If all LEDs around the power indicator light up, the full power is available. That's the rule, you rarely ever see ones beeing off.
In normal operation, there are two different cases in which they still go out from time to time and thus the performance is limited:
- When the battery is fully charged, it may happen that the LEDs in the "charge" area are not all on. Than you havn't got the full regenerative breaking power available. After the first few 100 meters all LEDs should be back on. See also charging power at > 80%,
- If the battery is at <1%, it's going to slowly be limited to keep it from not discharging to fast.
Just because the LEDs are not all on, that does not mean you have to spare the battery somehow now. The BMS does it on its own, the LEDs are just a information about how much power you have at the moment. It limits independently to the still available power. No matter how hard you step on the pedal, the pointer never goes further than the glowing LEDs. (-> see also battery protection)