Magnum Premium LS power cuts out randomly


New Member
Sometimes when I am starting from a dead stop, the power will randomly cut out; the motor won't run (pedal assist or throttle) but the display will still be on, and to fix it, I have to reset the controller. This happens seemingly at random, but usually WHEN I AM CROSSING THE STREET. It happened once in a parking lot with a heavy load of groceries, so it would seem to be related to load, but there doesn't seem to be a way to prevent it. Pedal assist 1, pedal assist 6, gentle throttle, strong throttle... there is no way to make me immune to suddenly having no motor at an intersection while I am trying to quickly get across in the limited time I have before the cars come at me.... It never cuts out in the *middle* of climbing a steep hill. Only the miniature hills from the curved shape of the road make my bike quit.
The controller is c6 and it's set to eco mode and capped at 20 mph. I believe it's the original premium, not the II. I got this bike a month ago and have rode 200 miles on it so far.


Well-Known Member
I had a similar problem (not on Magnum) and the problem was the cadence sensor.
The magnetic plate was relocated slightly so that it couldn't sense the crank rotation.
I don't know what kind of cadence sensor you have though?

Also, symptom that you're describing can be anything.
Maybe the connector on the motor / sensor is loose?