New big motor, stuttering noise at high amps

rg12

100 kW
Joined
Jul 26, 2014
Messages
1,584
Hey Guys,

Finished upgrading my downhill e-beast.

I've got a big 9.2kg hub motor on a 24" wheel along with 21S LiPo and a 45A Greentime controller with the shunt soldered to the point I'm drawing about 100A (yeah it will explode soon I know...)

Well, first test on full charge, leaning on the handlebar to keep the front on the ground and of I go to pull full (scary as f***) throttle and suddenly I hear the motor stuttering with a fast "grr grr grr" sound each time I accelerate hard (doesn't happen while just riding fast).
* Hub is brand new and runs cool like the weather outside, even the cable is barely slightly warm.

What could it be?
 
I can't help you with your particular set-up, but I did something similar with a hub motor a while back, albeit only on a 15A controller.

Like you, I soldered the shunt, pulling around 25A from the controller. On acceleration it would stutter very slightly, until it reached cruising speed, where it was ok. I ended up removing a little bit of solder from the shunt, and it was fine from then on.

This leads me to believe you've soldered the shunt too much.
 
I think too much is not the problem...the motor can take it and the battery can provide it, so why the stuttering?
 
Yeah, 100A is over 2 times of what the controller can take, so... you probably popped a fet.

Open it up and give it a good sniff.. :lol:
 
Weird as it may sound, and this has been discussed years back... phase / hall wiring combo..it maybe correct, it maybe a 'poor' correct or a totally incorrect forward. no load battery current will tell you.

For some weird reasons, never explained, of the three' correct ' combinations, some times some tend to work better than others.

If all else fails it might be worth trying other combos, ...but after following up the sniff test with a proper FET test with multi meter..diode tester
 
No load depends on throtle...about 60-200w
Does the wiring combination still apply if you have a self learn feature in the controller?
 
Since it is a 'self learning' controller, that sort of rules out a wrongbwiring combo I'd have thought.
 
Checked wheel in the air wattage...
600w at 8A
normal for a 8kw lipo beast
 
I remember it was 300w on my 14S LiPo bike (45A controller) with smaller (yet still big) motor
 
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