Good morning
I introduce myself my name is Chris and I have been using DJI drones for my photographs and my movies, I bought various DJI products and I have never had problems everything works perfectly, I recently bought a pair of used mavic pro batteries but still in good condition, one works properly and its duration in flight and about 22 minutes would not hurt, the second unfortunately immediately gave me a problem that does not seem very common but has already happened to other users, and is the blinking of first led, the one farthest from the button, a sequence of flashes about 16 then a stop of 7 seconds then another 16 blinking, looking in the various forums the result I got is that the battery would be sent to DJI for repair. So no short-term solution, since the batteries cost me relatively little I decided to take it apart and to see if there was a problem visivamete the battery does not report any signs of failure, but measuring with a tester the voltage of each cell I found that two cells had a value in volt of 1.7 and 0.8, therefore very low perhaps due to a little use and to a storage in a cold place, ovidely, these two causes are not good for the battery and therefore the battery would result from throw, obviously I'm sorry to throw a semi-new and freshly purchased battery
So I tried to recharge it with a charger other than the DJI, of course I had to remove the battery and get to connect my charger on the positive and negative poles of the battery, setting these values
3 s cel
3000 mA

The measured voltage was about 6 V, then slowly when about 10.2 V the problem of led 1 flashed and 16 times disappeared and remains fixed to indicate the percentage value of the battery charge, I took the battery around 11.8 a bit more than its nominal value.
Disconnecting the battery I found that the cells were now 3.7, 3.3 V and all the leds were lit up regularly.
I tried to do an avolo with this battery and the flight time was about 20 minutes, not bad then I connected it to the original DJI charger and everything worked well.

Glad you solve the problem. Please pay attention to the message from app. If there is any error message, I would not recommend you continue to fly with the battery. Thanks for your support.

DJI Elektra Posted at 2018-3-18 00:56
Glad you solve the problem. Please pay attention to the message from app. If there is any error message, I would not recommend you continue to fly with the battery. Thanks for your support.

Good morning
Unfortunately, the weather has not allowed me to fly anyway I still checked the boat these days through the app and I have not encountered problems I made a domestic flight a few minutes but everything seems to work at best, however I think the problem is to be found in some faulty cell of the battery pack

Nomad04 Posted at 2018-3-18 02:22
Good morning
Unfortunately, the weather has not allowed me to fly anyway I still checked the boat these days through the app and I have not encountered problems I made a domestic flight a few minutes but everything seems to work at best, however I think the problem is to be found in some faulty cell of the battery pack

It will probably have a much lower life cycle than a normal battery, it was a used battery and paid a few pounds