Problem with 48 Volt 1000 Watt Rear Hub Ebike Controller

T

tailer

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Hello,

I recently boughta48 Volt 1000 Watt Rear Hub Ebike kit. After mounting and traying it around for few times, everything was fine.
After few km the controllerswitched off. I thoughtfirst that it was the battery because after unplugging and plugging again the battery, the bike worked for few seconds, but it was not. I changedthe battery and Ihad the same problem. I changed BMS from 20 A to 40 A in the case was a BMS current problems, but still not working. It seems it switchesoff when there is a big lead to push, like an acceleration or going uphill, it doesn'tdo that when I lift the bike and let the motor run at its max speed.
Can anymore help?

Thanks a lot

Fatjon
t 1000 Watt Rear Hub Ebike Conversion48 Volt 1000 Watt Rear Hub Ebike Conversion
 
20A was definitely not enough, 1000W at 48V is 21A and possibly more at peaks. Personally I wouldn't go under 60A. What battery are you using? The controller specs match with the motor specs?
Sounds like overload protection or massive voltage drops under heavy load. I think battery, controller or BMS (or a combination) isn't up to the job.
 
If you can, try to measure the voltage of the packs when under load. Also, if possibly, measure the amp draw under the same conditions.

You could probably just take and strap the wheel to a bench so it doesn't turn. That way you can test it under load without needing to ride it, or have the bike go all KITT on ya :p
 
It was the fuse, very sorry for wasting your time. I wonder how I could get power? I had the fuse on the negative wire that goes on the BMS, but this one was still giving me power.
 
If the fuse would be doing its job then it would trigger under load and you won't be able to get any power unless you rewire or replace the fuse. When power was still coming through then the fuse didn't trigger (and probably isn't the cause of your issue) or it fused short which sort of defeats the point of a fuse. Or is it a resettable fuse maybe so it resets when cooling down?
 
tailer said:
Hello,

I recently boughta48 Volt 1000 Watt Rear Hub Ebike kit. After mounting and traying it around for few times, everything was fine.
After few km the controllerswitched off. I thoughtfirst that it was the battery because after unplugging and plugging again the battery, the bike worked for few seconds, but it was not. I changedthe battery and Ihad the same problem. I changed BMS from 20 A to 40 A in the case was a BMS current problems, but still not working. It seems it switchesoff when there is a big lead to push, like an acceleration or going uphill, it doesn'tdo that when I lift the bike and let the motor run at its max speed.
Can anymore help?

Thanks a lot

Fatjon
t 1000 Watt Rear Hub Ebike Conversion48 Volt 1000 Watt Rear Hub Ebike Conversion
Click to expand...

Hello Fatjon,

I think I bought the same bike controller. I haven't build my full battery pack yet and have been using the lawnmower battery. My controller has a dropout at 40V which is easy to draw down to under heavy load. I suspect that when using high current you are causing a voltage drop and the controller is shutting down to protect itself. The condition remains until a power on reset, that is you unhook it and reconnect and it works.

I agree with the other users - you need some more power. (same as me).

Jeremy
 
A 20A chinese BMS to a 1kW ebike kit wont do it long run. A controller that like that can easily peak 40A or more. A chinese BMS is rated at 2x what it can do. You should atleast have a 60A chinese BMS on that one to play it safe.

When the BMS sense high current, and it will on startup when it peaks, the bms will shut down the power to the system or just burn out!

A bms will send through some power even when it triggered but not enough to run. You can see voltage when not loaded with anything.
 
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