The BCC will prioritize charging power. With the engine running all alternator power stays with the chassis until the battery reaches at least 13.2 VDC. At that point the BCC will tie in the house batteries and start charging them also. Works in reverse when plugged in concerning the house batteries and the converter is happy. When you close the AUX START relay on the dash you're doing the same, cross connecting the two battery banks together so you can force charge off the alternator or get the generator running if the house batteries are dead. House batteries start the generator on the Hurricanes.
I have the tech manual for the BCC if you want a copy (PDF format). Send me a PM with your email address and I'll reply with what I have.
One idea to keep in the back of you head, the battery disconnect solenoids can and have failed and will either leave to stranded, kill the engine while going done the road or defrost the fridge and everything inside for you. Doesn't happen very often but can. If you know which power points are which in the BCC you can bypass the dead solenoid with standard jumper cables until permanent repairs can be made. Had the chassis solenoid die in the driveway. First problem I had with the coach.
