question

@Mojo Not sure what exactly your question is. Are you asking about the ground lead of the BMS and whether it connects to which side of the battery monitor shunt? If the BMS is connected to an inverter/charger with an ethernet cable, you do not need a ground lead, as the ethernet cable provides the ground. See photo below. This is from the VE BUS BMS Manual page 10.

If you do not have an inverter charger connected then the ground lead would connect on the load side of the shunt as seen in the next pic. This is from the VE BUS BMS manual page 9

Having the power and ground on the load side of the shunt will also assist in tracking State of Charge, but the BMS draws very little power, about 10ma, so it's negligible that the shunt will track that anyway.

Hope this helps, Ron

Hi thanks for the reply.

i probably didn’t make myself clear with the question

I’m referring to the battery - cable on the BMS. which in my system is connected on to the negative side of the shunt.

The reason I asked the question is that I’ve seen It stated many times that only the battery negative should be connected to the negative side of the shunt. Anything else at all must be connected to the load side of the shunt.

But as you say the BMS is such a tiny load its unlikely to make any difference.

mojo