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smart battery too smart?
643 8 2017-1-2
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punkie
lvl.4
Australia
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just having a little bitch here.. flying today I used half a battery and powered off the aircraft. After a few minutes I realised I needed to use it again but It wouldn't power on because (I assume) the battery was warm from the previous flight. Instead of booting up the battery LED did its 3 quick flashes which is it's high temp signal, am I correct? I'm not sure if this behaviour is normal, but I had to stand in the shadows and blow in between the cells for a few minutes until it cooled down enough for the battery to power on again, it's not like it was really hot, just midly warm. Fairly annoying as I still had about 59% on the battery, makes it difficult if you need to shoot small moments here and there, I can understand the safety constraints for charging at high temps, but this seems like safety overkill if it is such a limit on how a battery is used. Is it normal, would it be possible for a firmware change if this is the case?
2017-1-2
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Geebax
Captain
Australia
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The battery is trying to protect you from potential loss of your aircraft, I think you should be grateful for that. Also, flying again on a battery which is only 59% charged is also a recipe for disaster. There have been countless sad sack stories on here that began with 'I took off with a partially charged battery'. The LiPo batteries used in electric aircraft are a great innovation, but they have some rather nasty quirks, and charging a hot battery is a shortcut to a dead battery. I doubt that DJI would change their policy or firmware, as it it in line with best practice for LiPo batteries.

2017-1-2
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punkie
lvl.4
Australia
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Geebax Posted at 2017-1-2 03:00
The battery is trying to protect you from potential loss of your aircraft, I think you should be grateful for that. Also, flying again on a battery which is only 59% charged is also a recipe for disaster. There have been countless sad sack stories on here that began with 'I took off with a partially charged battery'. The LiPo batteries used in electric aircraft are a great innovation, but they have some rather nasty quirks, and charging a hot battery is a shortcut to a dead battery. I doubt that DJI would change their policy or firmware, as it it in line with best practice for LiPo batteries.

I totally understand about not charging a hot battery, for safety reasons and protection of the battery. however if I cannot switch the aircraft off for a few moments in between flights so that it's components do not heat up and shorten battery time over a shoot because it will not start up again due to a slightly warm battery (i.e. above ambient surrounding temperature) for me that is safety overkill and an inconvenience. I try not to use my batteries below 30%, I'm not out to wreck my batteries, aircraft or be reckless. It's just useful to be able to switch the aircraft off momentarily sometimes in between flights.
2017-1-2
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punkie
lvl.4
Australia
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funny thing is, I can't find any reference in the manual to the battery not being able to be switched on when temperature is above ambient air temp, so not even sure whether this is normal behaviour
2017-1-2
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marctronixx
Second Officer
Flight distance : 210118 ft
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United States
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Lithium is very unstable. Just look at the samsung galaxy phones exploding to give you an idea.

The battery has sensors in it that prevent you from using it if the internals are too hot. This is a safety feature by design to protect you and people around you.

If you think you will need to do this in the future, invest in a spare battery (or two) or pre plan your flights  for such last minute issues.
2017-1-2
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Hendo
lvl.3
Flight distance : 104495 ft
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New Zealand
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I would think your situation is rare. I've flown in hot temperatures (30 deg. C +) and never not been able to turn the battery back on, even after fast flying. As marctronixx says, invest in another battery, it will give the other one time to cool a little, which you should always do before you charge it anyway.
2017-1-2
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punkie
lvl.4
Australia
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thanks, I have two batteries, and another on its way, I've been flying rc helis and custom quads for years, so I do have some idea about looking after lipos. Ill do some testing on this to check for myself it's really happening. I was hoping a Dji rep might chime in so i can check that this is normal behaviour, I may have to query this with support as I haven't found an official answer on whether this is normal, It really wasn't what I would call hot for a battery, but it was on the morning of a very hot (high 30's) day, so ambient temp was reasonably high in the sun. Cant always plan everything that happens on a shoot, I had already used my first battery, and the opportunity just came up for another shot, when you're working outdoors flexibility is needed. yes i will be getting more batteries..
2017-1-2
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Phantomski
Captain
Flight distance : 12289669 ft
United States
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check the logs, make sure nothing funny is going on with the esc or one of the motors... u could try to check motor temps after landing... not sure.
Hottest battery was 150F, unfortunately cannot tell on which flight at the moment.... i do fly with a battery below even 50% sometimes, but it's pretty much an landing and takeoff, so it's still almost as hot as if i never stopped flying.. People r right though that taking off on a battery below 60% is questionable, especially if the battery is cold. Now, in your case you could look at battery temp in the logs, i think...  i use healthydriones account to syn my flight logs, gives some good into.. and then there's phantomhelp log viewer online, u can use to upload the log and have people look at it....
Hope u figure this out before u have a bigger problem, like a crash...
2017-1-2
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punkie
lvl.4
Australia
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Phantomski Posted at 2017-1-2 21:13
check the logs, make sure nothing funny is going on with the esc or one of the motors... u could try to check motor temps after landing... not sure.
Hottest battery was 150F, unfortunately cannot tell on which flight at the moment.... i do fly with a battery below even 50% sometimes, but it's pretty much an landing and takeoff, so it's still almost as hot as if i never stopped flying.. People r right though that taking off on a battery below 60% is questionable, especially if the battery is cold. Now, in your case you could look at battery temp in the logs, i think...  i use healthydriones account to syn my flight logs, gives some good into.. and then there's phantomhelp log viewer online, u can use to upload the log and have people look at it....
Hope u figure this out before u have a bigger problem, like a crash...

i'll look into checking my flight logs, it's a good idea..although i don't want them sitting on someone elses server, I'm new to dji flight logging and haven't learnt how to use it yet. the battery was barely above ambient environmental temperature...as far as I'm concerned the only problem with the temperature was that it prevented me from turning the battery on...I will look into the flight log when I can and check batt temp, however I really don't think their was any cause for concern over it's temperature. thank you for your suggestion
2017-1-2
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