Di-Directional Isolator

liborko wrote:
Check the voltage on Ignition terminal of the BIRD in normal driving. There might not be high enough voltage to keep BIRD operating due to voltage drop in the system. Your alternator might need smaller pulley to speed it up. Also the link you provided is for gasoline(4-pin) BIRD version 00-00362-00, you should use Diesel 2 version 00-00839-00 which has 5 terminals.

Wiring the relay coil directly to the ignition could result in situation when trying to start the engine starting battery would be heavily loaded by deeply discharged house battery. Better solution would be to wire coil thru the oil pressure switch so the relay would close after the engine was already running.

"Check the voltage on Ignition terminal of the BIRD in normal driving". wish I could, That terminal is a long ways from there drivers seat.

"There might not be high enough voltage to keep BIRD operating due to voltage drop in the system."

That's a good theory, And I'm checking the voltage on the Chassis battery with engine running. will be back with reading.
Good catch on the part number