I have had in the past the same problem. The explanation I was given was that the internal workings on the van and its diagnostics constantly uses battery power albeit small but nevertheless will put a constant drain on the van. I even have a power switch by the door if I switch this off it still drains the battery and was told that is resistance. So in the end after ruining a leisure battery by letting it go flat i take the battery out of the van and charge it once a month/3 weeks. If you take out the battery dont store it on a cold concrete floor as battery doesn't like it and helps with its demise.
One tip I have for you is as you may want to remove the battery on a regular basis is to remove the bolt on terminals and replace with quick release clamps I think they cost about a fiver.
------------- A barman is just a pharmacist
with a limited inventory
Hi
Look out for the smart chargers in Lidl and Aldi, they are brill and cost about £12.99/£14.99, many swear by them as I do now that I've used them both. I've just revived an ordinary car battery from dead flat (stood flat for 10 months) to fully charged and stable again, that's worth the cost of the above 4 times over.
Best of luck with your problem and hopefully, with the right treatment, you'll be caravanning again next year with the same battery.
we take our battery home each winter and keep it in front lobby, i charge it 2-3 times over the winter checking the battery at first charge to see if it needs cells topping up and had no bother.
------------- Live Each Day Like Its Your Last, One Day Youll Be Right
When I bought my caravan it had been stood for 2 years (possibly more). I thought "the battery won't be any good".
When I went to pick it up, the bloke said to me "I suppose you'll be wanting the battery?"
He went out to his shed & promptly produced a very old looking leisure battery. He said to me "I've been charging it every 2 months, so it might be alright".
I've not only tested it but used it, it's fine. Holds a full charge for weeks. In fact, I haven't taken it out of the van as I planned to use it again in a few weeks. Went out today to take one of the taps apart (another issue entirely) & it was still showing full charge.
I haven't fitted my 12s plug to my car yet, so am opting for EHU at my next camp (New Years), but after that I will be mostly giving up on EHU & letting the car & the "unicharger" unit (fitted by previous owner, at great expense) do the work instead. (A lot of my trips there is no EHU available anyway, & apart from the fridge & battery charger, I've got no other mains equipment on board).
My motor mover and radio/cd player would flatten my battery within a couple of weeks if I didn't have the caravan plugged in on the driveway. The motor mover radio receiver is permanently active, although power is only sent to the motors once a signal from the handset is received. The radio has a permanent power supply for the station memory pre-sets.