Flew my mini 3 Pro with no problems was down to 25% battery , my usual level before I manually RTH. Packed up went home . Next day recharged battery, showing 4 lights in multi charger hub , but dead in drone. Contacted DJI , they explained problem they asked for video of battery showing 4 lights but dead in drone, sent them the video had a reply asking me to kill the battery by drowning it in a 5% solution salt water for 12 hours and send another video showing it underwater, did all this and then DJI sent me a voucher for a free replacement. Should have mentioned that battery was less than 12 months old. The entire process took less than 48 hours for DJI to replace this battery. It was more than very easy, very pleased with service, cheers Len