Welcome to InspirePilots.com

Join the leading DJI Inspire community for free!

I Want My mah Back!

Discussion in 'Inspire 1 Discussion' started by damoncooper, Jan 23, 2016.

  1. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    I had 5700 when new! Now down to 5136! That's 564 missing mah!

    Where is my mah??

    ImageUploadedByTapatalk1453585558.585793.jpg
     
    Andy Lovell and IrishSights like this.
  2. filmscum

    Joined:
    Jan 4, 2016
    Messages:
    16
    Likes Received:
    1
    Location:
    Northern Wyoming
    Have you done a calibration? I'm still in my 10 cycle break in period (running to 50% then charging to 100%) and have noticed a slight decrease in mah that I'm hoping will return when I calibrate.
     
  3. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    Just finished deep cycle yes. Went to Power cutoff then full charge. This is the screen after topping back up and powering on.
     
  4. The Editor

    The Editor Moderator
    Staff Member

    Joined:
    Aug 7, 2013
    Messages:
    6,727
    Likes Received:
    3,881
    All lipos will loose their capacity over time. As the pack ages its internal resistance increases and its ability to convert chemical reaction to power diminishes. What the DJI calibration procedure does is to take into account the aging of the cells and calculates how over time the pack capacity reduces.
    They have written the algorithms to take into account not only times, charged/recharged but also to what level of depletion the pack has been drawn down to and generally how it has been treated.
    Having said that, their algorithms do seem a little 'over zealous' in how they go about calculating loss of capacity!
    Of course, this would have absolutely nothing to do with wanting to sell more batteries. :rolleyes:
     
    Ferdi, Phatzo, Kilrah and 1 other person like this.
  5. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA

    Over time I can understand but twelve flights?
     
  6. The Editor

    The Editor Moderator
    Staff Member

    Joined:
    Aug 7, 2013
    Messages:
    6,727
    Likes Received:
    3,881
    I know, that's why I said it can be over zealous.
    Has that pack been 'abused' more than others?
    I don't mean you have thrashed the hell out of it but has it been taken to low levels often or not stored at around 3.8v per cell or left for some time fully charged etc?
     
  7. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    Yeah a bit. It's my fairly new battery I modified when new. I fly it to 10% and try not to store it full but I have 2 day discharge on it
     
  8. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    What do you guys have left on your TB48's for capacity?
     
  9. The Editor

    The Editor Moderator
    Staff Member

    Joined:
    Aug 7, 2013
    Messages:
    6,727
    Likes Received:
    3,881
    That might be your answer then. :)
     
  10. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    I think losing 10% capacity in 12 flights is DJI's battery racket though. That's tough to swallow.
     
  11. The Editor

    The Editor Moderator
    Staff Member

    Joined:
    Aug 7, 2013
    Messages:
    6,727
    Likes Received:
    3,881
    I'm not disagreeing!
    I always try to make sure I fly my packs only to a point that when rested they recover back up to 3.7v per cell. This ensures they stay as healthy as possible.
    Assuming around a 0.2v rebound this equates to going no lower than 3.5v per cell under load (maybe 3.4 or just above).
    I agree though, some mAh disappearance is too rapid.
     
    damoncooper likes this.
  12. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    What do you have for remaining capacity on your TB48's? That may help me feel better :)
     
  13. The Editor

    The Editor Moderator
    Staff Member

    Joined:
    Aug 7, 2013
    Messages:
    6,727
    Likes Received:
    3,881
    LOL - I think my best is around 97% with around 20 something charges and around 91% with 40+ charges.
    That's from memory though - I'll confirm those figures when I can fire up the bird (it's past 11pm here so I won't do it now)
     
    damoncooper likes this.
  14. RaptorMan

    Joined:
    Dec 18, 2015
    Messages:
    770
    Likes Received:
    214
    Unless there 'over zealous' algorithm also artificially reduces actual flight time before reporting low battery it doesn't seem to me to make much difference -- the battery is going to have the capacity it has and you will get flight times accordingly. So, during flight, if your warning is set to, say, 30% and the warning goes off when the real capacity is, say, 35%, then that would be bad, but I kind of doubt they'd risk the kind of bad press that would result if discovered.

