Gotrax XR Elite BMS Replacement
Hey all. So I have a Gotrax XR Elite that I bought back in October of 2020. Bought a different scooter the following spring as my main one thanks to several issues and support being terrible.
Anyways, the scooter worked perfectly fine last year the few times it went out. Pulled it out of the basement last week for this season and it won't turn on unless plugged in, typical battery issue of some sort.
Pulled the battery out. Reading the battery leads, it's around 39v. Reading the xt60 off of the BMS reads 15v, so I would assume the BMS is faulty.
Looking to confirm these symptoms are indicative of a BMS failure and if anyone has recommendations for a BMS replacement since Gotrax doesn't have any batteries available.
Posted Mar 29, 2022, 9:04 PM UTC
Well, it certainly seems so - 39V in a 10S battery means 3.9V per cell, which is well within safe margins; the BMS should have no reason to cut power.
Then again, it could also be that one cell group has fallen below safe voltage while all the others haven't, resulting in the "clean" reading at the battery terminals. The only way to know for sure is to measure each cell group one by one.
I had measured each cell group. All were 3.9v except for one that was at 3.5v.
Ah, yeah, that'll cause the BMS to trip. The difference is quite large, that cell group is probably damaged.
You can try carefully bringing it up to 3.9 with a current-regulated bench power supply, but it's unlikely to solve much; you'll probably have to replace the entire cell group, if you're able to perform the operation. Otherwise you can get someone else to do it for you, but battery work is labour-intensive so it might be more expensive than it's worth.