Arlo1 said:A proper cap will still absorb this although you might see something at the fets it will be minimal compared to what you would have without.
exactly!
When the circuit is turned off under load, the voltage on controller side will jump instant to 0V (or at least very close to zero). than there is battery voltage + the voltage spike across drain and source on the FET's. a cap would help a lot for lowering the spike.