Colin and Ricardo have pointed out a few flaws, reversed electrolytic capacitor which is a typo, slow and puny protection diodes. Right Oh. No large electrolytic capacitor on the controller board. Right Oh. Someone criticised parallel power fets. Is that so bad?
The over current protection is not latched off permanently until overload is removed. OK not so good.
I still don't see the fatal flaw to cause it to go bang.
My friend is intending to control an auto pilot motor in a small fishing boat. The motor will run for a few seconds in one direction, stop for a second or so and run for a second or more in the other direction.
No speed control but later on my friend will add a soft start circuit to produce narrow pulses around
300/400 Hz, gradually increasing in width to full on, over a period of a second or so to prevent the steering gear being knocked around too much by the motor. That is just an added refinement that would be nice but not essential at this stage because the main concern now isThe fatal flaw that we can't see!
I give up. Do tell.
Regards, John Crighton Sydney