Hi all, I have seen a number of posts re the issue of Inspire 1 batteries dropping from good power to zero in seconds. I have always been sceptical but today I learned the lesson - this is happening. I had to do a demo flight for a potential client today. I had not flown the I1 since September 19th when I filmed a charity swim - after which I charged my batteries to 100% as normal. I have seen some pretty eratic behaviour with my Phantom 2 Vision Plus batteries where they read three greens on take-off but deplete more rapidly than the apparent charge level suggests they should. So I have a policy of ALWAYS charging batteries which have been unused for more than a few days. On this occassion I failed to do this with the Inspire 1 batteries as I had been ill for the few days before and, quite honestly, failed to notice it had been so long since I flew. All three batteries were showing 3 greens out of four and when I loaded battery 1 it showed 60%. I was only planning a short trip accross a flat, empty park so I felt confident that the 8 minutes showing as my remaining flight time was more than enough - plus I had two additional batteries. On take-off all was fine until I reached a height of about 50m ( on the video I wrongly say 30m, but watch the sensor data) and a distance of 67m. The battery has dropped from 60% to 54% in 1.04 minutes. This seemed about right for the remaining time. However two seconds later the power drops instantly to 2% then 1% and an autoland initiates. Fortunately I retained control of the Inspire and brought it closer before it lost all its height and I stopped it in mid air at 1M - after which it landed safely and shut down. Since I had a client with me I felt I had no choice but to try again with battery 2. So take off number 2 was initiated. This battery showed 63% and flew flawlessly for the full five minutes of flight and landed back with 40%. I didn't need to use battery 3 so I have no data on that. Whilst I accept completely one should always fly with 100% power it should be completely safe to go with 60% - albeit with a greatly reduced flight time. It is clearly not acceptable that a battery drops from over 50% to 1% in a couple of seconds. DJI, can you please tell me if this is a known issue and if there is a fix in the pipeline? The I1 and all batteries are using the latest Firmware (1.4.0.10). Here is the video of the data during the flight. Cheers, Eddie.
The problem is - I see 10x % in your posting but 0x voltage. Your video also shows only % so can say nothing as this value cannot be trusted.
Only 2 rules to prevent surprises:
1. Forget %
2. Only look for voltage
Maybe you can check how much voltage your battery really had:
1. Upload your logs to www.healthydrones.com
2. Go to Power ---> Battery cells (if you had a major deviation you will see real voltage the battery had)
When I started with a battery at 60% which fell to 1% after 2 minutes I realized it started with about 3,5v which is much to low for "60%" so no surprise it reachead almost 3.3v = 0 after 2 minutes.
Battery shown 60% but in reality had this voltage:
Flight Time
Deviation
Cell 1
Cell 2
Cell 3
Cell 4
Cell 5
Cell 6
00m 15s
0.142v
3.501v
3.501v
3.535v
3.494v
3.544v
3.352v
You see where is the problem. I did not happen a surprise failure it just shows fictious % values. The battery actually was at 10-15% but showed 60%.
known issue when flying a battery that has self discharged without first charging it, however i thought they said they fixed it in new firmware. apparently not.
The fix is to charge it to 100% and then fly your inspire till if forces you to land at 10% or 5% or whatever, I highly recommend low careful flying or hovering a foot or so from the ground just in case of repeat incident which is very likely but may not occur if their fix kinda works, and then let it sit on the ground till it powers itself off, let battery cool, then fully recharge it and it should be back to reading accurate and shouldnt sudden drop unless it self discharges and you fly without charging it first again. Ive set my self discharge time to 10 days to lessen the likelihood of this issue happening to me, and never fly a self discharged battery without first charging it, and even still fly it carefully just to be sure. Ive only had this issue happen twice but i fly pretty regular and dont often let my batteries self discharge.
@ edward.allison - What I have noticed is that if you take flight without the battery being at 100% your charge will plumage down to nothing within no time. I did 60% not long ago and had the same issue. I learned to charge 100% then flight. I have never had an issue since. Safe flying wish I could be of better help to you.
Thanks for all the help and advice on this topic. I have learned a bit about voltage v % and also a timely reminder NEVER to fly with less than 100% (which I knew but allowed myself the fatal mistaken thought of "it'll be ok just this once as I only have 10 minutes demo to do" - WRONG). I see the latest from ware out today for the I1 (1.50.30) states it resolves this problem. I am hoping that is correct! safe flying to all.
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