KT-22a controller surging on PAS use - new install

AHicks

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Guys, I've installed several KT controllers without issue, including an identical install as this one. This one is presenting me with a challenge I'm wondering if anyone else has run across. Using an LCD-3 display, 500w geared hub.

Seems to happen in any PAS level, but not when using the throttle. The "assist" indicator is flashing on and off in time with the surging, as well as the watt meter readings.

PAS sensor was working fine with the original controller. No hint of anything like this going on at that point.

All waterproof connectors, bike has never been wet, and it's only a couple of weeks old.

Scratching my head..... any ideas?

-Al
 
AHicks said:
Guys, I've installed several KT controllers without issue, including an identical install as this one. This one is presenting me with a challenge I'm wondering if anyone else has run across. Using an LCD-3 display, 500w geared hub.

Seems to happen in any PAS level, but not when using the throttle. The "assist" indicator is flashing on and off in time with the surging, as well as the watt meter readings.

PAS sensor was working fine with the original controller. No hint of anything like this going on at that point.

All waterproof connectors, bike has never been wet, and it's only a couple of weeks old.

Scratching my head..... any ideas?

-Al

have you tried reconfiguring it in the LCD3 C/P settings
 
I had one install with an LCD4 display that would give intermittent little thrusts rather than steady power when running on PAS. After trying different settings in the PAS parameters with no luck, switching from simulated torque mode to speed mode fixed the problem.
 
Chalo said:
I had one install with an LCD4 display that would give intermittent little thrusts rather than steady power when running on PAS. After trying different settings in the PAS parameters with no luck, switching from simulated torque mode to speed mode fixed the problem.

Sounds like what this one is doing pretty much. I do run them all in simulated torque mode (power based PAS vs. speed based). Performance is totally erratic. Current speed and load make no difference at all. Assist quits for a second, and may run 10-30 seconds prior to shutting off again. Surging is the best description I can think of.....

I run the KT controllers for the "simulated torque" mode/power based PAS. If there's an issue with the controller while doing that, it's of no use to me. That's my suspicion, that the controller is defective. I was hoping I was missing something as the idea of waiting for another to arrive isn't real attractive. (kid with broken new toy syndrome)

The PAS sensor is one of the newer sealed units. I don't think they're adjustable, but I guess I've never tried.

Thanks for your thoughts guys! -Al
 
izy said:
AHicks said:
Guys, I've installed several KT controllers without issue, including an identical install as this one. This one is presenting me with a challenge I'm wondering if anyone else has run across. Using an LCD-3 display, 500w geared hub.

Seems to happen in any PAS level, but not when using the throttle. The "assist" indicator is flashing on and off in time with the surging, as well as the watt meter readings.

PAS sensor was working fine with the original controller. No hint of anything like this going on at that point.

All waterproof connectors, bike has never been wet, and it's only a couple of weeks old.

Scratching my head..... any ideas?

-Al

have you tried reconfiguring it in the LCD3 C/P settings

Sorry, missed this on first pass. To answer as briefly as possible, I'll just say oh hell yes! That would include referring to the settings on another very similar bike with the same conversion, and doing a total reset/starting over again. -Al
 
Problem Solved- finally!!!!

After replacing the controller and riding with the new controller installed for a few miles, it became clear that the source of the surging issue had not been found yet. The controller (KT-22a) was not the issue. I replaced the cadence sensor on a hunch, one of the new style that's all sealed, with a KT cadence sensor, which is also a sealed unit. No more surging or weirdness. The new cadence sensor fixed it.

So even though the original cadence sensor was only a few weeks old, and had never been exposed to water from any source, it was defective. Best guess was the the rotor was slipping on the crank. A junk design that does not have enough grip on it.
 
Just dropping in here momentarily:

Recently I had a similar problem with the Cycle Analyst v3 on the SB Cruiser trike, whose throttle output signal runs two different controllers and motors at the same time. The problem was surging at lower speeds (above around 10-11mph or so it became smooth) when using just cadence PAS (throttle was fine), with the sensor as part of a TDCM BB (not using the torque sensor ATM). The surging did not match cadence or wheel rotation rate, etc., nor did it change rates. Something on the order of every half second or so, IIRC.

A few problems happened at the same time, causing different symptoms, but this one appears to have been caused by the heavy rain I was in the day before the problem started, as once the system fully dried out a few days later, the problem went away, just before I would have had time to troubleshoot it and measure / test things to find the root cause. :(

So at least it works now, but the only thing I'm pretty sure of is that the PAS sensor itself was the affected piece of hardware.
 
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