QCMan wrote:
Sounds more like he is having an a/c switching issue as he states that the shore power is good. I cannot help on that one.
Llittle info and lots of possibilites. I agree but doubtful the pedestal power was checked at the time he has the problem. It's likely his problem but...
OP Recommend you buy a plug in 120V meter and check the voltage inside. You can buy an inexpensive VOM from Harbor Freigh but be aware that probing 120V AC can be dangerous should not be done without full awareness of safety procedures.
Thoughts - try a different site. What does "fades to battery mean"? Do you hear any relays clicking?