motorhome battery charging

[motorbiking]

I have a motorhome which has a leisure battery charged off the mains (or the engine when running) and van battery used to power the engine. Its alarmed, so the van battery needs to be topped up regularly when not in use. I have the leisure battery on a timer via mains, so that gets topped up, but due to complexity of modern chargers, can't automatically top up the van via the timer, since the charger has to be manually set each time.

The motorhome has 12v cigarette sockets as well as the van/cab. If I rig up a 12v to 12v male to male Cigarette plug, and run it between the two sockets, will the leisure battery (topped up by mains) keep the van battery topped up too?

e.g. something like this https://www.ebay.co.uk/itm/12v-Car-...dc-power-lead-cable-1m-10m-3-25A/272454685622

The load on the van is just the alarm, so I'm assuming a 3A cable would be fine?

 

[alan333]

Can't say for certain, but it sounds like it would work... but only if the van cig lighter is live when the ignition is switched off.

 

[motorbiking]

Thanks - I think I'm scuppered then, I may have to go 12v socket to crocodile clip, direct to battery instead.

 

[alan333]

Would it be worth wiring a trickle charger to the van (or both, for that matter) circuits? No need for timers with my motorcycle one.

 

[motorbiking]

I don't really want power flowing 24/7, so I have the hookup cable on a timer switch. The problem I have with chargers is they all seem to need to be manually set. Plus the consumer unit in the van already has 12v charging circuit built in.

mind you this seems to be automatic:
https://www.toolstation.com/shop/p17423