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Standard charger causing possible problems with batteries?

Discussion in 'Inspire 1 Help' started by apsussex, Jun 15, 2015.

  1. apsussex

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    OK this is the first time something like this has happened, basically did a couple of flights tonight, everything perfect as normal, landed the TB48 at 31% and TB47 at 28%, both battery voltages equal in all cells.

    Come back home later to charge up the batteries, and always out of habbit check the power on the battery and both batteries showed led 1 lit with second flashing, as soon as I put the TB48 into the charger and switched on to charge, it started flashing just the led1, and continued to do this for quite a while. Seemed a little strange, so I swapped to the TB47 and a quick check before, led 1 lit and second flashing, as soon as its switched on with the charger, exactly the same as the TB48, flashing led1, so I immediately thought I would check this within the inspire, and its showing 2% critical battery with all cell voltages at 3.77 then dropped to 1%. Even shows the 1 flashing LED on the battery power check too.

    This is very wierd and obviously triggered from the charger somehow. How could the charger suddenly cause them to read a loss of 26% battery power? If this happened with just hte one battery then I would have questioned the battery itself, but to happen to both batteries definately seems to point towards the charger.

    Anyone ever had this before. I just have the standard charger, latest firmware installed, have already flown without any issues with the latest update as well. Totaly baffled to why this happened.

    Any thoughts would be great

    Thank you
    Sam
     
  2. Carlsberg

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    No Sam.
    If you are referring to the 100w "power supply" that comes with the I1, then NO, it is not the cause of any of your problems. The power supply does nothing but supply the pack with up to 108w when asked of it.

    Any problems you may be having involve the lipo pack's circuit board, or it's firmware.
    Hope this helps. :)
     
  3. The Editor

    The Editor Moderator
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    It's nothing to worry about and your batteries haven't suddenly dropped to 2% or anything.
    By putting your packs in the Inspire at circa 20% charge you experienced the dreaded "sudden percentage drop" scenario.
    The Inspire is expecting 100% fully charged battery when you fire it up. You put in a 20% (or thereabouts) battery and the Inspire did a quick calculation and then erroneously reported 2%.
    Fuel cell indicators based on voltage are notoriously unreliable and the Inspire is no exception. This is whybit is SO important to

    Always start your flights within fully charged pack.
    Always make sure you calibrate your packs regularly as DJI advise.
     
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  4. apsussex

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    Thanks for the reply chaps, I think what put up a red flag was that it did it to both batteries as soon as the charger was connected and I have always landed with a battery around 30%, but they both are charging fine now anyway.

    Yep I religiously only take a flight with the battery pack at 100% (I think also the battery log book shows its importance here too). Its the balancing process at the end of the charge I believe is the most important. Although ideally I would like to have a cell voltage checker that fits the inspire battery, as the one I have can only be used for brick type lipos. Certainly be happier doing it manually than using the DJI Pilot app.
     
  5. Hose A

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    While on the subject of batteries, I have a question: It appears that a new FW update is about to be released. I did not install the previous release (1.2.1.06) because many folks were having problems with their batteries after the update. I am still running 1.2.1.03. My question is that when and if I should install the next FW update, are my batteries going to update per 1.2.1.06 whether I want them to or not? Or ... do I have to install 1.2.1.06 before the next update can be installed?
     
  6. Carlsberg

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    Both of these statements are incorrect and there are zero "facts" to back it up.
    Spreading mis-information is a plague on the internet.

    The Inspire is NOT expecting a ("fully charged pack") every time the motors are energized.
    (there would be no need for battery telemetry then, u insert fully charged pack, start timer, fly for 15 minutes, like in the old days of 6 years ago).

    I fly Cell Tower inspections daily for a living, with Real Estate shoots sprinkled in when I have time, (that's right, I get right next to the high power transmitters including them round ones you fear so much) with never as much a twitch.

    I start with 100% charged pack, typically fly it down to about 70 - 75% during a thorough inspection, (60% if it's real windy or high 400ft tower). I then drive out to the new location, inspect another tower with the same pack, typically landing before the 30% warning I have set. I then remove the pack, then insert a fresh 100% pack and drive to the next location.
    On days I do Real Estate, I typically shoot 3 properties on a single pack.

    Let me please stress 2 facts about what I do when I get home,

    I always charge all packs fully the first chance I get.

