KT controller bobble under throttle

[harrys]

I got back a bike I had converted for a friend three years ago. 48V, 500W geared rear moyot and 20A sine wave controller. The throttle didn't work, (broken wires is my theory) and I replaced it. I noted he had put about 1400 miles on it, and the exposed controller (one of my early projects) was pretty dirty. Bike seemed OK, although it was noisier than I remembered, and the controller seemed warm, after going for a 1/2 mile ride..

I rode the bike for an hour and found a throttle issue, Bike will accelerate well under throttle, but as it gained speed, it would briefly cut out. The display remained lit up, and after the motor went silent, it started up again all the way to top speed (maybe 22 mph) Doubt that it's a battery issue. I was only rolling the throttle slowly. In PAS 3, I could hit the same max speed with no cutouts. . Yeah, I know. I'm running the bike too fast. My friend rides, he says, at 14-16 mph,

Before I return the bike, I want to understand this, Guess I will have to try a second controller.

 

[saneagle]

Does it do when cold or only after running a bit? What shows on the LCD at the time of cut-out regarding watts and battery charge/voltage?

The first thing I'd check is all the motor connectors because any fault with them could cause consequential damage. The problem is more likely to be throttle related. Maybe the wires are rubbing inside or there's a bad solder joint.

 

[thelarkbox]

Anything elw electronic i would suggest running it on the bench and looking for signs of overheating..
cant quite see how to do the same with an ebike tho as running under load for x miles is tricky to emulate..

 

[harrys]

Now I remember that I've seen it before. As the motor ramps up on throttle, it glitches around 13 mph and will keep running. This is a video from 3 years ago. As I recall, it was seen on my other controllers . Not seen on non-KT controllers. Only apparent on test stand, Not detected on my controllers already on the bike, so I figured the momentum of a wheel made it hard to see.

Now with the current bike, I can feel the momentary loss of power around 14 mph. I switched controllers, and the glitch was somewhat apparent with the wheel in the air but not when riding.