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looking for opinions on the following:

Discussion in 'Inspire 1 Discussion' started by m00se, May 16, 2015.

  1. m00se

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    im looking for constructive comments and opinions on the following :

    Everything about the I1 is overheating in the environment in which I live. During flights last week, I looked at the battery screen, and it was on 75 degrees after just 7 mins of flight....
    question 1) do people think I should limit the flight time to avoid cooking batteries? I know that LIPOS are generally specced at <60C. I also have seen that DJI use metal plates inside the battery between cells to bring the heat out and somewhat help with inflight cooling . (an excelent idea)

    2) what do people generally think about making an active cooler in order to being the batteries back to safe charging temp quicker and allow me to recharge them in a reasonable time between flights.

    the current situation is that the batteries, when kept at ambient temp (40c) take around 45 - 60 mins to cool. I have three chargers, meaning that I cant put the batteries on charge for ages after flights, thus losing charging time and meaning I need more batteries to fly almost continuously.

    My ipad also overheated on the last gig, and blacked out, luckily i was landing......

    My plan is the following:

    revise my charging case I made, and make some 3d printed parts that hold the batteries in place a bit better, and also have a temp sensor and air ducts in them.
    the temp sensor will, if the battery if over a certain temp ( to be determined) turn on a peltier device and a fan on the cool side of it, the air will be channeled to the battery, until the temp comes down to charging specs. then turn off the cooler and leave it charging as normal.

    I have 2 12v fans ont eh case to keep the power supplies cool, and that works well,
    it was when I was in an airconditioned room recharging the batteries that I realised they had started to recharge in a much quicker time.

    Sorry for the long post
     
  2. DCGOO

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    In what environment do you Iive/fly? Mine usually end up only slightly warm to the touch. Nothing anywhere near 70c.
     
  3. m00se

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    I basically live in a desert, where 50c ambient is possible, 45 is now a daily occurance for the next 5 months....
     
  4. DCGOO

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    Hmmm... The Inspire is only spec'd to operate within -10 to +40c. Going to be hard to stay cool if ambient is +45.
     
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  5. m00se

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    haha i didnt know that. That would rule out basically 50% of the year here.........
    I guess the ESC and lightbridge might be getting hot too in that case.

    Maybe a heatsink that clips onto the battery once in the craft would be doable......
     
  6. damoncooper

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    Yeah I agree you may need to get creative. I'm sure others would be interested to know what you come up with.

    One idea that comes to mind is a portable powered beer cooler. Pop the batteries in there to accelerate cooling.

    As a bonus, after flying, you can have a cold one. :)
     
    #6 damoncooper, May 16, 2015
    Last edited: May 16, 2015
  7. m00se

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    ive looked at the 12v mini fridges. and most of them just use a peltier device, so i think I can recreate the cooling effect for about 15 usd, and build it into my current charging setup.......

    It seems that maybe the cooling of the I1 could be a more worrysome problem though
     
  8. Mike Gravo

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    Wow. I don't know how you do it. I would spend the next five months inside with the air conditioning on. Those are ridiculous daily temps!
     
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  9. m00se

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    haha, most people do, but when your job is to fly cuads,,,,, then you have to ocassionally man up
     
  10. dmelle

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    I'm gonna keep an eye on this.. I live in Dallas, and we sit close to that temp for a few months out of the year ;)
     
  11. m00se

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  12. dmelle

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    What do you think about rigging something up to an a/c vent in your car/truck... Would be wasteful as far as gas, but that could blow some nice cold air... Maybe be a silly idea, but I had to post when it popped into my mind...
     
  13. Scotflieger

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    First I would never volunteerily live in such hot condition. Above 20C and I start melting.

    Seriously, have you tied pre-cooling the batteries. If you can start with them at <20C from an ice box then that will give you some latitude. Also the DJI operating range is there for a reason. One of the reasons for the higher battery temperatures is that they will be operating harder due to the high ambient temperature. The air will be less dense and more power will be needed just to lift the I1. Look up Density Altitude on Wikipedia. This is why Edwards Air Force Base in the Mojave Desert do all their test flying at dawn before the temperature climbs.

    Finally, if you allow your batteries to overheat it could be catastrophic if they ignite either spontaneously or if you have a heavy landing. You will lose your Inspire. Similarly, DO NOT try to recharge your batteries until you have allowed them to cool fully to ambient temperature or better still to sub 20C.

    I think you will be flying in the early morning for the next few months.
     
  14. m00se

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    I had thought about putting the charging case inside the car and leaving the AC on, but you cant always be with your car when flying, hence thinking of a way to cool it in the field, even if admittedly a power source is needed, but hey thats needed to recharge anyway, so shouldnt be a problem.
     
  15. m00se

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    never say never, some places have pretty good salaries :)


    that would be catastrophic, Lipos that are below about 10c have a huge voltage sag, and do not perform as expected.

    interesting, I was flying with around an additional 800g on the inspire also, I knew that would stress it a little more than normal, but it handeld it well in the testing.


    from what ive seen online, it takes a fair bit more than 70 degrees to ignite a lipo from temp alone
     
  16. Kilrah

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    Except that isn't a thing in that location... :( I live in the same place as OP and that's one of the things I miss most :p

    Just do what 80% of people do and dash away to more reasonable places during that half year... I^m leaving next week myself ;)

    He said 20°C, not freezing. Indeed starting with the pack at 20° would be a good idea.

    Depends on the actual battery chemistry type. Some can hold up to 130°C or so, but some will go off as low as 70° indeed. No idea what's used in the Inspire.
     
  17. m00se

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    im having a shitty day, for some reason "<20" translated as "-20" in my retarded head today. lol

    So maybe a coolbox to stuff the in before flight? I wonder about condesation?
     
  18. DCGOO

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    I really doubt the battery itself is particularly concerning. I would interpret that spec as overall environment for operating the aircraft. I would expect the battery itself could/should get much warmer, I don't think DJI routinely quotes the temp limits on the battery. Kind of like the CPU in my laptop right now (idling along) reads 50.6c. But that is actually quite cool.

    You should contact DJI and ask them if they have any advice for operating in temps above 40c. Be prepared for that advice to be "don't do it." That +40 number appears across their entire product line. But I really have no idea how tight that spec actually is. It very rarely gets above 32 in my location, and is 21c right now.
     
  19. m00se

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    i think the manual says the battery is good up to 60 degrees. Hmmmm.....

    I will have little choice but to continue using it. I will try to keep flights early and later in the day, and avoid the hottest part of the day,

    meanwhile I might just hunt a mini fridge and test it out. then rip the guys out and put them in my charging case
     
  20. damoncooper

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    Found this about lipos in general (older RC Groups post but likely still relevant):

    Bottom line I think: try to cool them down before recharging and stick to morning / evening flights if possible if you have to operate in that kind of heat.

    ImageUploadedByTapatalk1431869482.062669.jpg