loading
2CommentsJoined March 18th, 2017

Tell us about yourself!

Complete Your Profile
  • AlexanderK176 commented on boffinry's instructable EBike LiFePO4 Battery Troubleshooting2 months ago
    EBike LiFePO4 Battery Troubleshooting

    I think I figured it out - my pack became unbalanced and the BMS is not able to re-balance it. Possibly the BMS isn't able to discharge fast enough, or it's faulty, or I'm not waiting long enough (weeks?). Maybe the BMS unbalanced it in the first place, stealing power from a few cells, I'm not sure. The only thing I do know is that its safeties work - both upper and lower voltage limits.I plan to add two 6S JST connectors to use a cheap external balancer should this ever happen again. I only use (and thus charge) the e-bike occasionally and that probably gives the pack enough time to go out of balance.My other option was to replace the BMS, but all the options I found were in China and they listed very slow balancing discharge rates in the specs (70 mA at best)

    View Instructable »
  • AlexanderK176 made the instructable EBike LiFePO4 Battery Troubleshooting2 months ago
    EBike LiFePO4 Battery Troubleshooting

    Thanks for the instructable. I'm looking for a little advice after following these steps.I have a 12S5P 36V 15Ah pack made out of blue 25560 cells that are 3000mAh each. Pack was purchased from China in late 2012. Past few years the e-bike range went from 35 miles to 5 miles (to LVC, and it would cut off at about 37-38 volts). I finally cut it open and performed the following tests:1) Fully charged, all 12 sets had the same voltage (~3.3v) 2) After LVC, 9 sets were still basically full (3.2v), and the remaining three were different: ~3.0v, ~3.0v and ~2.6v. The troubled sets are numbers 2,3 and 10 in the series order.3) I separated the troublesome sets and charged the 5 individual cells one at a time on a B6 charger (set to LiFe mode, single cell) - and all of them took about the sa...see more »Thanks for the instructable. I'm looking for a little advice after following these steps.I have a 12S5P 36V 15Ah pack made out of blue 25560 cells that are 3000mAh each. Pack was purchased from China in late 2012. Past few years the e-bike range went from 35 miles to 5 miles (to LVC, and it would cut off at about 37-38 volts). I finally cut it open and performed the following tests:1) Fully charged, all 12 sets had the same voltage (~3.3v) 2) After LVC, 9 sets were still basically full (3.2v), and the remaining three were different: ~3.0v, ~3.0v and ~2.6v. The troubled sets are numbers 2,3 and 10 in the series order.3) I separated the troublesome sets and charged the 5 individual cells one at a time on a B6 charger (set to LiFe mode, single cell) - and all of them took about the same amount as indicated by the charger (3300 mAh). I expected at least one to have reduced capacity...The BMS checked out (no voltage between negative terminals)... So what can produce this behavior? Since all the sets are getting properly charged (at least charged to the correct voltage), what could lead to uneven discharge if the capacity seems good? Can I blame the BMS for this somehow?Thanks for any help!

    View Instructable »