I decided to make a Battery Managemet System using the cell-log 8s/m.
Those little cell/battery voltmeters have an alarm port that can be triggered at a selected voltage (battery pack voltage or cell voltage). I made a simple circuit exploiting this feature.
In the video you can see my prototype circuit to cut the load using the cell-log alarm port. When the threshold voltage is reached the alarm port closes the circuit and the mosfet opens the circuit.
I used a 12v 50W light bulb as load.
The battery is a 5s4p 18.5v 6Ah li-mn.
The alarm is set to go off if any cell goes under 3.79v. You can see the light bulb flashing as the alarm start going off. This is due to the fact that the voltage of cells goes up once the load is cut.
The alarm(s) can be set to go off to any value within the cell-log specs.
The next stage of the project is to cut the load permanently (no more flashing) as the fist alarm goes off. Then I will add the possibility to connect more cell-logs to manage a bigger battery.
The beauty of this system compared to a standard ebike bms is that there can be no current limit (depending on how/where the load is “cut”) so it’s suitable for high power setups.
A big “Thank you!” to my friend Adriano for helping me out with the circuit.