I have 3 batteries and one day noticed one battery was completely dead, when I put it on charger nothing happens (no lights) . on /off charger or in drone--hit button once and no lights. What's up with this? Any way to recover it? Battery is only 6 months old and only been used 12 times.

Good chance the electronics within the battery failed rather than the cells.

Does dji have warranty on battery?

I think half year warranty on battery`s

CaptainET Posted at 2017-6-19 13:53
Does dji have warranty on battery?

Official warranty on DJI product batteries is "6 Months and Charge Cycle less than 200 Times".
Warranty information can be found here.

If you store a battery after it has been discharged - the monitoring circuit continues to draw the battery down until its totally discharged. If the battery reaches this state it cannot be recharged unless you disassemble the battery and hook the charger direct to the  battery terminals to get enough charge to run the circuitry.  

Regards  Mike

If it is still under warranty, go and put in the claim before you miss out. DJI batteries are probably 2 times to comparative OEM batteries in the RC world. Yet, the quality seems to be questionable given all discussions on the forum about dead and sick batteries. I log all my batteries for each charge and have found that the storage capacity deteriorate every recharge. It loses about 30mah each time. I would be reluctant to think that the battery will last 200 charges. What is the point if you only have 40% of total capacity, you are carry a lot of dead weight flying.

BoomStrike Posted at 2017-6-19 14:25
If you store a battery after it has been discharged - the monitoring circuit continues to draw the battery down until its totally discharged. If the battery reaches this state it cannot be recharged unless you disassemble the battery and hook the charger direct to the  battery terminals to get enough charge to run the circuitry.  

Regards  Mike

I have done this, and still no luck.

The battery now flashes 3/4 of lights as in 75% but it will not power mavic and not release any power  out of the battery.

It almost appears that the mavic battery circuit board will CUT All power if the board loses power at any time.
Perhaps someone can find a way to reset this board to accept the newly updated recharge.

Mine was brand new, stored for 8 months in the box, now its brand new trash... come one DJI