How to fix an electric scooter that won’t charge.
My Xiaomi 1S won’t charge due to a faulty battery pack. In particular, one of the spot welds on the LiPo cell connecting tabs broke.
NOTE 1 - The loose tab was not visible from the outside, it became evident only removing the wrapping of the battery pack and checking each tab one by one.
NOTE 2 - The loose tab was not visible from the outside, it became evident only removing the wrapping of the battery pack and checking each tab one by one.
I’ve got my Xiaomi Mi 1S electric scooter back in 2021 and been using it as my daily ride ever since. It has seen some 1500km so far, requiring little to no maintenance (a couple of flat tires). Few days ago, I hooked up the battery charger, without paying attention that the LED on the charger didn’t change to red (stayed on green). I came back the next day to a scooter that I believed was fully charged, just to find out that was not the case on my way to work. I barely made it to the office and, as I got there, I plugged the scooter once again. There I realized that the charger wasn’t charging the battery at all.
Checking online I realized the many ways an electric scooter can let you down. Specifically around the battery these are the most common failures I’ve found:
- failing charger
- failing charging port (at the scooter) (see 1)
- faulty BMS (to be replaced)
- tripped BMS (fuse to be replaced)
- broken battery (e.g. loose, disconnected or broken tabs) (see 2)
For me, it was a battery tab that was not doing proper contact anymore. The most intriguing part was that from the outside all the tabs seemed perfectly fine and the tab came loose only after the battery was unwrapped. The red LED on the BMS was blinking though, indicating an error with the battery (for an healthy battery the blinking LED would be blue).