I have an automatic dual battery system that self isolates below 12.7 volts and re-connects when one battery is 13.1 volts for 90 seconds. Will a smart shunt work with this system? I figure it won't read the second battery when it disconnects at 12.7v. Would I want it on the starting battery side, or the "house" battery side that disconnects to power stuff like the fridge, lights, etc?
After doing some more reading, it looks like I can use the shunt on the "house/accessory battery" and then use the aux input to the starting battery so if the batteries disconnect, I can still keep track of the voltage on both.
I'm hoping someone can chime in that it will work before spending the money on it though.
Smart shunt will measure current, voltage and calculate SOC for a single battery bank. For a second bank it will simply measure voltage.
Measurements for the main bank are through its negative cable, except for voltage, so correct connection is important. Only the shunt connects to this negative terminal. There must be a common earth/ground/negative between the battery banks. In the case of the main battery this is on the load side of the shunt so that no current bypasses the shunt.
The shunt will be permanently wired to both battery positives. The shunt isolates these two positives, drawing its power from the main bank.
So yes this may work, based on what you've posted here. But only if there's a common ground/earth. You need to check the combiner to see if there's complete isolation of positive and negative. Or simply positive. If positive only, that's OK. If both you need to check with the combiner supplier to see how they recommend that you resolve it.
