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Battery drop from 56% to 5% in 10s

Discussion in 'Inspire 1 Discussion' started by Sciro16V, Aug 21, 2015.

  1. Sciro16V

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    Hi everyone. Today i had first issue with my inspire. About 200+ flights done smooth but yesterday and some days ago i was flying above big lakes in my country and all was ok. I was charging in harbour places because no power on boat. I have flight that used my battery to 56% yesterday. Today i had started very early to make some sunrise. Calibration ok check list ok so up. And sudenly power monitor on right side goes red and after fev seconds critical battery alert. I was not long and not so high so quick landing was sucessfull but on the edge 0% battery. I was first time charging both controller and battery at same time because of no time in harbour. Could this be na issue? Or battery is not right? It says 92% life. Discharged full cycle when needed. Used not fully charge before and no issue. Should i get it back to DJI?

    Im on latest firmware.
     
    #1 Sciro16V, Aug 21, 2015
    Last edited: Aug 21, 2015
  2. Scotflieger

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    Hi Sciro
    This is the well documented (in this forum) of battery sudden death where the battery falls off the cliff (a known LiPo feature). It is strongly recommended that you only fly with fully charged.

    What firmware are you using? Had you updated this battery to the latest firmware (1.3.0.0)? Have you carried out the DJI recommended 100%-5% continuous discharge recalibration (also documented here)?
     
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  3. JohnHan

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    It is common belief around here to only start a flight with a battery that is 100% and has recently come off the charger. My definition of recently is 2 or 3 days. For the reasons that you experienced first hand. I have done my own experiments (indoors not risking the craft) and am a true believer in this common belief. That is 1. 100% and 2. Just off the charger = best results, longest flight times.
     
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  4. Sciro16V

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    Yes i have latest software and battery upgrade. And yes i did 100-5% discharge before i went off on this journey. I have to use my batteries whole time and i cannot charge them on boat so some times i have to fly battery drained from before day flights. I was useing not fully charged before and there was zero problems since yesterday morning.
     
  5. Sciro16V

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    After last firmware update i saw some strange log entries. I will put them asap. I saw a post somwhere that kind of messages could be posible due to new battery life algorithm. I will check tommorow log before flight and see is everything alright now. I have some flights to do. I wish that all be ok.
     
  6. johnmont250

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    Yes, only fly fully charged batteries. Simple way to avoid disaster. It's well documented. Buy more batteries.
     
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  7. Meijs

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    Fully charged battery, landed for a short stop, went up again with 50% bat. went out over a glacier, got a battery drop from 42% to 6% in the blink of an eye, combined with the "compass error" the Inspire went havoc spinning out of control, crashed and sank to the bottom fo the Greenland sea. Two hours of boat trip, a film job and my Inspire was wasted...
     
  8. SultanGris

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    What is your battery self discharge time set to? I've flown partial batteries 20+ times, sometimes a few hours after the first use and sometimes a couple days later and I've only had the sudden drop issue 2 times, both of which were on batteries that had self discharged. While flying partial batteries that were 100 and flown down to whatever and flown again later I've never had an issue.

    When I realized the issue happened only with batteries that had self discharged I changed the time to the max of 10 days and haven't had a problem since. I thought the last couple firmware versions were supposed to fix this problem though.
     
  9. ovisopa

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    So it happens even after a short stop? I though this issue can appear when batteries are left a few days and then flown again half discharged.

    I'm so curious to know more about this as with my current hexacopter, I never had issues like this with nanotech lipos and the blue zippys, some of my jobs do require this kind of workflow: drive to a village, make a few pictures in the center than move to another one .. and so on. I almost never needed to fly more than 5 minutes, and with my lipo's I used them on 2 locations, than charged in the car to full.

    With the inspire I'm risking doing the same ?

    I didn't received my Inspire yet (can't believe the package didn't reached to DHL even if I received the tracking code on 9th september) and don;t know what this is, but it sounds as a setting for the batteries, they do have something like this, what is the minimum and maximum you can set ? Where do you setup this , in the DJI GO app ?

    thank you.
     
