Campervan draining engine battery when on EHU?

[Felix]

That lot looks a tad over complicated. A simple 140A Durite split charge really can be had for under 20 quid. Replace that over priced Sterling Power Keek and see how it goes. Cant see why its needing a large solar isolator.

Any chance your sis it sitting in the van listening to the van radio. Add that to opening doors who may turn a light one and some step lights. If she is using a full awning the doors could be open all day. Has she a diesel heater? Is it wired to start or leisure battery? Ask her how many amps the start battery is if she is using it in error it wont last long. Main mistake is a USB socket in the dash power socket and phones attached. Not all van/car power sockets turn of with the ignition.

[Taipan]

It's set up as an off grid camper, with everything from 3 solar panels and 2 inverters and even a composting toilet. When parked up they dont even use the cab area it's still behind the bulkhead. The camper part of the van is completely separate to the cab area and the only way to access the camper part is through the side door.

It's never had a problem set up like this before. Most of the time they are off grid, but if they've met us on a site they plug in to ehu as they're paying for it, but the van has always started until they went to the festival. They left the festival after 2 (or 3) nights and it wouldn't start as the battery was barely putting on the ignition lights. But its not on ehu now and its been left for well over a week and fires straight up as normal. Something happens to drain the main battery when the ehu lead is plugged in?

[Mr. Dazzle]

It sounds like it is set up so that when you're in EHU the system isolates the vehicle electrics from the leisure electrics. This is a pretty sensible idea TBF cause you don't run the risk of firing 240V AC into a system built for 12V DC.

You can get "invertors"* which can convert that 240V AC back to 12V DC and charge the vehicle battery from the EHU, but maybe your sis doesn't have one of those.

When she's on solar, which outputs low voltage DC, you don't have to worry about frying the car with 240V AC so you can let the leisure system charge the car battery.

When they visited you and used EHU how long was it for? Could just be the case that plugging into EHU has always isolated the vehicle battery but its just never been long enough to notice. Perhaps over 3 days some minor draw flattens the car battery and she's just not ever done that before?

*The word Invertor is doing a lot of work in all these posts. . Invertors convert DC to AC and nothing more. They're often partnered with transformers, rectifiers and regulators etc. to achieve all kinds of other things like converting voltages and switching things around. Doesn't really matter, we could just say "magic black box of electricity".

[Taipan]

We've been away with them for normally 2 nights, but they've stayed on for the 3rd night on EHU before with no starting problems. She's just told me it happened once before when they was away for 2 nights on electric hook up and it turned over but didnt catch. Fortunately she got a jump start. They assumed they'd left something on. The next time they used it was for 3 nights at the festival and the battery barely had enough juice to light the dash lights with the ignition on. So it does seem like a fault that has only recently developed and only when on EHU?

I'm off wandering round the west country in my own camper ina coupel of days time, so wont get the chance to look at it before then. Which is a shame as I'd like to have got some better pictures of what wires are going where. My Sister is not technically minded at all and nor is her other half, so I do need to check they haven't inadvertently switched something over etc.

[Mussels]

My car has two batteries and split charging for the stop/start system. Recently I had the alternator fail and the car died ten minutes later even though the battery tested ok. I still have no idea what really happened as I replaced both but it might not be because of the leisure system.

[Taipan]

My car has two batteries and split charging for the stop/start system. Recently I had the alternator fail and the car died ten minutes later even though the battery tested ok. I still have no idea what really happened as I replaced both but it might not be because of the leisure system.

The charging system and battery was given the all clear, but i'll stick a meter on it when I get over there to check.

[Yorick]

Stick a meter on the vehicle battery. Then test again with EHU.

[gremlin]

What you have is a gremlin. No known cure except to destroy it by fire.

We can burn @gremlin ?

Cool

You'd miss me too much.