LockH said:
Hmmm... "60 percent or less"? Sorta interested that the cells seem to have degraded at a "faster rate" than I might have thought. "Shelf life" kicking in?
Tks
Hi, LockH!
Yes, I'm puzzled too... The battery is made of 7s5p 18650 LiMn cells. They are something around 2200mAh each to get to the advertised 11Ah total. Fancy green aquamarine color cells with no markings.
I opened the pack, when I bought the new bike, and rebalanced everything, since the bottom cell group, energizing the BMS, was off with the others.
I suspect, since the e-bike was on sale in fair quantity in a popular supermarket chain, that they got a stock, possibly 1 year old, maybe more, maybe less...
I also suspect, since the battery pack was having some strange reworked soldering, and retape of groups, that at a certain stage possibly somebody dismounted a large quantity of that battery packs and tested individual groups of cells, reassembling a fair amount of packs with the good ones, while discarding some amount of cell groups altogether.
I guess the manufacturer of that cells was testing a new chemistry and was having average quality control.
Initial 2 years with the battery were good... up to 60km range, good performance going uphill.
After that, range started to shorten, but now, after 4.5 years, uphill performance is ridicoulous and range is 30-35km top...
I assume it is due to a degradation of the Rin of the cell, mainly, because the charging time is still the same, but the controller hits easily the LVC for any reason... using MIN power assist, so minimum motor current, is best to have enough range, but the pack has clearly degraded. :?
I'll dismount the pack to see if it is just a cell group that is bad or the entire battery...
Eventually I'll build, out of it, a 6s5p or 6s4p pack for a minimoto I have in preparation... discarding the bad cells...
Maybe there is something I missed, since in the last 4 years I was busy with other things and I didn't follow the electric scene...
Have Fun!