Welcome to InspirePilots.com

Join the leading DJI Inspire community for free!

School me: Battery % vs V

Discussion in 'General Discussion' started by Charles.mabry, Sep 15, 2016.

  1. Charles.mabry

    Joined:
    Mar 22, 2016
    Messages:
    123
    Likes Received:
    14
    Location:
    Prescott, Az
    Ok, gents. Sometimes things just dont "click" with me... Im a very hands on person and sometimes its a bit difficult just reading something and fully comprehending whats going on. Thats why I despise the FAR's haha.

    Ive never been able to fully grasp what is going on with the % vs V on the battery life and my last flight was a quick reminder I need to get my butt in gear. I updated the controller, battery, and aircraft. Went out flying and my battery suddenly dropped to 30% out of nowhere. I was only doing some flights testing video modes so I quickly flew it home. Im currently doing the battery reset but want to learn more about the % vs V.... If you guys could help me out that would be great!

    Thanks in advance.
     
  2. The Editor

    The Editor Moderator
    Staff Member

    Joined:
    Aug 7, 2013
    Messages:
    6,703
    Likes Received:
    3,861
    I'm afraid that's vertually impossible to correlate
    Percentage v voltage is one of those things that if you ask 10 people you will get 10 different answers.
    Personally I never fly by percentage as it is just not accurate.
    I fly by voltage which is absolute.
    I normally fly (land) at circa 3.45v per cell under load.
    Once landed, the rebound will bring the pack up to around 3.7v per cell which is perfect.

    Trying to get an absolute figure for voltage v percentage will have you tearing your hair out because the discharge curve of a Lipo is very flat up until the plateau where it drops off rapidly.
    Additionally any graphs you may find on the internet showing voltage against percentage are almost certainly for standard Lipos whereas the Inspire packs are HV Lipos which push the cell voltages higher than 4.2v. :)
     
    Alastair, x5yo and Charles.mabry like this.
  3. Charles.mabry

    Joined:
    Mar 22, 2016
    Messages:
    123
    Likes Received:
    14
    Location:
    Prescott, Az
    Thank you! that gives me a little more to go off of!
     
  4. emtea

    Joined:
    Nov 16, 2015
    Messages:
    124
    Likes Received:
    41
    I use the voltage as an indication of how much punch I have left in the battery. I never really pay attention to flight times, I'm focused on getting where I need the bird and taking the shot. That being said, I get uncomfortable anywhere below 3.70V--in the sense that once I'm under 3.70V I will not fly full sticks and will go easy on maneuvers and will try to avoid rapid ascent + motion.

    Not sure if that makes sense to you, but hopefully it's helpful. You'll notice that going full forward or up will cause the voltage to drop suddenly compared to hover. The idea is to stay above 3.70V at all times (for me personally).
     
    Pescatoral Pursuit likes this.
  5. Pescatoral Pursuit

    Joined:
    Mar 29, 2016
    Messages:
    162
    Likes Received:
    54
    Location:
    Orlando
    It helps to regard it as NOT a completely accurate measurement. More of a guideline as it were...
     
  6. atlav8r

    Approved Vendor

    Joined:
    Oct 17, 2014
    Messages:
    14
    Likes Received:
    0
    Location:
    North Atlanta GA
    How many cycles on the pack in question?
    Pull up the battery screen in the app when flying. It sounds like you could be in the beginning stages of a cell going bad. Watch the individual cell balance as you run it and see if you are getting indications of a cell going bad.