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[Beau388]

I can only speak to my coach which is a 5 year old, plant 750 coach. There is a tap on the positive post of the chassis battery for an 4 awg cable. This runs to a 100 amp DC circuit breaker located on the frame rail just behind the battery. From the CB another cable runs directly to the house battery compartment which is located just behind the entrance door. The cable is connected to a Trombetta continuous duty DC contactor (relay) located on the back side wall of the battery compartment. A second cable goes directly from the contractor to the positive post of the closest 12 volt house battery. Across the contactor's activation coil's terminals is an Intellitec bi-directional relay with delay controller.
Product Description
The BIRD (BI-DIRECTIONAL ISOLATOR RELAY DELAY) performs two important functions. It provides a method of charging the coach battery from the engine alternator and charges the chassis battery from the
converter when the coach is plugged into shore power. When neither battery is being charged, the batteries are isolated from each other to prevent the loads of one battery from inadvertently discharging the other battery. The unit is housed in a plastic enclosure suitable for mounting under the hood, out of direct water spray. It operates in combination with a continuous duty solenoid to connect the two batteries at the proper times for charging.
There are terminals on the Intellitec controller for activation by an external switch. Plant 750 use these terminals for the emergency start switch. Wiring from the emergency switch has a 5 amp fuse.