I am trying to monitor a house bank and starter battery with my BMV 602. Does the negative from the alternator go to the "load / charging" side of the shunt or to the neg post on the starting battery? I know that I need a cable from that post to the "load / charging" side of the shunt, but I cannot find a clear schematic that includes the alternator. In fact, I have found contradictory schematics and need a definitive answer please!!
There should be nothing connected between the house negative and the shunt. This stops load from bypassing the shunt.
The far side of the shunt from the house battery should be grounded to the vehicle chassis/body. This gives the neg connection to the starter battery.
Think of it as two separate systems. Starter and house. They should share a common negative. Like building two houses next to each other. They share the same ground, but no connections between them.
Starter circuit and alternator are wired in a loop with starter battery. In a car the alternator negative goes to starter battery negative and from there to chassis/body. If it's a boat there's a complete negative circuit. Engine gearbox are also grounded to chassis/body.
Load side of shunt goes to same negative connections as alternator negative. This is the common/shared negative.
There should be no connections between house and starter systems on the positive side. With the possible exception of a cross charging system. Positive starter battery to monitor doesn't count for this rule.
So if there's no existing connection between these circuits, add one, after checking there's no accidental cross link on the positive side. Doesn't really matter where this is done, as long as there's a clear path to the starter battery.
Hope this clarifies.
