The battery is charged but the unit isn't turning on. Remove the battery from the unit and examine the prongs and connection on both the battery and the unit to make sure they aren't damaged. Damaged prongs can cause the unit not to start up due to a faulty connection. Related articles Why Isn't my unit turning on? My mower is not starting up. What are some potential issues? Can I power this unit with my 24VBAT-XR8? Will any battery fit onto my unit? How do I adjust the cutting height on my Sun Joe Mow Joe MJ408E Lawn Mower?