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Bench Test Results: CoilArt 40A 4000mAh 21700…grotesquely overrated, a poor 20A performer

Discussion in 'Batteries and Chargers' started by Mooch, Nov 11, 2017.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    While the test results are hard data, the conclusions and recommendations I make based on these tests are only my personal opinion based on my criteria for setting a rating. Carefully research any cell you are considering using before purchasing.

    Testing cells 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.

    If the cell has only one current rating number on it, or if it only says "max" then I have to assume that the company is stating that the cell can be discharged at that current level in any way, including continuously.

    Cell photos: https://imgur . com/a/9e0dX
    (Sorry for the split link but direct links to Imgur do not display properly)


    Bottom Line
    This is a poor performing 21700 cell with a preposterous 40A rating. It appears almost identical to the Basen 30A 4000mAh 21700 but performs a bit worse than the Basen.

    Its 40A rating can’t even be considered a “pulse” or “max” rating as it drops to under 3.2V for the first pulse, freshly charged. This is clearly not a 40A cell.

    It performs worse than the iJoy 40A 3750mAh 21700. The CoilArt’s greater voltage sag results in at least 30% less vaping time at moderate to high current levels.

    Its capacity falls short of 4000mAh in my testing. Since I’m sure I don’t have the worst performing examples of this cell out there I have to assume that others will test even a bit lower.

    I am rating this cell at 20A and 3850mAh. Its maximum vaping amps (MVA) limit is 25A, limited by temperature and voltage sag. I recommend staying below about 40W though to prevent excessive voltage sag and reduced vaping time.

    This cell has a plastic top insulating ring so juice spills shouldn’t damage the ring.

    Two cells from The Cloudy Vapor (www.thecloudyvaper.com) and two from CoilArt were donated for the purposes of testing. Thank you!


    Continuous-Current Test Results
    CoilArt 40A 4000mAh 21700 CC Tests.jpg CoilArt 40A 4000mAh 21700 Capacity Test.jpg CoilArt 40A 4000mAh 21700 CC Tests vs Others.jpg


    Pulse-Current Test Results
    CoilArt 40A 4000mAh 21700 Pulse Tests.jpg CoilArt 40A 4000mAh 21700 Pulse Tests ZOOMED.jpg


    Comments
     
    • Like Like x 4
  2. Katya

    Katya ECF Guru Verified Member ECF Veteran

    Supporting member
    Feb 23, 2010
    SoCal
    Thanks, Mooch. As always! :)
     
    • Like Like x 1
  3. sonicbomb

    sonicbomb Vaping Master Verified Member ECF Veteran

    Feb 17, 2015
    1187 Hunterwasser
    It seems that re-wrappers are using the 20700 21700 format as a reason to exaggerate performance claims even more than 18650s
     
    • Agree Agree x 1
  4. mjag

    mjag Super Member Verified Member ECF Veteran

    Jan 8, 2014
    United States
    Thanks as always @Mooch

    There is a sale on these but after seeing this I will pass.
     
    • Agree Agree x 1

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