mtm12345
New here
Bike: E-Cells Five Star, 60V dual battery system
Motor: Hentach hub motor, peaks at ~2300W
Controller: KT60ZWSRLTD (40A, LVC 50V ±0.5V) — two different controllers, both behave identically
Display: KT-LCD8HU P V1.0 4GS 60V
Battery 1 (main): S-Spard 60V 19.6Ah 1176Wh
Battery 2 (secondary): Smaller second battery, less affected by fault
Battery balancer: Dual battery parallel balancer between the two packs
The fault:
Random power cutouts since the day the bike was new, continues two years. The display used to stay on during cutouts — now goes blank 9 out of 10 times. Sometimes during a cutout the display stays on but shows wattage to the motor while there is actually no power going to the motor.
Key observations:
Cuts out at 63.4V — well above the 50V LVC
Cuts out under load, while coasting, and while stationary
Much less frequent on secondary battery alone — rode 45 minutes before one cutout
5V sag under heavy load
Does not cut out at full charge (67-68V) but starts cutting out around 63-64V
Unplugging the motor completely does not cause a cutout
Wiggling all accessible connectors does not trigger a cutout
What has been done:
Controller replaced under warranty — new controller identical behaviour
Chafed wire at frame exit point found and repaired — no improvement
All P and C settings checked — P5 was set to 8, changed to 25, no improvement
C12 at 4, LVC confirmed at 50V on controller label
Wiggle tested every accessible connector
Battery holds charge perfectly, factory confirmed charge level normal
What has NOT been tested:
Individual cell group voltages inside main battery
Live voltage measurement at exact moment of cutout
BMS behaviour under load
Main question:
What could cause complete power cutouts at 63.4V — well above LVC — over two years, happening regardless of load, and now almost always killing the display too?
Any help greatly appreciated. This fault has defeated two controllers, the original manufacturer's tech support, and multiple local mechanics.
Motor: Hentach hub motor, peaks at ~2300W
Controller: KT60ZWSRLTD (40A, LVC 50V ±0.5V) — two different controllers, both behave identically
Display: KT-LCD8HU P V1.0 4GS 60V
Battery 1 (main): S-Spard 60V 19.6Ah 1176Wh
Battery 2 (secondary): Smaller second battery, less affected by fault
Battery balancer: Dual battery parallel balancer between the two packs
The fault:
Random power cutouts since the day the bike was new, continues two years. The display used to stay on during cutouts — now goes blank 9 out of 10 times. Sometimes during a cutout the display stays on but shows wattage to the motor while there is actually no power going to the motor.
Key observations:
Cuts out at 63.4V — well above the 50V LVC
Cuts out under load, while coasting, and while stationary
Much less frequent on secondary battery alone — rode 45 minutes before one cutout
5V sag under heavy load
Does not cut out at full charge (67-68V) but starts cutting out around 63-64V
Unplugging the motor completely does not cause a cutout
Wiggling all accessible connectors does not trigger a cutout
What has been done:
Controller replaced under warranty — new controller identical behaviour
Chafed wire at frame exit point found and repaired — no improvement
All P and C settings checked — P5 was set to 8, changed to 25, no improvement
C12 at 4, LVC confirmed at 50V on controller label
Wiggle tested every accessible connector
Battery holds charge perfectly, factory confirmed charge level normal
What has NOT been tested:
Individual cell group voltages inside main battery
Live voltage measurement at exact moment of cutout
BMS behaviour under load
Main question:
What could cause complete power cutouts at 63.4V — well above LVC — over two years, happening regardless of load, and now almost always killing the display too?
Any help greatly appreciated. This fault has defeated two controllers, the original manufacturer's tech support, and multiple local mechanics.