Chris- for the future you can make your own BIRD out of two Intellitec "Isolator Relay Delay(s)" and a continuous duty 12V solenoid. The Intellitec part# is 00-00629-120
. The gizmo has 3 wires, 12V in, charge voltage "sense", and 12V out when activated. It trips after 13.3V on the sense wir for more than 12 seconds, which indicates charge voltage is available.
You put 12V to both 12V in wires, sense wire to starter battery from one relay, sense wire from other relay to chassis batteries, both 12V out wires to one side of the solenoid coil, and the other side of the solenoid coil to ground.
Then 2/0 welding lead jumpers from starter battery 12V and from house 12V to the fat studs on the solenoid.
Voila! When either alternator or generator/charger kick the starters or house respectively to 13.3V- you get cross charging. Now you have a driving backup for a failed alternator, as well as a standard two way charging coach under standard conditions.
And the IRD's are potted for use in wet conditions so you can mount them wherever it is convenient.