A while ago, I wanted to use my Ninebot Elite after a long long time (over 6 months). It did not start at all! The only thing that happened after I connected my charger was a flashing, empty battery symbol on the displat of my Ninebot. I contacted Segway but the were not very helpful. As I was pretty sure the battery was gone, I tried to find a replacement. I contacted a few dealers and there was one that had a battery in stock. As these Ninebots are a few years old, I assumed the battery they were trying to sell me were old as well. And the quoted me a battery for EUR 1400 !!
Inspired by member NinebotPTRELITE+, I rebuilt the battery of my Ninebot Elite. I bought 60 LG INR18650-M29 2850mAh - 10A cells for EUR 130 and some spacers to build the packs. I viewed some Youtube videos about battery spot welding and bought a portable, battery operated one via AliExpress.
Next thing was to open up the original battery (it opened very easily), and disconnect al leads from the two battery packs. Of course I documented (photographed) everything very well and checked and double checked the positions and polarity of the new built packs. After a lot of spot welding and soldering, I protected the two packs with shrink wrap and put them in the original enclosure. I closed the enclosure with black tape and installed it on my Ninebot Elite to charge it (outside in case it catches fire).
The next moment was filled with pride and joy! It immediately started to charge!
I left it charging for several hours before I started the vehicle. All worked well! I did not ride it very long but I'm sure it will be as good as new!!