Hello! I actually have a P2V+, however I'm coming to the P3 forum, mainly because it's an issue that shouldn't matter between the P2 and P3, and there's much more traffic over here on the P3 forum.. Anyhow,

I haven't flown my drone in a good solid 2 months it's just sort of sat in its case. Anyhow, I needed to use it for something tonight, so I pulled it out. I started it, took it off as I nomally would, and the flight seemed to be fine. However, after about 30 seconds, the red lights started flashing rapidly on the drone, and I was like; "LOW BATTERY?!?! That battery said that it was full 30 seconds ago!" So I just assumed that it was the auto discharge feature built into the batteries, so I charged up the battery and tried again, and the same thing happened. I tried a different battery, and the same thing happened, then I tried a third, and that one seemed to be good, but after about 5 minutes of flying it did the same thing. I should also note that a couple hours after this flight, the batteries show that they have almost a full charge, even though I'd discharged them to what the had said was "16%" before, so it seems more that it thinks that the battery is draining faster than it actually is.

I've had this trouble before with a battery, but only one. I just assumed that it was that battery, but now pretty much all of them are doing it. Do I have 6 bad batteries on my hands?! Is there some sort of a reset I can perform? Any ideas are appreciated, thanks.

I think you need to calibrate your batteries. They have been sitting for a few months, calibrate them and then see how they act.
Best way since they've been sitting so long is a slow calibration, fully charge them then put them in the aircraft and power it up and leave them until the aircraft shuts itself off. Then charge them on your stock charger and see if you get a full flight.

Ok actually interestingly enough, I have two chargers. I tried certain batteries on one charger, and certain batteries on another, and all of the ones charged on one charger are bad, and all of the ones charged on the other are good. Interesting... If I continue to have issues though, I will try this. Otherwise, is my charger probably dead?

sigilwig44 Posted at 2016-2-21 15:31
Ok actually interestingly enough, I have two chargers. I tried certain batteries on one charger, and ...

Status update: I've seen no pattern on one charger working and another not working so well. Interestingly enough, I flew with one battery, and after about 3 minutes (when I landed) it said that is had < 12% charge. I just let it sit for about 15 minutes, and I looked at it, and it said that it has 87% charge! It seems that the batteries are thinking that they're draining faster than they actually are. I don't know if this is fixable or not. Does anyone know? I've talked to DJI service reps, and done a ton of research. I've tried a few things to attempt to fix the batteries. Here is what I've tried:

-Depleting batteries to less than 8% then charging them all the way up to 100%.
-Doing an advanced IMU cali.
-I've tried batteries on both chargers, and seen no pattern there.

I have 2 batteries that work well, and 4 that are terrible. It's extremely frustrating seeing that I can't seem to solve the issue. Is it possible that ALL FOUR batteries just quit? That's almost $500 in losses, suuuuuper frustrating. Also, do you guys think that the DJI service people could maybe repair the batteries somehow? Or maybe even me? The guys at DJI told me to reinstall the battery firmware. They said I could find a download and instructions online, but I don't think it's something that's possible. Is this something you guys have heard of?

So in summary, I've tried everything that I can find to try online. I've called the DJI service reps, and they can't really seem to shine any light onto the situation. It seems to be more of a problem with the batteries than the craft also. So here's what I need you guys to tell me:

-Should I try sending it in to DJI? If so, what are your experiences with the wait times there?
-Have you ever heard of reinstalling the battery firmware? If this is possible could you please tell me how to do it?
-Do you think that all four batteries are just simply dead?


Thanks for all the help.

sigilwig44 Posted at 2016-3-10 06:46
Status update: I've seen no pattern on one charger working and another not working so well. Intere ...

In your original post you indicated you had not flown in a solid two months,  took it out of the case, popped in the battery and away you went.
If I understand correct, your batteries were stored charged? Correct?
If so, this is likely the problem and those batteries are toast in that case.
Batteries should not be stored for long periods full or near full charged (they should not be left more than 10 days fully charged). Some of the P2  batteries will  auto discharge but some don't I suppose due to a firmware glitch that some have had or a battery firmware update not taking effect (so much for "intelligent" smart batteries)..
Anyhow, hook up to the Phantom assistant on your computer and check a good working battery against a bad, you will likely see a noticeable difference in cell voltage etc. from one cell to another on the bad batteries. There are lots of posts on the P2 forum on batteries.
Do not store them fully charged for more than 10 days!!, I believe the recommendation is not above 50%..
Oh, you never posted in the P3 forum....you are still in the P2 forum...

Good luck..

Alright, thank you for your help. Yes, you're understanding correctly, it was sitting for two months, I took it out, popped in the battery, and flew. Some of the batteries were stored charged, and some were not, however I can't recall which ones were charged and which ones weren't.

I wonder why the batteries wouldn't auto discharge? I've heard about the auto discharge before, but I've never seen it happen to my batteries. Hmm.....

I've numbered my batteries 1-6, here's the cell voltages of batteries 1, 2, 3, and 5. Battery one seems to be alright, but not great. I can get about 7 minutes of flight time on battery one, where on the really bad one (battery 2) I can only get about three. Battery 2, like I stated is awful, I can't seem to really get any more than 3 minutes of flight time out of it. Battery 3 has always been great, and so has battery 5. I can get a full 20 minutes out of these batteries. Here's all the numbers:

Battery 1:
        Cell 1 - 4003 mV
        Cell 2 - 4001 mV
        Cell 3 - 3959 mV
Battery 2:
        Cell 1 - 3961 mV
        Cell 2 - 3906 mV
        Cell 3 - 3908 mV
Battery 3:
        Cell 1 - 3955 mV
        Cell 2 - 4053 mV
        Cell 3 - 4027 mV
Battery 5:
        Cell 1 - 4074 mV
        Cell 2 - 4081 mV
        Cell 3 - 4071 mV

I should also note that these batteries were not fully charged when I took these numbers. I'm not sure if this matters. If it does let me know.

My main question to you guys is: do these numbers look normal? Does batteries 1 & 2 look significantly different to you than batteries 3 & 5?

I'm not sure how "big" of a difference I should see between the cell voltages. Thanks.
EDIT: Oh! One more thing... If the cell voltages are off, is there any chance of somehow saving the battery? Or is it just toast and basically good for nothing other than the garbage? Thanks again!EDIT: Forgot something else... My other question would be, do you guys think it would be worth sending it to DJI for repair? I'm going to have to pay for diagnosage fees, so would I probably just be better off trying so sell the batteries for like 25 a piece? I've seen bad Phantom batteries go for that much on eBay...