Most of the time, it means you need to charge the battery as it is at a low charge level but it could mean several things. First thing you need to do it put a voltmeter on the battery, if the voltage is less than 13.28V, the LED light will flash to let you know to charge the battery. If the voltage is above 13.28V and flashing, then you could have a weak cell /a cell out of balance/or defective cell and you need to contact EarthX for a warranty coverage if it is less than 2 years old. The LED will also flash if the voltage is too high, above 14.6V. If the light is solid and remains on for more than 10 minutes, then it is an indication of a BMS electronics problem and contact EarthX. LED LightVoltagePossible CauseRecommended Action Slow Flashing (5s on/5s off)Less than 12.8VBattery over-discharged (due to faulty charging system)Charge battery. Once charged, the light will stop flashing. Slow Flashing (5s on/5s off)Less than 13.2VWeak or failing cellCharge battery. If voltage drops below 13.2V within a few days, discontinue use. Slow Flashing (5s on/5s off) (> 1 hour time period) 13.2V-14.6VWeak or failing cellDiscontinue use. If in flight, this is not an immediate issue unless it is in conjunction with a charging system failure. Slow Flashing (5s on/5s off)Greater than 15.2VOver-charging (due to faulty charging system)If in flight, shutoff charging system immediately. Aircraft over-voltage protection is required if alternator charging system is greater than 20 amps (i.e. over voltage crowbar circuit) Slow Flashing (5s on/5s off) (< 30 min. time period) 13.2V – 14.6VCell to cell charge levels are not balancedMay come on briefly during periods of high current charging until the cells are automatically balanced. Try charging with a plugin charger, like an Optimate Lithium charger. Solid LightAny voltageBMS electronic issueDiscontinue use. If in flight, this is not an immediate issue unless it is in conjunction with a charging system failure. Solid Light that turns off after 3 minutesAny voltageShort Circuit protection was activatedNothing needs to be done. Short Flashing (2s on/2s off)Any voltageHigh battery temperature (> 65°C / 150°F)Let battery cool down prior to cranking or charging.