    I plug a pack into a watt meter, then to the supply, so I can measure exactly how many mAh goes back into each pack.

    After updating bird, radio, packs to .2.1.0 (to get rid of the dreaded gps drop), I have no problems with anything, and the battery pack telemetry works perfectly.
    No way will I ever update these packs again since they are working perfect and are very predictable, (it was 2.1.3 that killed all these packs, mine pack still perfect on 2.1.0)


    Now lets address flying a 100% pack down to let's say about 50%, then letting it sit for a few days, then firing up the I1 with that pack and flying around.

    2 days ago I was giving the neighbors virtual tours with the Cinimizers.
    I had 4 packs ready and I was really tearing it up for them, (62 mph down wind), each person getting an exciting 5 miles flight, fast, slow, high, low.

    After landing and swapping packs, I strapped the 2nd neighbor and off we went.
    A minute later I was way far out there and very high, tearing it up, when I looked and noticed the pack was at 42%. Holy Crap Batman, I put in a used pack from last week !!!
    I should get back home NOW! (I cannot believe I could do something so stupid, not even look b4 take off).
    30% battery warning is flashing and i'm still a half mile out over a large Lake.
    I make it back home easily and land at my feet at 21%
    (always fly upwind at the start if you can, so your return flight is downwind - wink wink)


    6 Facts to take note of .........
    TB48 has 5700mAh when fully charged
    At 50% tb48 has 2850mAh left
    At 21% there will be 1197mAh left
    I should expect to put back 79%/4503mAh when I charge, (4514mAh actually went back in)
    mAh does NOT magically disappear over the course of a few days, (or a few weeks)
    I always charge all packs to 100% when I get home

    Do you guys know what the word "immediately" means?
    Now, every time I pull a pack from the I1, I "immediately" put a rubber band on it, indicating it is NOT a full pack.
    (I will never make that mistake again)

    Now I know your what your knee jerk reaction is going to be regarding me almost bumping cell towers hundreds of times to get high res close-ups, and also flying my packs around as if I know what is going with them.
    You're gonna wanna Post, and tell everyone that I'm just lucky, when in fact, YOU are the lucky one. "How is that" you say?
    I am flying around comfortably with actual knowledge of how lipo packs work, (with measurements and facts to back it), and you are flying around simply believing everything DJI tells you - (good grief).

    Please be reasonable here Editor, (or whoever you are, wink, wink)
    If every I1 owner MUST start every flight with a 100% pack, then the battery telemetry isn't worth jack chit now is it, (and should have NEVER been released).

    The FACT is, the battery telemetry WORKS PERFECTLY on 2.1.0 (did so before as well), They need to Stop messing it up with firmware updates, (and borrow a watt meter to gather FACTS).

    Please Stop spreading misinformation, the I1 does NOT need a full 5700mAh to take off and fly successfully, (that is purely crap started by DJI AFTER they TOLD everyone to drain their packs down to zero, killing hundreds of packs, during the 2.1.3 update).

    If your electric car manufacturer told you that you could NOT leave your house unless you had a full pack, you would laugh at them, and rightly so!


    3 things for peeps to take away from this post .....

    1) - get a watt meter and learn what is going on with your packs
    (they are cheap, and easy to use, even if you don't know how to solder)

    2) - understand that (under the plastic case and balance board) these are regular lipo cells and should not be discharged til the voltage drops below 3.1v and they fail.
    Rule of thumb has ALWAYS been try not to discharge past 80% rated capacity

    3) - this post is NOT a personal attack against The Editor, (or the other guys in his position on the other sites). They are only posting what DJI has TOLD them to post, (but how about asking them for some FACTS in the future, who cares what they SAY (ground station).

    There is NOTHING more important then your props and battery packs, keep a good eye on them.
     
    #6 Carlsberg, Jun 16, 2015
    Last edited: Jun 16, 2015
  7. The Editor

    The Editor Moderator
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    Well that told me then! What do I know anyway?
    Unfortunately (in my opinion) the algorithms/logic DJI use in their battery fuel gauge firmware is flawed. In fact most Lipo fuel gauge indicators based on voltage are not much good.

    As a Lipo ages it's internal resistance increases. This means it will not give up it's charge so readily when demand is put on the pack and also you will see a decrease in capacity of the pack. This is a fact of life and physics - you cannot escape it.

