Display shows battery full, but it is not


10 mW
Aug 6, 2022
I transferred my existing Bafang/Kt rear hub drive setup from my old trike to my new one and everything was working fine. The only thing I changed was resetting the tire diameter from 26" to 20". The battery had about a 35% charge so I did a short test ride. The display showed one bar in the battery status when I returned. After turning things back on, I took it for a 2nd test ride and the battery display showed 4 bars. I turned the display off and back on and the display showed one bar again. By the end of this test ride the battery status showed no bars. I shut the system off again and restarted a few minutes later. The display again showed 4 bars. I turned the display off and on again, but it still shows 4 bars even though the display has less than a 30% charge. Does anyone know what is causing this, and how I can fix it?
Some 36/48v controllers autodetect the battery type at startup. So if the battery is close to 36v full / 48v empty region, it may mistakenly identify it as the wrong one, and show the wrong meter readout.

Unless the controller has a specific setting to tell it only to use one or the other, there isn't a fix for it other than ignoring it when this condition happens, or recharging then power cycling the system to reset the battery choice.