# Can I charge my battery and power 12v circuits?



## Towbaron (Jul 8, 2011)

Hi,

I’m in the middle of a camper van conversion and I’m planning on fitting a leisure battery to power a 12v fridge and lights etc. Charging the battery with a split charge relay arrangement and when available via a 240v hook-up and battery charger. 

From my investigations so far it appears as if the preferred type of charger (3 or 4 stage type) for 240v hook-up should be dedicated to charge the battery only and not power the 12v appliances at the same time. It seems that the output voltage of these chargers is greater than 13.6v, the highest voltage that most 12v appliances will tolerate without blowing up.

My question is: When parked up and plugged into a 240v hook-up, is there a charger/charger system which will happily charge the leisure battery and still allow the 12v appliances to work at the same time?

Cheers

Towbaron


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## clive1821 (Mar 27, 2010)

Yes mostly all mains chargers will charge the batterys and as you have the 12volts from the leasure batteries powering the lights etc theres no reason to worry.... a 20 to 25amp charger will do.... hope that helps a little  best of luck with your build...

ps it will not matter about the volts going upto about 14 volts its quite normal and all 12volt electric will be fine


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## Losos (Oct 28, 2009)

Basically agree with Clive.

I assume you are using a 3 way fridge because SFAIK when on 12 volt most fridges only 'hold' an internal temperature, they will not 'lower' it, you need to have it running on gas to do that. It follows that each time you open the door when on 12 volt some cold air is lost and the internal temp. rises slightly.

I use a Sterling Combi unit, this charges the leisure battery when on EHU and when no EHU is available provides 240v ac.

Sterling also do a range of battery charger *only* units of all sizes and I can recommend them, in fact I would go so far as to say they are *one of only a few firms who really understand what a motorhome really needs in the way of electrical kit.*

http://www.sterling-power.com/


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## Towbaron (Jul 8, 2011)

Many thanks – that’s a relief. It would be a bit irritating if one had to wait for the battery to charge up before putting the lights on!!

It’s a micro camper conversion with limited space; the main electrical consumer will be a small 12v or 240v (with inverter) fridge at about 50W. If my calculations are correct it should draw no more than about 4 amps. 

Next question: If we put in a 100 Ah leisure battery what size of charger would be adequate to charge the battery and also power the fridge?

Many thanks

Towbaron


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## Towbaron (Jul 8, 2011)

*Ditch the fridge for a cool box?*

The fridge seems to be the main drain on the electrics - after all it's only there to keep a couple of pints of milk, a lump of cheese and few cans cool - but can cost hundreds.

Ours is only a micro camper and probably we will be away in it for the odd week at a time. A state of the art fridge may do the job and consume the least electricity but it's really a bit on the extravagant side.

I quite like the idea of a well insulated cool box; starting out with plenty of frozen milk and cans to keep everything cool for a few days and if there's a convenient hook up available plug in the Peltier cooler device to see us to the end of the trip.

Anyone done something similar?

Cheers

towbaron


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## TR5 (Jun 6, 2007)

If your going the coolbox route, why not buy one that also runs on camping gaz?

When the weather's dry, you can site it outside and use gas to power it, and keep your beers cold.

That way, when your not looking, we can help ourselves to a nice cold beer!


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