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Showing results for tags 'charging voltage'.
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I received my KS-18XL in June 1, 2019. This is my first wheel ever, amazing fun, been riding it for a month, 727 km done on it. I started reading about battery packs and how to keep it fresh for a long time. Should I charge to 100% or just 80%? Only then did I notice that my wheel would only charge to 85%, it would stop charging at 80.7 V, then later settle down to 80 V. Started debugging, maybe it's a faulty charger? KS-18XL has two 20s3p battery packs connected in parallel. I noticed that if only one is connected, the wheel charges normally to 84 V, if only another is connected, it only charges to 80 V and shuts off, the charger shows green light. The voltage would indicate that only 19 cells out of 20 are working. After communication with the seller and seller communicating with Kingsong we decide to try to rebalance the cells. I didn't know the cell balancing connectors are in the corner, so I removed the whole cover. If someone needs to balance their battery back, you don't need to open it all. I noticed the board had physical damage and first assumed it was me who had somehow damaged it during the disassembly. I was all dismayed so didn't document this part very well. Later after thinking more and more I realised it couldn't have been me, it had to have happened in the factory. 19 cells out of 20 were all showing equal voltage (3.8V), but the 13th cell was showing 0 V, exactly the same cell who's BMS had been damaged. Kingsong has told the dealer they would be sending me a new battery pack, so I am happy with the service, however it will just take a long time to reach me so the riding season might be over Will update if I do receive it or not. This story does sound awfully similar to @FrankFilmer incident. His wheel only charged to 70%, which I think is a huge red flag and indicates battery problems (maybe only 18 cells working out of 20). Finally, I think that our wheels are inherently very dangerous and had my board been damaged in another spot, or had I kept riding the wheel without paying attention I would have eventually gotten a cut-out or a fire in my home. The wheel doesn't have any advanced battery management system, it should watch the health of all cells and it should warn the user that the battery is malfunctioning, but there is no such warning for the user. I was riding with 19s3p and 20s3p battery backs connected in parallel. That can't be good. Always make sure that the wheel charges to 100% and actually check that it reaches the voltage it should be reaching. Just because charger shows green, doesn't mean all cells are working.
Have we ever considered that the real charging voltage for our EUC's batteries is not the same coming out from the charger? Every battery pack has its BMS, and the charging voltage entering BMS reachs the batteries through a diode (that blocks the returning current to the charger). This diode cause a voltage drop of about 0.6 or 0.7 volts. So, the real charging voltage that goes to the batteries is not 67,2 volts but 66,6 or 66,5 volts. And IMHO this is good because results in a lower stress and a longer life for the batteries.