OK - I'm on my fifth battery. 1 and 2 autoland after somewhere between 50 and 65% - never sure exactly when its going to happen, so I have 'retired' those (round contact). Bought three more. One of those started autolanding at around 65% 'sometimes'. It has 42 cycles. I wrote DJI, who responded that the batteries should be good for 300 cycles, unless I am 'abusing my battery'. All batteries are out of warranty.
Lots of questions here -
The first two became unreliable after less than 70 cycles. I did leave one of these fully charged for a long time (my vision was in the shop completely wrecked due to 'battery communication error' on the other battery and I did not know how to discharge the fully charged battery without a phantom). That battery visibly 'puffed'. My bad - I abused that particular battery.
Q1: The other battery was maintained as per DJI specs, not left charged more than four or five days, and not exposed to cold temperatures...but I often flew it down to around 20%. On that particular battery, I did the 8% every 20 cycles (per DJI), but would spin the props all the way to 8%. I now understand that I should just turn the battery on without load and let it drain slowly down to 8% - right?
What killed it - 20% flight times, or 8% spinning?
Q2: The last three (all square contacts, bought within 2 months of the first two crapping out) - I have done everything per the seeming consensus of the forums. I land between 25% and 35%. Still do the 8% (lot of conflicting opinions on this - I know) every 20 cycles - but do it without load. When I know they will be stored for more than 5 days, I store somewhere around 60% charged. Why is #3 giving me problems this early in its 300 cycle lifespan...
q2a: I accidentally left two of the three in the truck fully charged overnight when the temp got down to mid 20's last winter. I know that's bad - but is it a battery killer? and if so - it took months before I saw the problem and so far its only in the one battery?
q2b: I fly in South Carolina where this summer has been hellish. Is flying when temps are over 100F bad for the battery?
Q3: Aftermarket batteries - eh? 12 month warranty. I don't want to - but the 'abusing my battery' remark from DJI kind of ticked me off. Limefuel - looking pretty good to me....if anybody has crash caused by a Limefuel battery not communicating during flight - please let me know?
I had that with a DJI battery and do not want to see the 100ft. plummet to earth again.
In case it matters - I fly at least three to five batteries a week. Mostly in the heat and humidity but still probably two a week in the winters. I don't typically 'fly hard', but rarely do push it full throttle. I don't carry any kind of additional payload. Flying a phantom vision and a vision plus at present, mostly the plus - although the autolands happen on both machines. No puffing noticeable on four of the five batteries I own.
Lastly (long post) - I've read the forums and everybody has an opinion. I understand opinions, but I'm looking for some kind of lithium chemo-physics genius to tell me what I'm doing wrong. I'm not trashing DJI batteries - I just can't figure out what I'm doing wrong.