Focbox DRV Blown - Video + Metr, what happened?

I got a metr pro today, man this thing is awesome! gotta take it out tonight to test the modes, overlay stuff, etc- at least that’s what I was thinking.

Boom! The DRV is blown.

The motor now has lots of cogging resistance when connected to that one focbox with the blown DRV. If I connect the first two phase wires, the motor spins fine, but if I connect the third far right one to any others, resistance to the motor spinning. Is this normal behavior for a blown DRV?

If I can get this focbox fixed, what should I do to prevent this from blowing again? I got a ton of over current faults right as it happened… super high negative current. I thought maybe the motor phases shorted so I disconnected all the phase leads and both motors spin normal and have the same resistance values between all phases on both motors, only the one focbox with a blown DRV.

Should I have used my cap bank to prevent this? Any ideas what I can do to prevent this in the future? The focbox is almost two years old and has never given me any issues.Thanks for the help guys.


If the motor spin freely white disconnected phase wire than the focbox shorted the phase wires somewhere on the pcb.
No idea thou from what it came. You run 12s,13s?


10S, 80A battery/80A motor per focbox

Than extra caps shouldn’t be needed at all.
Maybe it was just time for the fb to say goodbye.
When you checked the phase wire resistance, did you also check resistance to ground ( like the shaft or bell somewhere where there is no color)?

93kph? What?

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Another reason I hate you left, @Skatardude10 lol. Corey isn’t fast enough.


no … I swapped to imperial and it came up as kph so it’s all fucked.

:sunglasses::sunglasses::grin: 10char

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Yep, checked and no contact to ground anywhere on both motors and all the resistances look good across both motors.

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Sometimes shit just breaks. Happens a lot with Focboxes, I know from experience

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Your focbox still working?
Think i’ve got the exact same with my 6.6 it works “fine”, but one of the motor has way more cogging on the side of the probably issued vesc.
While braking i Can feel that it turns differently than the other motor, it’s not turning 100% freely.
And got those Over voltage faults too

what’s your absolute max set to? abs overcurrent is usually abs max… or it was for me at least

Think you’re right, was set on 80a, now i’ve set it to 150a

That sound…

So sad :c

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