Hover dynamo E8 error.

Hello

I bought a used dynamo and I get the e8 error at end of cycle (when low charge) and the display also will say 3 bars then zero than 2. Seems like an awful lot of fluctuating. It seems odd enough that maybe they're connected? Honestly it was a fluctuation that made me think maybe there was a problem and that's not just the display telling me to plug the thing in