Hi guys!
I wrote about this to manufacturer, bet there is no response for 24 hours now and my deal is very urgent. So here it goes.
I have recently sold my old 500W cyclone kit with 24V 10Ah PSI battery. Initially it was 24V 20A (8s2p) battery, but during a fall I damaged one cell and had to take away all 8 cells and leave it in 8s1p configuration.
When I mounted the kit on client's bike, everything was fine for couple of days and then strange things started to happen: when throttle is on maximum, the motor shuts down after a few seconds (during acceleration). When accelerating, throttle power indicator is green and after shut off it changes to red (no orange). If I keep the throttle twisted, red LED flashes.
To get a better understanding of the problem, I connected oscilloscope to motor's power connector and saw that voltage is swinging very badly (26V +/-15V), due to power wire inductance, I think (length is about 50cm). Then I connected 2200 µF capacitor directly to motor's power connector and measured it again. The noise was greatly reduced, but it is still there. Please see attached images (max load):
First picture shows battery voltage while throttle is being twisted 0-100%.
Second picture shows a strange voltage drop, which I have no explanation for.
And the third picture shows a part of the same gap and PWM period is clearly seen (300 µs ~ 3 kHz (?!)).
I have scoped each and every cell while idling and during maximum load - none of them drops below 3,2V (3,3V idle). I thought a current may be to high and BMS is kicking off, so them I shorted BMS shunt - no improvement. Also I've scoped the battery directly on cells (before BMS) - same situation there. So BMS is not kicking it off and the problem is in motor. But where? There was no such problems when I was using this KIT on my bike.
Could you please advise where is the problem and how to fix it? I do have main electronics knowledge and proper tools, so I would be able to fix this. Is motor's LVC kicking off? I could easily disable it, as BMS has it's own LVC.
I wrote about this to manufacturer, bet there is no response for 24 hours now and my deal is very urgent. So here it goes.
I have recently sold my old 500W cyclone kit with 24V 10Ah PSI battery. Initially it was 24V 20A (8s2p) battery, but during a fall I damaged one cell and had to take away all 8 cells and leave it in 8s1p configuration.
When I mounted the kit on client's bike, everything was fine for couple of days and then strange things started to happen: when throttle is on maximum, the motor shuts down after a few seconds (during acceleration). When accelerating, throttle power indicator is green and after shut off it changes to red (no orange). If I keep the throttle twisted, red LED flashes.
To get a better understanding of the problem, I connected oscilloscope to motor's power connector and saw that voltage is swinging very badly (26V +/-15V), due to power wire inductance, I think (length is about 50cm). Then I connected 2200 µF capacitor directly to motor's power connector and measured it again. The noise was greatly reduced, but it is still there. Please see attached images (max load):
First picture shows battery voltage while throttle is being twisted 0-100%.
Second picture shows a strange voltage drop, which I have no explanation for.
And the third picture shows a part of the same gap and PWM period is clearly seen (300 µs ~ 3 kHz (?!)).
I have scoped each and every cell while idling and during maximum load - none of them drops below 3,2V (3,3V idle). I thought a current may be to high and BMS is kicking off, so them I shorted BMS shunt - no improvement. Also I've scoped the battery directly on cells (before BMS) - same situation there. So BMS is not kicking it off and the problem is in motor. But where? There was no such problems when I was using this KIT on my bike.
Could you please advise where is the problem and how to fix it? I do have main electronics knowledge and proper tools, so I would be able to fix this. Is motor's LVC kicking off? I could easily disable it, as BMS has it's own LVC.
