icecube57 wrote:The controller is bad yes, Im getting a GM Regen Controller to replace this one RMA through the company i bought it from.
But Its the bms cutting out early on the battery because the last time i tried a full discharge it stopped at the same exact AH which was 15.5. But the controller was good on my last full discharge. When I tested the cells through the bms they were rather high at 2.7. some a little bit lower but not near the full discharge state of 2.2.The voltage was around 46 when it cut out.. The lvc on a 48v controller is normally 41 sometimes lower if you get one custom made.
The vendor says its normal that the bms is protectecting the pack. It doesnt lug or anything i still have good solid 30mph performance all the way to the 15.5AH mark and then it cuts out. But i think the lvc is set so high to prevent full discharge from damaging the cells and pack. Its well designed and i can see why the vendor sets it that way. But I ordered a 20AH pack and im getting 75% of that and verified by a volt meter that the cells arent fully discharged. Im going to charge with the BMS and discharge without it and either let the lvc of the controller kick in or manually back off when it hits 40 to 41 under load i bet i get better results.
icecube57 wrote:I went out and bought a rc charger used on rc planes. Takes 11-15 DCV input. It can output 4.2, 8.4, and 12.6 volts. I used my regular charger to bulk charge it. I let it try to balance itself. I then disconnect the BMS/Balance connector. Inserted the charging pins into the appropriate connector holes for the given string i want to charge. It charges them up to 4.2v. The bulk charger doesnt let the cells get that high only up to 3.75 which is the bare minimum for charging lipo.
. Its taking a while to charge... about 1hr or more a string at 1 amp so I know they werent balanced. It shuts off and alarms when its done. I can charge at 250ma, 500ma, and 1 amp. This should help a bit with the capacity. After my repairs they were all discharging evenly voltage wise after i pulled 10AH out of them.... that was a rare sight. I knew there were runt cells when i repaired the pack but i had no way to charge them properly. And with the bulk charge it always cut off before the weak cells got full. It took several days for the voltages to come up to the rest of the pack.
Users browsing this forum: No registered users and 3 guests