So with the rocker, you can push MOM and now the solenoid closes, then you turn the key to "Start" and instead of the solenoid opening as when powered from the engine battery, it stays closed from being powered by the house battery?
So you should turn off the heater fan etc yourself to reduce the total drain on the house when starting?
As I understand it, when pushing and holding the spring-loaded MOM side of the rocker, it manually (from you pushing and holding the button) energizes the solenoid from the house batteries. It does not care what the key position is.
As long as you hold MOM down, the house and engine batteries will be ganged together. Normally you turn the key to start the engine at this time, and when the engine is running, you release the MOM button, whereupon the rocker returns to the center "off" position, and the charging solenoid disengages.
Yes if your house batteries are low then you might want to turn off house energy users to maximize what the house batteries can do.
Steve
