Sterling B2B negative cable

[Poutie57]

Just a quick question I have connected my B2b negative up according to Sterling’s instructions back to the starter battery but in doing so bypassing the victron shunt should I just wire it up to the shunt and not bother with the starter battery connection or wire to both

 

[Richard n Ann]

Put it on the shunt then the current will be measured

 

[autorouter]

As I understand it, the main positive current flow in a B2B goes from alternator positive to starter positive, through the B2B, to the leisure battery positive.

The negative return current flow is from leisure battery negative, through the shunt to chassis, along the chassis, then from chassis to starter battery negative and alternator negative.

The negative wire on the B2B is a low-power connection, simply to provide a negative connection for the electronic circuitry within the unit, in a similar way to the negative of the coil on a split charge relay. It needs to be connected to the starter battery so the unit can monitor the starter battery voltage accurately, without voltage drop errors.

Monitoring the voltage of the leisure battery, if required, can be done with a pair of wires connected to dedicated voltage sense terminals on the B2B.

So it's best to connect the B2B negative wire to the starter battery negative, or to the chassis as near to it as possible.

 

[Kannon Fodda]

If you have a Victron Shunt, only the habitation battery negative should be connected to the battery side of the shunt. You should have a single lead (quite meaty depending on overall current that could flow so probably at least 25mmsq) between habitation neg and shunt battery side. There should be nothing, even if you have a b2b, connected to the hab battery negative, other than the shunt. The b2b negative connects to the output side of the shunt.

 

[Poutie57]

If you have a Victron Shunt, only the habitation battery negative should be connected to the battery side of the shunt. You should have a single lead (quite meaty depending on overall current that could flow so probably at least 25mmsq) between habitation neg and shunt battery side. There should be nothing, even if you have a b2b, connected to the hab battery negative, other than the shunt. The b2b negative connects to the output side of the shunt.

That’s already in place it’s just where do I route the the neg from the B2b to the in side of the shunt as well as to the neg on the starter battery