Can BMS bypass increase the likelyhood of motor damage?

DIY Builds
#1

I have two boards based on Ownboard W2 and Wowgo 3X. Both boards use Hobbywing ESCs and both have rebuilt batteries with a BMS bypass for discharge (with a 40A fuse).

Right now each board has a busted motor. They are very twitchy / choppy when starting and accelerating. When testing boards upside down sometimes the motor gets stuck in a position where I have to give it a nudge or otherwise it won’t spin. I’m guessing the phases might be burnt out.

Both boards did have quite a lot of mileage before the battery rebuilds. Since then first board has made a few hundred kilometers before the motor failed but it’s a Mini board so I haven’t been pushing it that hard. The motor on the second died a maybe 100km after the rebuild.

So can a BMS bypass and burnt motors be related?

#2

ur sensor connector either unplugged itself, or motor sensor are busted

shouldn’t be

#3

I agree with @frame.b022, it sounds like a motor hall sensor problem

#4

I tried testing a motor by spinning it with a drill and measuring voltages on phases. Good motor showed around 10V AC on all 3 phases. On the bad motor only phase showed 10V while two others were around 5.5 V

#5

Motor sensors have nothing to do with the phase voltages, they are 5V and digital

Could you upload a pic of all the wires coming out of the motor?

#7

I understand, I’m just saying that I tested phase wires and I think the problem might be in there, not in hall sensors, but I don’t have much experience here.

A moment ago I also run another test when the motor got stuck I checked for continuity between phases and it was only on one phase, the other two were dead. On the good motor it was 3 for 3. Then I played around some more with the bad motor, moved the the shaft and wires a bit and now the bad one is 3 for 3 as well on continuity, it’s working good for now. This has happened before.

As for wires, there are:
blue, yellow and green thick wires for phases
blue, yellow, green, black, red, white thin wires for hall sensors and other stuff. I’m guessing one might be a temp sensor or something.

#8

Most likely hall, hall, hall, ground, 5V, temp, respectively

#9

With the motor stopped, the phase wires should always have DC continuity between all phases. Any other result would seem to suggest a broken winding or termination or test device/connection.

Sounds like this may be the path to investigate more

#10

I just rewired everything from the ESC up to almost the motor but not fully. I’m thinking maybe the issue is on that small length of wire I left sticking out of the motor.

I’m gonna look into that.

Thanks

#11

When you test the motor, make sure the ESC is disconnected from it

1 Like
#12

Try a BLDC hand test

1 Like