NOCO Genius GENIUS1 Mode D'emploi page 7

Understanding Charge LEDs.
The charger has one (1) Charge LED. This Charge LED indicates the connected battery(s) state-of-charge (SOC). See the explanation below:
LED
Pulsing Red LED
Pulsing Green LED
Solid Green LED
Maintenance
Green LED
Understanding Error LEDs.
Error Conditions will be indicated by the following LEDs.
LED Reason/Solution
Solid Charger is in Standby mode or Battery voltage is too low for charger to detect.
Solid
Battery voltage is too high for the selected charge mode / Check the battery and charge mode.
Solid
Possible battery short / Battery will not hold a charge. Have battery checked by a professional.
Solid
Reverse polarity / Reverse the battery connections.
Flashing
Charger internal temperature too high / Charger will resume function once the Charger internal temperature drops.
Charger ambient temperature too cold / Charger will resume function once the Charger ambient temperature rises.
Explanation
The Charge LED will slowly pulse "on" and "off" when the battery is less than 75% fully charged.
Bulk charge complete, optimizing battery for extended life.
When the battery is 100% charged, the Charge LED will be solid green.
After the battery is fully charged, the charger will continue monitoring the battery, and provide ongoing maintenance and
optimization. The 100% Charge LED will pulse "on" and "off" slowly during these cycles. The charger can be left connected
to the battery indefinitely.