Lipo charging

[michael]

Charged my new core Lipo 3250 battery for first time using the core udc 20 charger all very straight forward until i tried to charge it at club meeting after running a few heats with it. The charger came up with an error msg telling me one of cells was low i think. Not sure what i was doing wrong using same volts and charge suggested as when first charged,can anyone help .