Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Voltage Question

Discussion in 'Pro/Adv Discussion' started by nollzr, Apr 22, 2016.

  1. nollzr

    Joined:
    Jan 1, 2016
    Messages:
    87
    Likes Received:
    8
    Was flying this evening and noticed my voltage number was turning orange under my battery percent on the dji app. Think it said 3.60v. My battery was still at 42% and everything seemed normal, but I landed anyway to be on the safe side. I would like to think I can get another 15% or so out of the battery on each flight. Is this a normal occurrence?
     
  2. Waylander

    Joined:
    Jul 14, 2015
    Messages:
    332
    Likes Received:
    82
    Location:
    UK
    Hi Nollzr

    I believe a voltage of 3.60v is quite low, and I would be thinking about landing at that kind of reading, have a look at your flight log for that flight, make sure that all of the cells show a similar voltage level, it may have been the case that the Go app was reporting the lowest cell reading. You dont say what the ambient air temperature was when you were flying, if it was cold this will effect usable battery life.
    There is a wealth of discussion in the forum regarding battery voltage problems.
    for example here is one.

    Phantom 3 Critically low Voltage battery failure brings aircraft down

    Regards
    Waylander
     
  3. nollzr

    Joined:
    Jan 1, 2016
    Messages:
    87
    Likes Received:
    8
    Thanks Waylander, I will check it out. The temp outside was around 67 degrees F.
     
  4. arcaine25

    Joined:
    Jan 28, 2016
    Messages:
    199
    Likes Received:
    68
    I too had the same issue when flying my Phantom 4 the other day, and was also around the 42% mark. I remember thinking just as you that it was odd to be THAT low on voltage, but still have 42%ish remaining / reported. To take note, I slowed down, hovered and it jumped back up... I was in sport mode being crazy (crazy AND responsible lol) so, as with any UAV i've piloted, as well as my custom builds, when you juice the throttle it puts a decent drain on the cells. This is typically, in my experience, due to a lower "C" rating of the batteries. I wonder what the DJI smart batteries are rated at C wise... Now I will have to find that out!

    Side note though, I stayed in the air, and flew more "normal" and not full tilt, and all was well until I landed at around 18%
     
  5. Waylander

    Joined:
    Jul 14, 2015
    Messages:
    332
    Likes Received:
    82
    Location:
    UK
    Hi nollzr

    Another though occurred to me, have you "Run the batteries in", ie did you drain the batteries to around 40% and then recharged them to 100% on ten occasions, this for want of a better word "hardens" them, you will get longer service and longer flight times by doing this and it will allow for a much higher instant discharge current, search the forum you will find lots of discussion.
    Here is a very in depth article on LIPO's

    A Guide to Understanding LiPo Batteries - Roger's Hobby Center - Radio Control (R/C or RC) Cars, Boats, Airplanes, Puzzles, Plastic Models, & Trains - Saginaw, MI

    Regards
    Waylander
     
  6. arcaine25

    Joined:
    Jan 28, 2016
    Messages:
    199
    Likes Received:
    68
    I've never heard of this, I will have to research it. Anybody have any personal experience with this?
     
  7. msinger

    Approved Vendor

    Joined:
    Oct 30, 2014
    Messages:
    18,990
    Likes Received:
    5,594
    Location:
    US
    It's okay to fly until the first battery cell reaches 3.4V. See more details here.
     
  8. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,143
    Likes Received:
    1,659
    Location:
    San Francisco, CA
    As a thumb rule, you can rely on the gauge used by P3 to show % charge shown on the Go App if your flight was steady. If you had frequent inrush of currents due to sudden speeding ups etc, gauge may not be accurate and will display higher than actual remaining charge. FW1.6 had improved the predictions. Predictions also may go wrong if batteries were not charged fully before taking off. There are other factors like operating temperatures that also should be taken into account.

    DJI has done their best to map all this into intelligence through Battery FW but the displayed values are calculated % charge values and may go wrong. As a thumb, shown charge levels are the vacillated numbers and actual may be equal or less than the displayed values.

    I always start planing to land when I see 30% remaining charge and definitely land by the time it is closer to 20%.
    My flying is not aggressive and I can rely on the displayed values.
     
    arcaine25 likes this.
  9. Trackman1

    Joined:
    Jan 1, 2016
    Messages:
    838
    Likes Received:
    212
    Location:
    Ontario, Canada
    The cooler the battery the more you get the amber cells.
    I got my P3 in Feb. So I started flying in 0C conditions. (those were the warm days.)
    Battery might get to 30c by landing.
    At first I was blissfully ignorant as I did not have the "show voltage on screen) option turned on.
    But after engaging that option.
    Amber cells started at 50% battery. Even just hovering at 42% they would be amber.
    But as the outside temp has risen the battery is warmer and the cells turn amber at lower %.

    I find these battery's don't start to perform well until 40c

    After amber there are red cells. And somewhere in there you get the propulsion cut message.

    Next winter I am going to warm my battery's before flight.
     
  10. msinger

    Approved Vendor

    Joined:
    Oct 30, 2014
    Messages:
    18,990
    Likes Received:
    5,594
    Location:
    US
    Be careful with relying on that calculated battery percentage as an indicator for when you should be landing. The battery voltage is all that really matters.
     
    N017RW likes this.
  11. lookin4pain

    Joined:
    Dec 25, 2015
    Messages:
    175
    Likes Received:
    93
    Location:
    Oregon
    I think a few others have said this, the voltage drops considerably when flying aggressive. If you're concerned about seeing below 3.6, back off and you should see the voltage rise a little. Usually works for me. I just hope to never see 3.4 when I'm flying...


    Sent from my iPad using PhantomPilots mobile app
     
    arcaine25 likes this.
  12. Trackman1

    Joined:
    Jan 1, 2016
    Messages:
    838
    Likes Received:
    212
    Location:
    Ontario, Canada
    Very true Lookin. 2 days ago I got propulsion reduced message at 4m41s. I was 3.3km out and had been full forward nearly the entire time.
    So I started RTH. which does not go full throttle. After 9 minutes total time I had more voltage than I had at 4m41s.

    From Msingers log viewer.

    4m 41.9s 29.3mph 10,673.6ft 75% 14.326V 3.55V 3.599V 3.624V 3.553V 0.074V Propulsion Output Limited
    9m 1s 21.4mph 3,136.2ft 56% 14.727V 3.666V 3.693V 3.703V 3.665V 0.038V
     
  13. Sunny1975lucky

    Joined:
    Jan 5, 2016
    Messages:
    28
    Likes Received:
    5
    Happens with all three of my batteries at about the same percentage. I still run them down to about 25% and land without any problems. I always hover for a few minutes at the start to warm the batteries up to 25c before giving it full power.
     
  14. grottoli

    Joined:
    Jan 11, 2016
    Messages:
    32
    Likes Received:
    13
    Location:
    Peel Region
    This is why I put the battery info panel on the C2 button on the RC. I can toggle to it for a quick voltage check from time to time. Very handy.

    Happy Flying


    Sent from my iPad using PhantomPilots mobile app
     
  15. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,143
    Likes Received:
    1,659
    Location:
    San Francisco, CA
    It's not always true. We should rather monitor both.