  10. SultanGris

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    yes this will only happen on the inspire "smart" batteries, you wont have this issue with any other lipo battery. its a setting in the app you get to by having the battery in the inspire turned on and connected to the RC so you can see the live feed video, at the top of the app there will be a battery power percentage display, click that and it opens a window that shows individual cell voltage, times charged and overall battery health/life and so on.

    You can set the self discharge for anywhere from 1 day to 10 days on this screen, and when that amount of time occurs if the battery is left fully charged and unattended it will discharge itself down to like 50-60% to prevent damage that can occur from storing fully charged lipo batteries. Apparently they swell up and explode or something.

    Some people think that using only part of a fully charged battery and then going back later and using the rest of it is the cause of this issue but like i said i do it all the time and have no problems with my self discharge set to the max of 10 days and always having used them within this time. By default this self discharge time is set much lower than the 10 day max, i forget exactly, and im nearly certain that it is the cause of this problem based on my experiences.

    This is pure speculation here as to why i think this happens since no one ever answers the question as to what self discharge time they have set when i ask in these type of threads but im guessing the people with the issues are using batteries set to a day or so self discharge. im guessing that the time starts counting down from time fully charged and doesnt disable until the power reaches the target discharge rate of 50-60% or whatever it is so for example if you charge a battery and wait a day or two and fly it down to 80% and wait another day or two before flying it again it still triggers the self discharge cycle cause it thinks its still 100% and when it gets lower after some use on the second flight it says hey wait a minute, I dont have as much power left as i should, lets adjust that %50 left to 6% or whatever.

    These are so called smart batteries and im quite certain they do not display actual battery power left but rather the amount that can be used without causing permanent damage based on cell voltage levels and as such 0% power reported isnt really 0% power available. The manual states that you should drain the batteries from 100% till they shut themselves off every 10 charge cycles to reset them and maintain optimal battery health. Some people freak out about this cause draining normal lipo batteries to 0 is very very bad for them and im guessing many people with these issues arent performing this reset procedure which could also be a factor in causing the sudden drop issue.

    It makes no sense that they would recommend something harmful in the user manual so its only logical that my theory here is correct, they have faulty firmware/code/algorithms which get out of wack and report incorrectly, especially when the self discharge feature activates. Thats why the power levels sometimes suddenly drop drastically. The drain till powers itself off procedure resets it and makes it more accurate. Im nearly certain of this cause the 2 batteries i had the sudden drop problem that self discharged sat at 0% for 30 minutes or more before they powered off when doing this and the batteries with no issues shut off at 3% or shortly after hitting 0% consistently.

    Now with that being said i should also note that this occurred on older firmware versions and supposedly they corrected the problem in one of the last two newest versions, however dji isnt known for their ability to fix problems very effectively and nearly every new version so far has introduced new problems/bugs. I cant test it because im still running older firmware and have no intention of updating to current for various reasons. Its hard to say for sure if the OP updated the firmware and performed the battery reset procedures correctly or if this problem still exists despite their attempted fix or if his problem is due to a new bug in the latest version or if his battery is getting weak if its older and been charged 100 times or whatever. However there is no logical reason why you shouldnt be able to use part of a healthy battery and then use the rest of it the same or next couple days without problems.
     
  11. ovisopa

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    Thank's for the detailed reply, I'm pretty sure that an intelligent DJI lipo drained to 0% it's drained to a safe voltage, I believe this could be easily measured with a multimeter so we know what DJI thinks it's safe for their LIPOs.

    What I'm very curious but hope I will never have the occasion, is what is the voltage of a DJI lipo that turned from 50% to 5% in a blink of an eye.
     
  12. SultanGris

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    i have no idea as that info is displayed in another screen and i never looked because i was trying to land quickly before it crashed, in my case it went from around 36% to 7% once and i forget the numbers from the other time but they were slightly different. This guy says 56 to near 0, ive seen people say 80 to 5 and even some say it dropped from whatever to shutting off and crashing instantly. i would think it depends on how much you used the first flight and how long it was in self discharge mode for until you used it again.
     
