Unusual Motor Behavior- Who has seen this???
 

I just finished setting up my 3rd ebike and I am having a problem. I purchased a 48v Luna shark pack and I have paired it with a Chinese 1000w non-geared hub motor. It is throttle only with no PAS. It has an LCD control.
The issue is intermittent glitch in the power while riding. I say glitch because it is more like a bump and not a pure loss of power. It seems like one set of coils gets out of phase for a split second and causes the motor to jolt. I have already ruled out the battery since I get the same intermittent problem with a different battery. I believe it is a loose connection, interference between cables, or a bad hall sensor. I have checked all the connections visually. I am sure it is not the main power connector. I can rule out the brake cutoff since that behaves differently (smooth cut in power.) That leave me with the LDC display control, the throttle cable or the hall cables/sensors.
Given all this info, which of those is the most likely culprit? Which would be the most sensitive to inductive interference? This may be a tough nut to crack and I am hoping someone has seen this exact issue before.
Many thanks,
Robert

Intermittent problems suck. You got 4 major components: battery, motor, controller and display. You eliminated the battery. Do you have access to working units of the other 3? Swap them out, one at a time. If you are using the brake wiring unplug it to be sure a switch isn't flakey. I doubt inductive interference is the problem. More likely a bad or melted connection going on & off as the bike vibrates. Good luck.

Thanks man!
R

I get a similar problem, and have eliminated just about everything apart from the battery, I think.
It seems to mostly occur when the battery is down a bit, never on a full charge. My battery is pretty old but still comes up to virtually the same reading as when new. Its a 36v and on a full charge it is floating on the charger at 42.3v. (Used to float at 42.6). However when it drops when used to about 35.8v its about then I get the dead spot. On the controller thats one bar down. If I turn off the charger and turn it back on again, I can usually get another 20kms or so out of it before another restart is necessary. A local battery 'expert' reckons the battery has a faulty cell.
Batteries here in NZ are about $800 so am putting up with the problem until I cant, then I guess Ill bite the bullet, buy a new battery and hope that solves the problem but am still getting 40-50kms on a full charge and as I rarely need to do that am living with it.

Power cables can induce spikes of current on data or other cabling. Be thoughtful when routing those cables. try to avoid bundling power with any others. Like the hall effect sensor. Shielding is good too.