I have a boat with a service bank and an engine battery.
I have a Multiplus charging the service bank and the engine battery with the aux output. Now i have the multiplus switched off as i'm off grid and a solar array charging the service bank.
What i noticed is that some current is flowing also to the engine battery (and the only common point as everything else is disconnected is the multiplus and the aux battery reading of a smart shunt).
Is it possible that some current is leaking up to the multiplus cc input/output to the aux output and to the engine battery?