BJR981S
Well-Known Member
Same thing happened to me with my Air two weeks ago over the ocean. 40% battery, 12 satellites, everything going great. Inexplicably, battery dropped to 0%, RTH engaged, then force land. Luckily, wind helped get it to within 20 feet of shore. SPLASH!!! Recovered and used Refresh Express to get a replacement very quickly. They replaced the battery as well. Thing is, I have two batteries purchased with the fly more combo and I'm petrified to use them (over water especially), not knowing the outcome. I have a dispute in process with DJI as I don't believe I should be charged a replacement on the DJI Refresh account, as it was a product defect, not pilot error. I will update. Thanks for posting.
This I see only to frequently and generally relates to not following the DJI precede for fully discharging the battery and then recharging it to calibrate the % battery "Fuel Gauge" and / or the over discharge of a battery to eek out that last few minutes of flight time.
Your battery condition will depend on how deeply your are discharging the battery. Never go below 3.7V on a cell unless you are doing the calibration procedure. Discharging below this level reduces the number of cycles that the battery can perform and reduces the actual stored watt hours of the battery capacity. The results are w=hat you describe. The "Fuel gauge" is inaccurate as it is not calibrated and the battery has the potential to collapse a cell. i.e. go from a reasonable percentage to a small percentage very quickly. Unfortunately when it does this it has also reduced its C rating and can not deliver sufficient current to continue to hold the drone aloft.
I think this is why DJI have difficulty applying warranty in these cases.