Help with my folding ebike which cutting out under load .

[msf1344]

Hello everyone
I have a 36v 250w folding e bike which recently have a problem . The brand is Green Zebra Cycles and was purchased 2013 since then it was a great bike . it has a bafang rear hub motor . The problem started last week when I tried to go to work and noticed the bike was cutting out under the load when i am seating on it but when try the full throttle when the wheel was off the floor it was working fine at top speed without any issue . please help

 

[Nealh]

The battery is knackered , tell tale sign is under load and the 9 year age of it.
Nearly any knackered battery will work with no load.

Simply wire up a meter to the battery wires and watch the voltage under load on a ride, one will see the voltage sag heavily or in your case just collapse to 30v.

 

[msf1344]

The battery is knackered , tell tale sign is under load and the 9 year age of it.
Nearly any knackered battery will work with no load.

Simply wire up a meter to the battery wires and watch the voltage under load on a ride, one will see the voltage sag heavily or in your case just collapse to 30v.

Hi , Thanks for your reply . I should mentioned in my post , I have tried a brand new battery which borrowed from my friend and the result was the same also I checked the motor with similar bike and the motor was fine . if you look at the image the bike is runnig in full throttle when the wheel is off the floor .

 

[wheeliepete]

Hi , Thanks for your reply . I should mentioned in my post , I have tried a brand new battery which borrowed from my friend and the result was the same also I checked the motor with similar bike and the motor was fine . if you look at the image the bike is runnig in full throttle when the wheel is off the floor .

Have you tried your friend's new battery on a ride out, using the throttle? As already mentioned, testing with the wheel off the ground proves nothing.

 

[Nealh]

No further response came from this one.
Full power with wheel off the ground tells you little as no meaning full current load is applied, one needs to know how the voltage reacts under load on the move. The only way of knowing is by wiring a meter of some kind to find out.

 

[msf1344]

Have you tried your friend's new battery on a ride out, using the throttle? As already mentioned, testing with the wheel off the ground proves nothing.

Hi sorry for a long reply , I was abroad for work commitment for a long time . Yes tried my freind new battery on mine when I tried it outside and I seated on the saddle and try to move the bike in lowest power mode but it was cut out with new battery too .

 

[artspeck]

Have you checked the magnets for alignment with the pickup sensor and are the magnets clean?

 

[msf1344]

Have you checked the magnets for alignment with the pickup sensor and are the magnets clean?

Hi yes its clean and perfect , anyway I used throttle and its the same result .

 

[Nealh]

Try your battery in your mates bike if it is ok , then the controller must be faulty and voltage regulator has had it.

 

[msf1344]

Try your battery in your mates bike if it is ok , then the controller must be faulty and voltage regulator has had it.

I think you are correct , I tried my battery on my friend bike which is similar and it was ok . so is there any chance so i can repair the controller by myself ? do I need to change one of the mofset ?

 

[Nealh]

If there is a dodgy mosfet one needs to do the test first to see if one is at fault.

 

[artspeck]

Hi yes its clean and perfect , anyway I used throttle and its the same result .

The first bike I had a similar complaint with it turned out to be a faulty ignition switch. Replaced with a new one and no further problem

 

[msf1344]

The first bike I had a similar complaint with it turned out to be a faulty ignition switch. Replaced with a new one and no further problem

You mean ignition switch on the battery ? I already said I tried my battery on other bike and it was fine .