I'm about to buy a P3 Advanced with 2 brand new batteries. The drone is 7 months old, and has never been used. I'm concerned about the batteries.... They have never been used since the time of purchase. Could it be a problem? Don't they go automatically to "hibernation mode" if not used for a long time? How can I check their state? I'm thinking of fully charging them, then opening the DJI Go app and checking the battery status... but maybe I shouldn't buy them at all. What's your thought on this? :-)

They should be OK, lithium batteries can last 10 years, but it is wise to be very careful until they have proven themselves.

Charge them to full, leave them for a day, check that the voltages on the cells are all reasonably close (green), then discharge them with the motors running on the ground down to 8%, check the voltages between cells are still all reasonably close.

If any of the voltages don't match then maybe repeat the test a few times to see if they will recover and match up.

If they do match then you should be OK, but P3s do sometimes fall out of the air with battery problems so I wouldn't discharge them in the air by more than 50% for a few flights while watching the voltages.

Remember that the % may not be correct for the first few flights, never let the voltages reach 3V on any cell, by then it will be too late to land.

Nigel_ Posted at 2017-6-10 02:16
They should be OK, lithium batteries can last 10 years, but it is wise to be very careful until they have proven themselves.

Charge them to full, leave them for a day, check that the voltages on the cells are all reasonably close (green), then discharge them with the motors running on the ground down to 8%, check the voltages between cells are still all reasonably close.

Thanks for the tips, I will be careful. :-)

The biggest problem with long term storage of these so called "smart batteries" is that they continuously draw a tiny amount of current from the battery for the smart board. Eventually if stored unused for long enough the cells will drop below the safe minimum and damage occurs.
It's best if you can get them out and give them a tickle every now and then.