kmiller - I need to make a correction. The solenoid located in the battery compartment is an auxiliary start solenoid, it is not an isolator. I have been unable to locate the isolator, but I did change the solenoid. It did not fix the charging problem.
I am going to replace the auxiliary start solenoid with a Redarc Electronics dual sensing smart start battery isolator 12v 200A I found on Amazon and at Etrailer. It is pricey, but it will fix the charging issue.
Your problem sounds like the house battery charger which is located in the compartment with the Xantrex inverter. Ours in the basement compartment left of the entrance door.
I hope this helps.
