Motor cuts out, resetting battery fixes it for a bit

[Ivan20]

I've got an ebike that's worked for about a year now, and for the past month and a half I've been unable to use it because every few minutes the motor will cut out entirely.
At first, it was cutting out every half hour or so every couple of trips. Then, the time I was able to ride got shorter and shorter. Whenever it happens unplugging the battery from the controller and plugging it back in gets it working immediately. Then it cuts out after a few more minutes have passed.

I've already tried replacing the wiring between the battery and controller, I have a new motor that was installed after the issue began, and the controller has no visible issues when i took it apart.

Anyone have any ideas what the problem could be?

At this point I'm thinking it's a bad battery, but I don't have a multimeter to test anything with. Gonna save up and get a replacement, but eh, winter is coming so it's not too important.

Controller: ebikes.ca C7225-GR http://www.ebikes.ca/c7225-gr.html
Motor: leafbike.com http://leafbike.com/products/e-bike-hub-motor/gearless-20-24-26-700c-28-29-inch/newest-26-inch-48v-1000w-front-hub-motor-wheel-882.html
Battery: http://www.ebay.com/itm/48V20AH-LITHIUM-LiFePO4-BATTERY-PACK-POWER-FOR-EBIKE-FREE-CHARGER-NEW-CELL/281571516784

 

[amberwolf]

Leave the battery on it's charger any time it is not in use. It may take days to weeks to re-balance it, assuming it is not a really bad cell, just one that's a little lower than the others.

If you watch it and see it indicate charging, then indicate full, then wait a while (hours, probably), then see it indicate charging again, you don't need to do anything but leave it hooked up until this doesnt' happen any more.

If it does not ever resume charging after the first shutoff, then you have to unplug and replug the charger (from/to wall *and* battery to be sure) to get it to restart charging for balancing (because it is not correctly designed for the battery), and do this each time it shuts off. You mght have to wait up to several hours before you plug it back in, though.


Alternately you can look up the many other battery repair (or bike/motor cut-out) troubleshooting threads, many of which have directions on disassembling the pack to test and measure it, if you want or need to go further than the above. (you may not need to, as long as the charging eventually balances it).

 

[dogman dan]

Nothing to lose now by charging it 20 times to see if it helps. Or 10 if that's all it takes. Charge, unplug from charger, let sit half an hour for the bms to bleed down high cells, put back on the charger.

If the charger will not re start after half an hour, then its less likely your problem is just out of balance.

Chances are though, if your battery is over two years old, it's nearing the end. It might be saved enough to use as extra range in the next summer. Paralleled with a new battery of same voltage, it might add capacity by not having to pull the whole load anymore.