Adjust R2 to give 2.5V at the R input (about 8.6k ohm).How do I set the cutoff voltage?
That's determined by the choice of MOSFET for M1.how much current can this handle?
Why not?, there are numerous protection boards available, for very little money, and 5S are quite common.The problem with buying a production board designed for these batteries is that I have not found one that will work,
Are you sure there's no protection board inside the battery packs?, you need individual connections to each cell in order to provide a decent level of protection. There could be a low voltage shut-off in the tools, and individual cell protection in the battery packs.I am using a portable tool battery, and they have the shutoff built into all of the tools, to make the batteries cheaper.
It is the current through R2, R3, and R5 (assume the voltage at U1's cathode is about 1V when it is on.The reason I moved the switch is because I need as little battery drain as possible after cutoff...
Is their a way to calculate the drainage current after cutoff?