying to prove us wrong.

Solarboy has the answer. They need to reconfigure their solar panel.

24volt Solar Panel to 12volt Van Battery - HOW TO!

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