Sofirn C8F 21700 Sense Resistor Location?


Does anyone know where the Sofirn C8F 21700 Sense Resistor Location?

Got a pic?

Only ones from this thread till im back home Monday.

Nothing jumps out at me.

Does it use a sense resistor? Or is it “DD” through the FET? Vaguely recall people swapping out “small” FETs for “bigger” FETs, and all.

Eh, I’ll let someone else jump in…

No idea new to all this.

Are you planning some resistor stacking?

Yes that was the plan.

4R99 resistor looks to be the smallest on any of the boards, but that seems really too high to be a sense resistor. Why don’t you trace out the boards and draw up a schematic, then it might make sense how it regulates current?

If only I knew how,its a steep learning curve

i don’t think there are sense resistors to regulate current, looking at a datasheet for the 030L FETs it seems that limiting the Gate to Source voltage will limit the current across the possible range of Drain to Source voltages available in the flashlight.

If you could just trace the path from pin 4 of the FET back to the driver chip it may reveal some sort of divider circuit that limits the gate voltage. It would require a higher gate voltage to drive higher current, but there are system constraints that you can’t exceed. Or you might try measuring the gate voltage to see where you are operating—don’t know if this is your chip datasheet but it shows the limits.