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Vamped Black 40A 2300mAh 18650 Bench Test Results...a 20A/1800mAh battery, no higher

Discussion in 'Batteries and Chargers' started by Mooch, Jul 23, 2015.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Tested at 10A-30A constant current. This cell was purchased from IMRBatteries and donated for testing. To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18650, 26650, etc.

    image.jpg image.jpg image.jpg image.jpg

    Disclaimer
    The conclusions and recommendations I make based on these tests are only my personal opinion. Carefully research any battery you are considering using before purchasing.

    Testing batteries at their limits is dangerous and should never, ever, be attempted by anyone who has not thoroughly studied the dangers involved and how to minimize them. My safety precautions are the ones I have selected to take and you should not assume they will protect you if you attempt to do any testing. Do the research and create your own testing methods and safety precautions.


    Bottom Line
    This is a 20A continuous discharge current (CDR) cell that clearly gets damaged at 30A. Even at only 10A it barely reached 1600mAh. In my opinion this is not a 40A cell and you should not run it above 20A.


    Test Results
    image.jpg

    Comments
    • At 10A the discharge barely reached 1600mAh. I would have expected it to go out to at least 2000mAh if this was a true 2300mAh cell. I'm giving it a capacity rating of 1800mAh.
    • At 20A the cell had a moderate maximum temperature of 79°C.
    • At 25A the cell reached a max temperature of 91°C. This is a way too high a temperature for a cell to operate at,
    • At 30A it reached 99°C, only one degree below my safety limit of 100°C. This is clearly not a 40A cell.
    • Discharges were not done at 35A or 40A due to the very high temperature seen during the 30A test.
    • An additional cycle at 20A showed clear signs of damage from the one 30A (and possibly the one 25A) discharge; voltage sag, reduced capacity, and increased temperature.
    • I am setting a CDR of 20A for this cell. I think you will get decent cycle life due to the moderate temperature at that current level. In my opinion you should not run this cell at above 20A though!
     
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  2. Cullin Kin

    Cullin Kin Ultra Member Verified Member ECF Veteran

    Jun 28, 2014
    The 3Oh!3, Colorado
    Thanks again Mooch. I cannot stand these rewrap companies that claim these dangerously false CDR's. By chance, did you remove the wrapper and see what code was printed on the cell?
     
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  3. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    The only code visible was that 4 character string shown in the case photo. Didn't seem familiar. You might have to compare cell tops to narrow down what they rewrapped.

    [edit] sorry, 5 characters, "14K12"...actually, it does sound familiar but I don't remember why.
     
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  4. Cullin Kin

    Cullin Kin Ultra Member Verified Member ECF Veteran

    Jun 28, 2014
    The 3Oh!3, Colorado
    Shows how blind I am... Totally missed those photo's. My bad!
     
  5. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Edited my previous post and included the code as the photograph didn't make it very clear.
     
  6. Cullin Kin

    Cullin Kin Ultra Member Verified Member ECF Veteran

    Jun 28, 2014
    The 3Oh!3, Colorado
    After employing some google-fu, it seems that the 14K12 is some sort of date indicator? Maybe...
     
    • Like Like x 1
  7. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Doh! That sounds plausible. But which to which cell does that code belong to? :)
    I think some day I'll have to gather and sort the cell top pictures I have all into one blog to make this kind of stuff easier.
     
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