Battery not charging (from chassis or generator)

MrWizard wrote:
lights and water pump work, when the generator is running

converter is working

Not necessarily. The pump and lights will work fine at 11.5 volts from the batteries alone.

Sounds like he has a problem with a "battery solenoid"......or some loose or broken wiring as mentioned.

A voltmeter is required to isolate the problem.
A fix at an RV shop probably won't be too expensive either.