I see alot of people here use the anti-spark softwitch for their boards. I’ve also seen alot of people posting that they blow the mosfets on them and the switches get stuck permanently on. The fix is super easy and more people need to know about it.
Recently the switch i was using blew two of the three mosfets onboard. The mosfets are wired in parrallel and are surface mounts. An acceptable replacement for the built in mosfets are these: https://www.digikey.com/product-detail/en/nxp-semiconductors/PSMN030-150B,118/568-5950-1-ND/2531237 (150v, 55.5A, $1.80 each). When wired in parrallel these give a total switch spec of 150v, 166A. Simply solder these in place of the blown ones and you fixed your $50 switch for $5.
I have ordered the mosfets myself and they are shipping, i will update this thread when i receive them and see how they work.
I theorize that the mosfets blow due to the lack of a capacitor or resistor in the circuit on the input line and the mosfets suddenly being saturated with voltage when a battery is plugged in (notice there isn’t an actual anti-spark circuitry inside, the mosfets are expected to handle it all on plugin). I will personally be wiring an anti-spark xt-90 before my softswitch so that the resistor can suppress the spark. A large capacitor or two on the input line would also work. I would also use a better sealant, on the switch i have it was gunked with some sort of calk that didn’t seem to transfer heat too well, you may want to consider using something similar to CPU heat paste for a better heat transfer.