    Yes you can measure how much you put into a battery but this will change over time. A 5700 mah pack from new will not be a 5700mah after 50 or 60 cycles. Also, as the cells IR increases some power of the pack will be lost in heat and thermal dissipation. This has a direct affect on the amount of capacity you are able to draw from the pack as it ages.

    A lipo's discharge curve is non linear and has a fairly flat curve down to a certain voltage and then it will drop very quickly. Unfortunately, being flat it is notoriously difficult to accurately measure remaining pack capacity using voltage or potential difference under load.

    What you are doing (taking a fully charged pack, flying down to a certain level BUT NOT REMOVING THE PACK - then moving on and continue flying will work OK)
    However, try putting in a partially charged pack (say 60%), switch on and then take off and fly around and see what happens! You will get a percentage drop from 60% to critical level within a few mins (or in some case seconds). This is what I m talking about when I say 'The Inspire is expecting a fully charged pack'. Put a partially charged pack in and you are asking for problems.

    I would advise people to always start off with a full pack or it MAY come back and bite you in the backside.

    As an aside, DJI do not tell me to do anything. I do not work, nor have I ever worked nor am I affiliated to DJI or any of its subsidiaries. I am a free agent and give my advice based on my 30 years flying experience of everything R/C.

    I also keep a battery log (as well as a flight/maintenance log) and it forms an integral part of my ops manual lodged with the CAA. Keeping a battery log can show up 'trends' which may avert a failure not otherwise noticeable.


    Your Inspire - You fly it how you want.

    I know nothing ;)
     
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  8. DJeff1

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    Is this Bob?

     
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  9. The Editor

    The Editor Moderator
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    Mr Marley returns?????........
     
  10. Kilrah

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    Either him or another of those posters who have recently heavily insisted on spreading obviously wrong info/interpretations IMO...
     
  11. Carlsberg

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    This is also an incorrect statement.
    I spent a tremendous amount of time writing that post, and you clearly did not read the whole thing. I'm trying to teach you something here, and I am posting FACTS for all to read, (not opinions).

    Please READ this .......... again?


    I am going to repeat myself here .......

    mAh doesn't just magically disappear from a lipo pack, not in two days, not in 4 days, not in 7 days.
    If you use 2700mAh from your tb48, there will still be 3000mAh left, (it will NOT magically disappear, (regardless of what DJI says) ... Period!
     
    #11 Carlsberg, Jun 16, 2015
    Last edited: Jun 16, 2015
  12. Carlsberg

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    Please EXPLAIN yourself.
    What am I posting that is "wrong"?
    I just posted facts for you to read, please show me how I am wrong?

    If you're going to start an argument, will you please at least post your reasons for saying I'm wrong.
     
  13. apsussex

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    Carlsberg out of interest are you able to monitor all 6 cells via your voltage checker? or just the full voltage? I`m used to the balance cable from the Lipos used on the s900, but with the inspire battery, I have no idea how to adapt a voltage checker to read each of the 6 cells. What I have learned from my experience today is, I cant fully trust the battery pack LED or the Dji Pilot app voltage and percentage reading, and I need to find a voltage checker that will manually read each cell of the inspire battery (or just use one to display full voltage would do) and I can check this against the pilot app everytime I fly. There is obviously an issue with the firmware or circuitry because to suddenly drop its reading like that without being plugged into the inspire there really is no other explanation.
     
  14. Frank508

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    Thanks for that. I have been puzzling about this, and that explains it.
     
  15. The Editor

    The Editor Moderator
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    And you are quoting my post out of context and picking and choosing what you are arguing about.

    I am not saying that mah magically disappear. I am saying that if you put a partially charged pack into the Inspire and fire it up and fly it, the logic that interprets the remaining capacity in the pack will erroneously give an indication that it has dropped suddenly to critical levels. The Inspire will then auto land itself thinking the pack is down to 10% or so.
     
  16. Outta Control

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    [​IMG]

    If it is then this is his solution:
    [​IMG]
     
  17. Kilrah

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    No, but DJI's measurement will sometimes mess up its counting of them, and cause trouble.
    Experience from reports seems to indicate that when it screws up the battery was in most cases not fully charged, hence the warning and recommendation. That's it.

    If there had been as many people reporting the battery drop issue with a fully charged battery than with a partially charged one nobody would make that recommendation.

    The theory is pretty much useless there and can be mostly ignored, it's the behavior that is observed that counts.