Batteries, Resistance, Swelling

Discussion in 'Batteries & Power' started by Mike Reid, Apr 28, 2016.

  1. Mike Reid

    Mike Reid Member

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    I know that there are a ton of threads about this around the web, but I haven't been able to find an answer to my specific issue.

    I have been very diligent with my battery care (never charged over 2C, never left charged for more than a day) over the years and still have all of my original 3 year old freefly 9000mAh 6s batteries performing nearly to the second for flight time. I mainly use my 10000mAh tattu 6s batteries, but ill use the freeflys if I need to get a few more flights while resting the tattus after flying.

    Just last week the batteries started t get a very small amount swollen, almost not enough to see, but you can feel it. When I charge them on either my 308 Duo or hyperion 720i, I can see that my resistance of each cell is very low, somewhere around 1.5-4 per cell when looking at the 308, total of 12-16 total on the hyperion.

    I had always thought that you had a pretty good indicator of battery health from seeing the resistance, but the fact that the packs are swelling a bit tells me otherwise.

    What have others experienced?
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Mike:
    I would just proceed with caution at this point -- I've seen some LiPo's that swell up slightly, but otherwise seem to function fine. In my experience, when the LiPo is not long for this world it takes on the appearance of a guppy -- I mean, you look at it and wonder whether it will explode, it's that swollen...

    I'd also continue to monitor the LiPo's internal resistance as you have been doing.

    Andy
    ----------
    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  3. Scott Montague

    Scott Montague New Member

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    I know this is an old thread, but i have the same swell on a couple of mine, but they seem to work fine.

    One question...What's the best way to discharge for storage? I just finished my last wedding of the year and have 2 brand new batteries (M5) that I need to put away. Thanks!
     
  4. Michael McVay

    Michael McVay Active Member

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    What type of chargers do you have? The basic charger that comes with the M5 does not put batteries to store charge but others do if you have something different. If not, you might just have to use them until they get to about 50%.
     
  5. Scott Montague

    Scott Montague New Member

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    thanks for the quick reply.
    I only have the Movi chargers and i wasn't sure what other type of meters I could use. This is my first foray with LiPo batteries.
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Scott:
    If you don't have a charger that can also take a battery to storage charge (either by charging it up, or discharging it down), then you can use a 12v or 24v auto lightbulb (not an LED one!) and connect it up as a dummy load to the LiPo. But only do this if you have a Lipo tester that shows the voltage of each cell otherwise you will over-discharge the LiPo (aka "convert Lipo to a paperweight").

    You want to take each cell down to 3.7 volts for storage.

    The M5 LiPos are 4S (four cells), so the total voltage you need for storage is 4 x 3.7, or 14.8v.

    Andy
     
  7. Mark Hoffman

    Mark Hoffman Active Member

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    Scott

    Do yourself a favor and order one of these https://hobbyking.com/en_us/accuell-s60-ac-charger-us-plug.html
    this $30 charger will keep your M5 batteries in good shape. It can charge, discharge, balance, and put your batts into storage voltage. Freefly should really dump the charger they provide and go with something like this but my guess is they probably would need to go thru the 1000 current chargers they already have on the shelf before they'll switch.

    Mark
     
  8. Scott Montague

    Scott Montague New Member

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    Thank you Andy! I appreciate all the info.

    The MōVI Pro should make all of this much easier. I'm LiPo impaired. Ha
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Scott: In which case, you might find this tutorial on LiPos helpful: http://www.droneybee.com/lipo-battery-tutorial/

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
    Chris Harrison likes this.
  10. Scott Montague

    Scott Montague New Member

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    thank you, sir!
     
  11. Scott Montague

    Scott Montague New Member

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    thanks, Mark!
     

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