Like a lot of people here, my new drone battery would not charge on the drone slot (just one light, far left, blinking for hours and hours). I took a chance and bought the 3 battery multi charger by Autel from Amazon for about $52. The battery immediately started charging...and was fully charged in about 90 minutes. A properly charging battery shows light 1,2,3,4 blinking in sequence, then going solid over time as each segment gets charged. After that, the battery also seems to be charging inside the drone...as it should have done to begin with. I think some Autel batteries just need a kick in the a$$. Sucks to be out $52 extra, but better than boxing up and returning all the gear and hoping for an Ebay refund.