charging leisure battery from campsite hook up?

[somaRich]

Is there anyway to charge the batteries from the camp site hook up? I currently just have a 3 way gang for running a heater and chargers but would like to charge the batteries to. Is this possible?

[Dodgey]

The simplest way is to buy a regular mains battery charger, and plug it into your 3 way socket. Then connect the charger to your battery

[somaRich]

Hi Dodgey, I was thinking that. Will have a look for mains chargers.

This one looks good, would you connect it to main car batter, or the leisure battery?
http://www.amazon.co.uk/AA-Essentials-5 ... ery+Charge

[Dodgey]

Well, it depends which one you want to charge

no - seriously - I'd connect it to my leisure battery. After all, that's the one you are going to be using when camping. Your SB should not be being drained.

If you have a voltage sensing relay split charging system then you could connect it to the SB, which will then trigger the VSR and link the SB to the LB, thus charging both batteries.

[somaRich]

You lost me a bit there!

I think I must have some connection between my main battery and my leisure battery as the alternator charges both. I was a little worried about having all the interior lights on as I bet these are connected to the main battery not the leisure battery.

So if I install this AA charger to my main battery how will I know its charging my leisure battery to?

[Dodgey]

Ok - 1st you need to know what parts of your electrics are plugged into which battery.

Switch on the thing you are testing, for example, your interior lights, or your radio, or your 12v cigar sockets, then go under the bonnet and disconnect the earth from the LB (leisure battery) - if any of the things you are testing turn themselves off, then you know they are connected to the LB. If not, then they are connected to the SB (starter battery).

Regarding the fact your LB gets charged by your alternator, you have one of 3 things.

1- Your LB and SB are connected permanently - not great
2- You have a split charging relay system - this links the two batteries only when the engine is running. The old system uses a wire from the alternator to trigger the relay (that makes the link).
3- You have a split charging voltage sensing relay system (VSR) - this is the same as above but no wire from the alternator is needed. It is triggered when it senses the voltage in the SB increasing. When you start the engine, the alternator pumps current into the SB, the SB voltage climbs, this climb in voltage triggers the voltage sensing relay that then links the 2 batteries, thus charging them both.

If you plug your mains charger into the SB, and IF you have a VSR system fitted, the climb in voltage will trigger the split charging VSR relay just as it would if you had started the engine. This means your mains charger will then charge both batteries.

[somaRich]

Thanks Dodgey! I will go and do some testing!

[somaRich]

I went and had a look, this is what connects the two batteries, so I think I can connect my charger to the SB and this will then charge the LB?

[g8dhe]

You have quite an old system there which uses Diodes to separate the two batteries, the problem is each diode drops 0.6volts so the batteries are never charged to capacity Its why newer systems use Voltage Sensitive relays this don't cause such a voltage drop.
Connecting the Charger to the SB will NOT charge the L?B nor the other way around either, the charger would need its own pairs of diodes as it best NOT connected to the Alternator input either.

[Dodgey]

Aye - what Geoff says. You don't have a VSR so just connect your charger to your LB.