Engine battery draining

[PhilAsztalos]

Hello, my class A Coachman sports coach seems to always drains the engine battery when I'm just running the house lights or fans for example.

 

[Neal]

bad battery?

 

[widdershins]

I'd start with the isolation relay, assuming it has one of those it should be keeping the chassis battery disconnected from the coach when the engine isn't running.

 

[calvin99]

The first thing I always install on an RV is a proper battery monitor. Without one, it's difficult to know a battery's state of charge and what's consuming its energy. I prefer Victron products although there are other less expensive options
Battery monitors - Victron Energy
YOu can't go wrong with the BMV-712 or SmartShunt. The SmartShunt is essentially the same as BMV-712 but uses a smart phone rather than a separate display.

 

[John&Andrea]

I’m thinking Neal is on track. Possibly a bad battery. If you have a charger try hooking up and slow charge.

 

[PhilAsztalos]

Thank you so much for the feedback. My inch and batteries as well as the house batteries all charge when I am plugged in 50 amp. I have checked them with my tester and I get a strong 13 volts when they're fully charged. Again my problem is what I'm not connected to your power the house lights and fans seem to drain the engine battery every time. I will look into that isolation relay make sure it is not staying connected all the time.

 

[TheLooks]

Are you sure that you have the batteries identified correctly? You don't say that the coach batteries are dead as well. Why would the coach drain the chassis battery(s) and not the coach batteries? Look for a selector switch perhaps. Or perhaps something else is draining the chassis battery(s). Disconnect a terminal and check for a draw with everything off and then start turning things on.

 

[Boat Bum]

Be sure to test the batteries under load for more accurate assessments, they could be marginal but show full when tested w/o load.