Kranked Kit with surging power


New Member
I have a version 2.0 kranked kit I bought used. It is about 6 years old. I have retrofitted it to an XC bike for the time being. It is all throttle controlled, pedal assist at my discretion. I have a 52v battery I keep in a backpack while riding. It has a Kelly controller which appears most similar to this KBS-x , though I purchased an adapter wire to run the Kelly software and it states that the controller is not supported. It is likely an old version of a similar controller no longer supported. If I understand correctly it does not have a torque sensor, which makes my problem all the more confusing.
The setup has plenty of power but does one weird thing. There is a surging which spins the motor up to higher rpms while the motor is under load. With that much power climbs can be tricky. I get a throttle boost when the trail gets steeper and chunkier. Once, this resulted in the bike rocketing out from between my legs as I crested a climb with a large root on the top. Luckily I landed on my feet. The maker told me the kit should run max speed at about 100 rpms at crank. That feels like the surging speed. (subjective I know) so I think it is generally running sub-optimally and then hitting 100% when counter-force is applied. I have tried a couple of things to remedy this
Eliminated connectors in battery wire connection
Adjusted the throttle sensor plate to be sure I ma getting a full signal
Using Kelly software to diagnose
No improvements with these steps. Hopefully this kind of problem sounds familiar to someone and I can target the battery or controller for replacement.


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