Battery & electrical questions

coolmom42 wrote:
I have a 2014 Coachmen 21QB on a Chevy 4500 chassis, with an Onan 4KW generator.

*Does the generator have its own starting battery? If so, how is this battery charged? Or does the generator crank off the chassis battery? (I'm assuming it doesn't crank off the house battery, as that would kind of defeat the point of having a generator.)

Most generators do use the coach batteries for their starting power, at least in my limited experience. Disable your coach batteries, and try to start the generator, as a test.

coolmom42 wrote:
*Does the generator charge the chassis battery?

No, usually.

coolmom42 wrote:
*Does the chassis alternator charge the house battery? If so, how well?

Yes, usually. Depends on the alternator amperage, ambient temperature, and size of the bettery bank to be charged. In general, I've always found it decent, if you drive enough between coach battery usage.

coolmom42 wrote:
*Does the battery isolator switch completely isolate the house battery and chassis battery from each other?

It's usually a diode (one way only) switch that allows simmultanoeus charging of all batteries, but that won't allow the coach battery system to borrow power from the chassis battery, so you (in theory) won't kill your starting battery by drawing power fromm it to run the coach 12V DC loads.

coolmom42 wrote:
*Does the converter charge the chassis battery when the RV is plugged into shore power?

Usually, yes.
EDIT: As per Matt, usually no. My bad.

coolmom42 wrote:
*On the side of the engine compartment, there is a 200 amp fuse. What is this for?

No idea. Sorry.

This is anecdotal info based on motorhomes I've owned, and my experience and understanding of their power systems, and your questions.