eBike Thermal Fuses

Swelling is NOT GOOD!!! a swollen cell (lipo?) will probably charge/discharge out of step with 'healthy cells in parallel leading to the groups early demise.. and could be the root of the issue?

Also similar symptoms can be the result of dirty or bad battery/sled connections especially idf the battery was plugged in/out when turned on in error. (or has no on/off switch..) wire wool cleaning and re-bending into shape any sprung connectors may resolve the issue?

Still dont like the sound of swollen cells tho perhaps post a pic or 2 so those in the know can comment with authority (not me)

btw afaik a thermal fuse is a one shot protection device, once blown it will not reset, for that behavior thermal switches are employed.

Harmonk said:

The battery has good charge and indeed starts to work on the bike for a couple of seconds then the entire supply cuts out and I have to stop get off the bike, switch the battery off then on again and it then works fine until I get going and the same happens all over again.

They are old batteries with 1-2 showing signs of swelling but as I said they hold charge and voltage (29V).

Click to expand...

Sounds like the BMS is doing its best to shutdown the battery to avoid catastrophic failure and fire, while you are ignoring the obvious signs.
Safely dispose of the battery.

In my opinion, it's an old battery that's sagging on voltage under load. When you try to use it, safety circuits in either the bike or battery sense a voltage drop and shut the bike down. When the load is removed., the battery recovers enough to start again, but dies immediately underload again. Both the bike controller and the battery BMS have low voltage detection circuits for this purpose.

The bike/battery sound like they are from 2010? It's time to replace the battery. They still sell 24V packs for a rack mount. It shouldn't be very complicated to replace the whole battery and cradle. If you're lucky. maybe you can even find the same battery for the old cradle, but I doubt it. You do have to compare the costs to replace the entire bike vs replacing the battery,

By the way, "XH259-10J Battery" brings up a number of different battery voltages and case styles. I assumed from looking at pix of Glide 1's that it's a 24V rear rack battery,

Update: Thank you everyone for your comments.

Here is a pic of the swollen cells which I know are not good and also the new BMS that I tried but still got the same effect.

So it appears that these old battery are sagging on voltage under load despite charging and showing a full 29V under no load.

I did see a replacement 18650 pack on AliExpress but this is unfortunately not available in the UK so I am starting to build my first 7s4p pack – wish me luck!