Hello, I've happily put on about 5000 miles over 5 years on a yosepower KT-based rear wheel system.
I've had one or two breakdowns in that time, but now I am having a time diagnosing/fixing this latest one. (Still very happy with the system)
It's a KT controller attached to a bottle-style 36V battery, with KT-LCD3 display.
On Friday, bike gave a judder and quit, electrics off. Holding the power button makes the display light up for almost a second, before it shuts off.
Thinking this was some type of short-circuit protection kicking in, I went into diagnosing mode, disconnecting, isolating, simplifying.
In all the tests in the next paragraph, everything else is disconnected, including motor, but also PAS, brakes, etc. I've tried with each of them connected, and the behaviour doesn't change, so assume they're all unconnected in the below.
I replaced the cable between the battery and controller. Same behaviour.
I replaced the KT-LCD3 with a KT-LCD4. Same behaviour.
I replaced the actual controller with a KT-compatible no-name one off amazon. Same behaviour!
All permutations between new and old parts have been tested as well. The LCD display can light up momentarily, almost every time.
The only thing left un-replaced is the actual battery pack. This battery pack fits is the bottle-style type, where the controller is in the mount. In the replaced-controller tests, I directly and correctly attach the new controller to the +/- of the battery pack.
I faked the battery by using the battery charger hooked up to the controller (42V/2A), with the controller and LCD display only. Obviously I can't/shouldn't hook up the motor as the current draw would be too much for the charger. This happily powers the LCD controller and I can press buttons on it, change settings, keep it alive for as long as I want.
The battery pack was partly depleted on Friday due to riding around. I of course charged it overnight. It charged up, the charger LED was green in the morning, from being red (charging) before.
The little 5-led display on the battery agrees it is fully charged.
A voltmeter on the +/- of the battery itself gives 42.1V, which should be perfectly fully for a 36V battery.
I was originally blaming the controller, since many posts on here talk of leakage current through the controller mosfets giving enough power to almost power the display, even though the battery itself can't give much actual power when turned on, but I replaced the whole controller with a different one.
How do I best test the battery? Have tools including a good fluke multimeter.
The blade fuse in the battery was good. I can test the cells inside for equal voltage. Can the BMS inside the battery be at fault here?
Can I just wire the battery pack to some incandescent bulbs in series (to drop the current to e.g. 5-10A) as a load test, or will that freak out the internal battery circuitry?
Thanks for reading this long post! I can add more details/tests if helpful!
I've had one or two breakdowns in that time, but now I am having a time diagnosing/fixing this latest one. (Still very happy with the system)
It's a KT controller attached to a bottle-style 36V battery, with KT-LCD3 display.
On Friday, bike gave a judder and quit, electrics off. Holding the power button makes the display light up for almost a second, before it shuts off.
Thinking this was some type of short-circuit protection kicking in, I went into diagnosing mode, disconnecting, isolating, simplifying.
In all the tests in the next paragraph, everything else is disconnected, including motor, but also PAS, brakes, etc. I've tried with each of them connected, and the behaviour doesn't change, so assume they're all unconnected in the below.
I replaced the cable between the battery and controller. Same behaviour.
I replaced the KT-LCD3 with a KT-LCD4. Same behaviour.
I replaced the actual controller with a KT-compatible no-name one off amazon. Same behaviour!
All permutations between new and old parts have been tested as well. The LCD display can light up momentarily, almost every time.
The only thing left un-replaced is the actual battery pack. This battery pack fits is the bottle-style type, where the controller is in the mount. In the replaced-controller tests, I directly and correctly attach the new controller to the +/- of the battery pack.
I faked the battery by using the battery charger hooked up to the controller (42V/2A), with the controller and LCD display only. Obviously I can't/shouldn't hook up the motor as the current draw would be too much for the charger. This happily powers the LCD controller and I can press buttons on it, change settings, keep it alive for as long as I want.
The battery pack was partly depleted on Friday due to riding around. I of course charged it overnight. It charged up, the charger LED was green in the morning, from being red (charging) before.
The little 5-led display on the battery agrees it is fully charged.
A voltmeter on the +/- of the battery itself gives 42.1V, which should be perfectly fully for a 36V battery.
I was originally blaming the controller, since many posts on here talk of leakage current through the controller mosfets giving enough power to almost power the display, even though the battery itself can't give much actual power when turned on, but I replaced the whole controller with a different one.
How do I best test the battery? Have tools including a good fluke multimeter.
The blade fuse in the battery was good. I can test the cells inside for equal voltage. Can the BMS inside the battery be at fault here?
Can I just wire the battery pack to some incandescent bulbs in series (to drop the current to e.g. 5-10A) as a load test, or will that freak out the internal battery circuitry?
Thanks for reading this long post! I can add more details/tests if helpful!