Club 80-90 Forums

Im trying to solve a problem but have got stuck, i have a leisure battery and a mains feed into the van the mains is converted to 12v to power all 12v items in the van and i use a switch to change between battery or mains. The problem is i want the battery to charge when im running off mains, but how do i set that up so when i plug in the mains it doesn't charge the battery till i have changed to the mains feed. Otherwise i would be charging and running off it at the same time.

Firstly, welcome to club 80-90 (where you can find everything you need to know, and lots that you don't )

jkaufman94 wrote:I have a leisure battery and a mains feed into the van. The mains is converted to 12v to power all 12v items in the van. I use a switch to change between battery or mains.

OK, this is pretty normal, but, you need to find out how the 240 Volt mains input is being converted to 12 Volts. If it is being done by the use of a battery charger, as is very often the case, then you are in luck. Please have a hunt around and let "us" know what you find in the way of a step down to 12 Volt unit.

jkaufman94 wrote:The problem is, I want the battery to charge when I am running off mains, but how do I set that up so that when I plug in the mains, it doesn't charge the battery till I have changed to the mains feed. Otherwise I would be charging and running off it at the same time.

That is not a problem, read on.... I bet you will find a battery charger in there somewhere. If you do, you need to let us have some details as to what it looks like and what is written on it.

Chances are that as soon as you hook up to the mains, the charger will come to life and set about charging your leisure battery. You can happily run any of your 12 Volt leisure equipment (except using the fridge on it's 12v setting) at the same time as charging it. No problem.

The only thing to check (and I am repeating myself here, I know) is the "spec" of the "unit" that is providing the 12 Volts from the mains input. The reason for the check is that most modern chargers are "intelligent" and will automatically drop their charge rate to a trickle once the battery is charged up. Earlier primitive chargers don't do this, and might possibly overcharge your battery if left on for too long.

Do you own any sort of multimeter ? If not, get yourself one. A £10 one from the likes of Maplin will be fine for what most folk need for testing van charging etc.

Thanks for the welcome.

At the moment the 240v input is being converted to 12v via a transformer with a switch to change between the battery and the transformer, so do you think it would be best to simply change that out for a battery charger and then power everything off the battery (apart from 240v appliances)

Also could you suggest a good battery charger for this, the battery is a 115ah with a split charge relay

Thank you very much

jkaufman94 wrote: At the moment the 240v input is being converted to 12v via a transformer with a switch to change between the battery and the transformer, so do you think it would be best to simply change that out for a battery charger and then power everything off the battery (apart from 240v appliances)

Yes, if it just a simple transformer (and a rectifier of course to make it DC ) then replacing it with a modern (say 10 Amp) intelligent battery charger would be a good idea. From what I have read on here, a lot of folk recommend "C-Tech" brand (I might have the spelling wrong there). There are lots of others though Suggest do a search on here for "battery chargers" and you should find lots of info. Also try looking in our "wiki" knowledge base, available from any page on here, look for the "wiki" link near the top left of the page. (but don't worry about asking questions, it's one of the reasons we are here )

Something like: hard wired (fixed permanently)

http://www.ebay.co.uk/itm/Numax-12V-10A ... 4ac6648e04" onclick="window.open(this.href);return false;

Martin