Hey guys thanks for the reply and clearing things up for me can i use mosfets in parallel? im just gonna switch it on and off no pwm i just dont want it to heat up without any heatsink . I have 15 of irl8748 so can i hook them up in parallel or can i use irf8788?
Thanks
forget the "without heatsink" - that irl8748 have 5milliohm RDson (ok. 4.8mR - but that's 5
) so you'll have 12,5W heat dissipation on the mosftet @ 50A - without heatsink it will last something like few seconds
paralleling mosfets is ok, but you have to ensure that the current will be evenly distributed - you need mosfets with same Rdson (or compensate with series resistors) and make PCB traces or wires of equal length.
but you'll be not able to run those without heatsink anyways... approx 1-2W is "safe" for TO220 package without heatsink... so no way.
another point is the Rdson vs. Ugs - that mosfet is "logic level" , but to achieve the low Rdson you need to drive the gate with 10V
and don't forget the peak volatges during switch-off even a 30cm wire have enough inductance to generate nasty voltage peaks during switching off 50Amps - so be prepared for those peaks
and last but not least ... reliable switching of 50A is kind of "electronics alchemy", definitely not something for young players