We have a battery system installed in one of our vehicles to run a a/c system in the bunk, I have just installed a smart shunt to monitor the batteries but I’m not sure if I have it set up correctly.
The system consists of 2 5kwh 25.6v lithium batteries wired in parallel which are charged from a 160A alternator.
I have set the app up following instructions from this page but I think I have something messed up as the battery is showing full charge at 22.99v and this has not increased even after running the vehicle for about an hour.
Could somebody please check my settings and help me out?
Your settings look reasonable but a couple of minor changes, 4% for tail current may be a bit better and the charged voltage should be 0.2V below the absorption voltage. Assuming the alternator charges to a typical 28.4V to 28.8V you want the charged voltage at 28.2V to 28.6V. Be guided by what voltage the alternator generates. I assume you have 4 batteries in parallel, if so 390Ah is correct.
When the shunt starts it can start at 100%, it does not base SOC on voltage, but synchronisation of the shunt to 100% when the battery is full. It then counts energy in and out. If your battery is at 23V it is empty, you need to charge it up until it is at 28.4V (or whatever manufacturer recommends) and the current falls below 16A so it is fully charged. If you mean the alternator is running but the battery voltage is not going up then you have broken the circuit to the battery or the battery BMS has shut down.
Thanks for the tips, I have updated as you suggested.
I must have something missing with the wiring as the app is showing no current while charging, but when the unit is running it shows negative draw.
I have the negative cable from the charger connected to load minus on the shunt, and only the battery negative connected to the battery minus, I am guessing I need to add the earth from the AC unit itself but not sure how to do this without removing the earth altogether to connect it onto the shunt.
