NACHBIKE Electric Bike Lithium Battery

Only problem I have with the nach s1 is that my charger don't shut down after the battery is fully charged.its not shutting down because I don't think my battery is charging to its full capacity.i can't see my volts on this bike so I don't know but if the BMS isn't shutting the charger down it can be reaching its full capacity.other than that it's a great beautiful little bike it's not that little but it's a great bike ty freego I love My s1