question

ericcpearce avatar image
ericcpearce asked

Wiring Smart Shunt with two batteries and A/B/AB/off swicth

I'm adding a SmartShunt to a two-battery setup on an RV, and already have an A/B/both/off switch on the two batteries. What is the recommended way to wire the shunt? With the shunt be confused by the A/B switch?

SmartShuntwiring
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1 Answer
Kevin Windrem avatar image
Kevin Windrem answered ·

The Smart Shunt and BMV battery monitors calculate state of charge by counting current in and out of the battery. It needs to know the battery capacity to do this calculation. So if you switch batteries into the shunt it will count incorrectly and SOC will drift.

There is no real answer other than using separate shunts before the switch. But this complicates monitoring "system" SOC since Victron GX devices assume ONE battery bank as the system bank and one shunt to monitor it.

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