  13. Rileylaker

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    I'd like to chime in on this thread as I have had the same issue. Purchased my Inspire 5 months and love it. Have had 250+ successful flights and never a crash as I've been flying RC for years. I fly A LOT over open water and I had a scare in August where my battery went from 35 down to 4 in the blink of an eye, then went critical and started descending. Thankfully I had enough height for a successful glide back to the dock. Last week however, it happened again and I was not so lucky. The Inspire went to the bottom of the lake. I retrieved it but of course it's DOA. Have sent the story, video and recorded flight logs in to DJI for warranty claim and now I'm playing the waiting game.

    Seeing as we have all had this issue as well, has anyone been successful in making a warranty claim as a result of this power dropping issue? I have several batteries, numbered for proper cycling, all firmware was up to date so I chalked the first one up as an anomaly but this 2nd time has killed my drone and my business. Anyone successful with a claim?
     
  14. Scotflieger

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    @Rileylaker sorry to hear of your loss. With everything at the latest firmware had you recalibrated your batteries after FW 1.3.0.0? The recommended continuous 100-5% discharge should have overcome the sudden battery cliff drop off you experienced. Was the battery in use fully recharged immediately prior to the last flight?

    If the answer to the above questions is yes and you have an accurate record of your battery usage then you might be able to claim against DJI. Contact them and see.

    You say your business will be affected so I assume you are insured against such loses.
     
  15. Rileylaker

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    @Scotflieger thanks for the reply. I always fully charge batteries and in that case, the battery in question was used the night before, fully charged, then the next morning the incident happened. Went through the 100-5% cycle just a few days prior. Not the first incident with this aircraft. My other TB47 battery has done the same thing. I only buy TB48's now because the 47's are crap anyway IMHO. I'm in communication with DJI already but was just curious is anybody else who has had this problem has been successful with a warranty claim? I am fully insured but my deductible is set high for lower premiums because there are only a few underwriters in Canada at the moment and their fees are ridiculous. Will pull that trigger if I have to but want to fully exhaust this option first. How are the insurance rates in the UK? Cheers!
     
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  16. Steve Reid

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    Yes I had the same problem and crashed, sent my I1 back but they told me not to send the battery after telling them it was the battery that cause it. they gave me a new bird after 3 months and it crashed from the same battery. I called them to see if i could exchange it here and they told me I had to send it back. I told them to stick it, I wasn't going to wait 3 month to see it I got a replacement. Plus they told me I may have to pay them after they checked it. So I just ordered a new one from Amazon where I can send it back. No damage on the hard landing in the second crash, I was about 10 feet off the ground. Just do what you have to do, they have you over a barrel now.
     
  17. Scotflieger

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    There are very few insurance companies in the UK prepared to cover RPAs and operators. From my experience, cover is only available for those starting down the formal CAA approval route and premiums are high. I am with Coverdrone.
     
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  18. Grant Skelton

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    Had exactly the same issue with a brand new battery yesterday. Purchased from Amazon UK. I received it and fully charged it. Took off and everything was fine, showing 100%. Flew about 80m away and about 150ft high. Suddenly dropped to 4% critical. Managed to land in a field and retrieve the Inspire 1. Called Amazon they were very good, dispatched a new Battery that should arrive today and a shipping label to send old one Back. I'm insured but it still scared the crap out of me, first year insurance excess is very high!!!!
     
  19. The Editor

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    This does sound like a faulty pack.
    This is why I always regularly check how the cells are tracking during each flight. I usually pop into the battery info screen to take a look at the individual cell levels maybe two or three times each flight. It only takes probably 5 seconds to do. I just pop the Inspire in hover and flick over to the screen. If any cell is dramatically out of whack with the others alarm bells start ringing in my head and I bring the aircraft home to land.
    I also do not fully trust a new pack until I have around half a dozen flights on it.
    It's just me being totally risk adverse and Captain Cautious.
     
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  20. Grant Skelton

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    Great advice... lesson learned!