I had a busy weekend but found the time to program a couple of ESC's (emax blheli 20A) to make them bi-directional, wired them in and set about tweaking my ROV code to centre the
motor stop position with my joystick centre position.
all was going well but the motor bearings sounded very noisy and then both ESC's burned out two of their FETs.
these are the same ESC as I use for the vertical thruster (which works fine) and have been flashed with the same blheli firmware so I suspect either the motors are producing excessive back EMF
when I stop them or the 48v-12v dc-dc converter supplying them doesn't respond quickly enough to load changes and produces over voltage spikes.
either way I'm hoping some capacitors will solve the problem.
Today I replaced the FETs on my ESC's with known good quality ones, the ESC's came fitted with a variety of different FETs, chinese floor sweepings maybe.
I'll see if they survive any better.
update-
having replaced the ESC fets all seems to be well, No more burned out ESC's and motors running well.
I have turned down another 60mm prop to 50mm so now just need to cram all the new wiring into my hull and seal it back up.
Looking forward to sea trials soon.
![Smile :)](./images/smilies/icon_e_smile.gif)