Problem with battery cutting out on hills.

[Danniford]

Hi, I recently acquired a fairly new second hand Windsor powacycle. The bike is in great condition . After charging the battery ( LiPo battery) gives around 28v on a voltmeter. On the flat the bike goes well, however on a hill the battery cuts out after a couple of minutes ( battery lights all go out). The battery is completely dead and reads almost zero on a meter. After an hour or so the lights come back on when you turn the key and voltage is back up to 26-28v. I have checked all fuses are secure and key switch operates ok.
Any ideas?
Thanks

 

[Deleted member 4366]

Simple: Knackered battery.

If you have electrical/electronics experience, you might be able to fix it, otherwise start looking for a new one.

 

[Danniford]

Some electronics experience - willing to give it a go - I did suspect the Battery management system might be cutting in and out but not sure why it takes so long to 'reset' ( switch back on again) I have taken a reading from each cell in the battery and each one is the same ( no obvious dud cells).
Any advice appreciated.

 

[Deleted member 4366]

Some batteries just wear out. The cells have very little capacity and sag a lot under load; however, if that were your problem, I'd expect it to switch on after a few minutes.

With your sort of problem, you need to be able to test the cell voltages under load to see whether they're OK or not. For that, you need a battery tester or put your bike in a turbo trainer.

If your battery were out of balance, you could re-balance it, but it isn't. The only thing you can try would be to mount a permanent voltage display meter where you can see it, so that you can see battery voltage in real-time. This will show if you have normal voltage sag or not.