    Still, a reduction in capacity of 10% in 12 uses seems pretty high and would not have expected that much of a decline in less than perhaps 50 uses. I guess it somewhat depends on how low you run the battery on average and I'd surmise that not running below 30% would be better for pack lifespan than routinely running the pack down to, say, 15%.


    Brian
     
    Scotflieger and eldorado like this.
  15. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    Agreed, yeah. Brian how about yours? Can you possibly list some of your TB48's capacity numbers for comparison? Just trying to see if mine are out of the ordinary or if this is just typical.
     
  16. RaptorMan

    Joined:
    Dec 18, 2015
    Messages:
    770
    Likes Received:
    214
    I have a max of two flights on any battery and so far HealthyDrones is reporting 5681mahr on all the TB48's that I've used. So, too soon to say...


    Brian
     
  17. Yapper915

    Joined:
    Jan 18, 2016
    Messages:
    25
    Likes Received:
    11
    Zar Pk likes this.
  18. Fanti

    Joined:
    Nov 18, 2013
    Messages:
    246
    Likes Received:
    73
    Have exactly the same thing on several TB48s. Crappy batteries.
     
    damoncooper likes this.
  19. Mad_angler1

    Joined:
    Dec 9, 2015
    Messages:
    440
    Likes Received:
    160
    Just one note on the the calibrating picked up on other forums from folks trying to get back small losses in capacity, sub 400mah

    Not all packs will come back to 100% if its capacity has acuatly reduced, your calibrating may be spot on based on the packs voltage curve.

    Sometimes packs even with very low cycles can have a drop in capacity in the short term, this does not mean they will continue to drop at the same rate, some just drop and settle there.

    Also as The Editor pointed out DJI FW is quite harsh on calculating remaining capacity and that's not a bad thing TBH as the last thing you want is a overestimation of what's left, another affect would be the battery temperature when calibrating as if it's cold the cells will sag a little more and give the fuelguage the impression the cells have lost more than they really have.

    Personally i would calibrate at the temperature you intend to fly the batteries if not a little warmer and then fly 20 flights with what ever the capacity comes back to then calibrate again

    But you can't recover capacity they may not have, recent updates do seem to have changed how it's reported as well.

    To a point its irrelevant what the remaining capacity is showing all that maters is you have a stable pack with acurate remaining capacity and not seeking large cell deviation or sagging in flight, a few hundred mAh reduction in reality will not make a huge difference in the real world and your actual flight times will give you a true picture of what's happening.

    Lastly the one thing that's very apparent recently is keep the packs warm, this makes a huge difference in their behaviour.

     
    #19 Mad_angler1, Jan 24, 2016
    Last edited: Jan 24, 2016
    The Editor likes this.
  20. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    3,457
    Likes Received:
    1,631
    Location:
    Boston, MA
    Ok I got my mah back. Here's how.

    I was down to 5136mah on a 5700mah TB48 and now I'm back to 5667mah capacity.

    The DJI battery firmware depletes "capacity" based on some mysterious and quite aggressive factors. I had lost 10% of my TB48's capacity in just 12 charges and set out to try to get my mah back.

    Note: if you are uncomfortable opening a DJI battery top, stop here.

    Follow this procedure to the letter, especially the "wait 60 min" part, then charge and fly your battery down and repeat. By the end of the first cycle (charge, fly, charge), your battery capacity should be restored.

    1. Carefully detach the battery’s top cover – a fine knife or flat head screw driver will allow you to easily unclip the cover.

    2. Gently disconnect the balance plug / loom to the IC. Let it sit unplugged for 60 minutes.
    Reattach the plug / loom.

    3. Fully charge your battery and do two full cycle at low level hover.

    4. Condition your battery and you are good to go.

    Below are the before and after pics of the same battery.

    Have fun!

    ImageUploadedByTapatalk1453729335.563820.jpg
    ImageUploadedByTapatalk1453729366.709702.jpg
     
    #20 damoncooper, Jan 25, 2016
    Last edited: Jan 25, 2016
    David Baxter and slim.slamma like this.