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Warning! Always check your battery cell levels before flight!

Discussion in 'News' started by Kirk Pleasant, Apr 12, 2015.

  1. Kirk Pleasant

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    Flying yesterday with a TB48 I had an unexpected "Critical Low Battery" warning.
    I was lucky because I was practicing ATTI flying in fairly strong winds in a flat open area.
    If I had been out over water I would have surely lost the Inspire 1.
    The battery was charged to 100% before the flight. The battery dropped from 52% to 8% in 1 second and I maneuvered the Insipre to a safe landing spot 16 seconds later landing with 4% battery.
    I checked the cell levels after landing and found one cell was .32v less than the others.
    When I recharged the battery that cell remained low and it has only charged to 57% before the over voltage protection kicks in.
    I live in the Middle East and there is no DJI dealer in the country that I live. I bought the battery in Singapore and I am not sure when the next time I will be traveling there to be able to replace it.
    Things that I have learned from this-
    - Always check cell levels when changing batteries (also if in flight and going over water, un-recoverable terrain or people)
    - Make sure the volume is on max for my IPad so I know instantly why the Inspire 1 is starting to go into landing mode unexpectedly!

    Cheers

    image.jpg image.jpg image.jpg image.jpg image.jpg
     
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  2. lrwskyfilms

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    Thx for sharing, glad you landed safely.
     
  3. The Editor

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    How many cycles were on that pack?
    Had it been calibrated recently?
    I ALWAYS advise going into the battery screen a couple of times during flight to visually check cell levels in relation to each other.
    Glad you saved your Inspire.
     
    John Archer likes this.
  4. Kirk Pleasant

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    Hi,

    There were less than 15 cycles on the packs.
    I calibrated the battery when I 1st got it.
    I will be checking it multiple times during flight now!

    I am really starting to lose confidence in this machine. There have been many times in the 13 hrs I have flown it that if this had happen, the out come could have been very bad.
     
  5. Harry Nicholson

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    Surely DJI would honour warranty if the Inspire had of crashed because of this?
     
  6. Harry Nicholson

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    Whats the 100% best way to calibrate the battery?
    Theres seems so many conflicting ways to do this, any guidance greatly appreciated as Im doing a flight tomorrow and will be testing my Inspire a little more than normal

    Kind Regards
     
  7. sirnikolas

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    +1!
     
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  8. Harry Nicholson

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    Guidance from a senior pilot?
     
  9. sirnikolas

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    Fully discharge the battery and make sure you see 0% Then recharge.
    This process can sometimes rejuvenate bad cells.
    If not, contact DJI.
    DJI recommend discharging your batteries every 20 cycles or when the battery reads abnormal voltages as like the post above ^^
     
    #9 sirnikolas, Apr 12, 2015
    Last edited: Apr 12, 2015
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  10. The Editor

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    Yup - as above.
    This is the recommended way to discharge and calibrate your packs. The manual gives the slow version (put it in the Inspire, switch on and wait..
    Or the faster version, fly until you can no longer sustain lift and/or the battery shuts down).

    Allow the pack to cool and recover back up to ambient temp (usually around 30 mins or so) then charge FULLY.

    You are then set for another 20 cycles.

    The 20 cycle number is not a hard and fast rule.... you could do it at 15 or even 25,26,27 etc as long as you DO DO IT periodically and at fairly regular intervals.
     
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  11. 1vertol

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    That thing is stupid fast! Damn...
     
  12. DCGOO

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    Actually the manual for the Inspire suggests doing this after every 10 cycles.

    Quote:
    How to discharge your Intelligent Flight Battery:

    To effectively calibrate the battery capacity, it is recommended to charge and discharge the battery thoroughly for every 10 charge-and-discharge cycle. User should install the battery onto the aircraft and then power on the aircraft to initiate the discharge process, discharge the battery until the aircraft is powered off automatically. User should then fully charge the battery to ensure the battery is working at its optimal.

    Slow: Place the Intelligent Flight Battery into the Inspire 1’s Battery Compartment and power it on. Leave it on until there is less than 5% of power left, or until the battery can no longer be turned on. Launch the DJI Pilot app to check battery level.

    Rapid: Fly the Inspire 1 outdoors until there is less than 5% of power left, or until the battery can no longer be turned on.

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  13. The Editor

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    There is actually contradicting information across various version of both the manual and the intelligent flight battery instructions. Every 20 cycles is far more realistic than the overly cautious 10.

    It is a moot point in any case since then next firmware version will inform you when to do a calibration and/or when one is needed.
     
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  14. sirnikolas

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    The info I posted was straight from the horses mouth (DJI tech support)
     
  15. lrwskyfilms

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    Great idea, though I hope this FW happens soon, it is suppose to fix so many issues, if it doesn't people are going to get even more p'off, only got my batteries last week, which were paid for in January.
     
  16. The Editor

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    That's why I ended up getting all my TB48's from FleaBay. ;)
     
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  17. lrwskyfilms

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    Yes likewise I had to get 2 on fleabay early on. :) Just feel the UK and many other countries outside the US are poorly supported. Just saying.
     
  18. Erik vonBartheld

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    This happened to me a few times on my Vision+. One way that might work if you're in critical battery is to fly the quad horizontally. The first time this happened, I was demo-ing for a few guys who were on the pier I was on fishing. I took it over the water to let them see and realized the Phantom was sinking and not responding to vertical thrust. Now it's lower than the railing of the pier, so I punched it toward the beach, hoping to at least make it onto sand. As the Phantom picked up speed toward the beach, I noticed it allowed me to get lift as well so I gave it thrust up and to the right and quickly landed it on the pier about 1000 feet away... luckily it was very early morning and nobody there to be in danger - but it saved my phantom.

    I also noticed this with a brand new P2V+ (new battery) - again over the ocean. Battery started out 100% and quickly turned to critical with the Phantom wanting to become a submarine. As soon as I realized what was happening I again remembered to use the battery power to fly horizontally as quick as I could towards shore - it made it - landing in dry sand, but at least it didn't become a dolphin chew toy.

    I have not needed to do this (yet) with Inspire, but in a jam, it may do the trick. Thanks for this good advice.
     
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  19. tuxtopia

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    Thanks for sharing that. I had something very similar when flying my i1 in Iceland. I was about 200m out to sea and all of a sudden the battery level dropped from nearly fully charged to less than 25%. Reaction time was everything and I managed to get it to dry land and land it safely. I could have produced a diamond if you catch my drift!.

    The battery level drop can be clearly seen in the flight log and when viewing the battery (TB47) stats in the GO app, cell 3 sometimes shows 2.6v where as the other five show 3.81v. Total charges for that particular battery is 12, battery life is at 97%. I have eight TB47's and each are labelled as BAT1,2,3,4 etc. I have since discharged the one battery and cleaned all contacts with alcohol and so far, all cells are reporting 3.81v.

    However, I think a cell check and not just a level check is an essential part of a checklist before takeoff.

    Thanks again.