Originally Posted by Ned5555
I have an email into SMB Texas asking if the battery separator should have prevented this. The house batteries were charged every few weeks, always staying at 80-90% SOC. My understanding was the separator will kick in extra juice if the engine battery is struggling. Anyone know if the 12V master house power needed to be on or off for this to work?
Probably depends on the separator model. At least with the Blue Sea 7622, provided it sees a charge potential (from either side) the separator should close and charge both battery systems. I removed the self jump start feature on my old Surepower unit and went with the 7622. Several of the Blue Sea models have control features built in such as full time open or closed modes, an automatic mode, lock out, and a trip out safety mode.
I'd test the separator. If you have a model with lockout feature, make sure it's set up for automatic operation and hasn't tripped or is in the open position. I also believe in monitoring and having a good gauge so you can read what is going on. If your charger is supplying a low amperage maintenance charge it is possible that what pulled down your engine battery is pulling more than what the charger is outputting. I would want to see if the shore charge is actually making it to the engine battery and at what rate.