Leisure battery discharging whilst driving

[Gooners on Tour]

I am currently in Bulgaria on the way back from Greece. I have a 200ah KS Energy lithium leisure battery that is discharging at 15-18 amps/hr whilst driving. If I turn the fridge off the discharge stops and then I see a few amps charging via Solar. The battery charges fine when Solar or EHU. I can see all this via the KS energy app.
The engine battery is charging fine, I have checked this with a multimeter. I have found a number of fuses in the vicinity of the leisure and engine batteries and also the B2B charger - all are fine. I have checked all battery connections and continuity between the batteries - again all fine.
The B2B has some LED’s which illuminate so there is power to it but after my basic fault finding I am beginning to suspect the B2B maybe faulty?
I would appreciate some technical input and/or some further checks I can try from some Funsters who have far greater knowledge on this subject than me!

Thanking you in advance.

 

[Gooners on Tour]

Thanks for all the replies and helpful advice guys, it’s much appreciated. I think we’ve gone as far as we can for now, I’ll just turn the fridge off whilst driving and hopefully get the B2B replaced under warranty (2 months left!) when I get home.

 

[AdrianChen]

Think the 0.4a charging is from Solar, very overcast here!
I’ve checked all fuses and connections.
Unable to change any settings in KS app, it’s info only. Also cells are all balanced.

Mmm, then possibly no output at all from the b2b?

I take it that it is the original install when the van was built - if it were retro fit I would be suspicious of there being a Split Charge Relay that hadn't been disabled, which would neutralise the B2B, but if it's always been there then I'm beginning to think it should be removed and tested.

Sorry I've not been able to help.

 

[Gooners on Tour]

Mmm, then possibly no output at all from the b2b?

I take it that it is the original install when the van was built - if it were retro fit I would be suspicious of there being a Split Charge Relay that hadn't been disabled, which would neutralise the B2B, but if it's always been there then I'm beginning to think it should be removed and tested.

Sorry I've not been able to help.

Original install so should get sorted under warranty.
You have been a massive help - Thank you.
I’ll update this thread if and when it’s sorted!

 

[Gooners on Tour]

Update as promised. Supplying dealer has tested the DC-DC charger and confirmed it is not putting out a charge. They have ordered a warranty replacement. Thanks again for the help and advice .