VESC suddenly cutting and resetting during acceleration

Ryuudan

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Joined
Apr 7, 2015
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52
Ok, I couldn`t find anything on the internet neither on the forum about this particular issue.

Whats happening:
When there's no load on the motor (ie wheels up in the air) and you try to go full throttle or even just around 60~70% the vesc freezes, blink the red LED 3 times and resets, after 3 seconds is working again.
When there's load it happens in a similar way, but sometimes I'm just holding my speed and suddenly one motor stops.

When put on BLDC software and real-time data there's no abnormal current spike, but there's a slight spike right before it cuts. I tried putting the limits higher and lower for current and voltage and it doesn't change the behavior.

I'm on version 2.18 and the VESC is a Chinese version with 2 caps of 470uF instead of the big one I've seen on Vedder videos and an aluminum heat sink.
my motors are way smaller than those used on skateboards. it's a 4114 750W 8S 29.6V, so I'm using around 25~30A max. They also have 24 poles instead of the usual 12.

It doesn't happen every time, so I can't figure it out.

I've used these VESCs with another motor that had 14 poles and was 4S 50A and it never happened with them.

any ideas? maybe it's the caps?
 
Best guess is your motor RPM exceeds the ERPM the controller can properly commutate.

So when it's unloaded and can spin at full RPM easily for a tiny throttle input, it spins up so fast the hall signals and/or phase current feedback is pulsing faster than the controller can keep track of, and the controller is trying to keep up by sending phase current pulses that fast but can't.

A lower pole count motor that doesn't cause the same problem in the same situation will produce and need less pulses for the same RPM so won't overwhelm the controller, which is why it may point to this being the problem you're having.
 
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