XXX 40A 3100mAh 18650 Bench Test Results...exaggerated ratings, looks like 30Q

Discussion in 'Batteries and Chargers' started by Mooch, Aug 12, 2016.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    These cells were donated for the purposes of testing by Mike Vapes. Thank you! To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18350, 18650, 26650, etc.

    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 says "max discharging current" 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.

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    Bottom Line
    This XXX cell has an exaggerated capacity rating and a wildly exaggerated current rating. At 10A below its 40A rating it gets hot enough to boil water and approaches a dangerous temperature. At its 40A rating it only delivers 37mAh down to 3.2V. I am rating it at 20A continuous and 3000mAh. This cell looks and performs essentially identically to the 20A/3000mAh Samsung 30Q. I am giving this cell a maximum vaping amp (MVA) rating of 25A.

    The 18650 ratings table has been updated to include this cell.


    Continuous-Current Test Results
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    Pulsed-Current Test Results
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    Comments
    • At 10A continuous it reached 2828mAh. This is a average performance for a 3000mAh cell at 10A so I am rating this cell at 3000mAh.
    • At 15A continuous the temperature rose to 69°C. This is below the average temperature of a cell running at its continuous discharge rating (CDR).
    • At 20A continuous the temperature rose to 79°C. This is the average temperature of a cell running at its CDR and an indication that we are at its true rating.
    • At 25A continuous the temperature rose to 92°C. This is an incredibly high temperature and an indication that we are operating at way above its CDR.
    • At 30A continuous the temperature rose to 105°C. This is above my safety limit of 100°C and an indication that it should not be used at this level in case there is a mod malfunction or accidental button press. I am giving this cell a maximum vaping amp (MVA) rating of 25A.
    • At 35A and 40A there was a ridiculous amount of voltage sag and extremely high temperature at 35A, 104°C. It only delivered 37mAh at 40A down to 3.2V. This is clearly not a 40A cell.
    • I am setting a CDR of 20A for this cell. While operating any cell near its rated maximum current level causes damage to the cell, I would expect decent cycle life from this cell at 20A continuous.
    • I have included pulsed discharges but I haven't set pass/fail standards for pulse testing yet. The discharges were done at 5sec on/30sec off, down to 2.5V. One chart shows the entire discharge at each level. The other chart is zoomed in to show the first 5 minutes to make it easier to see the voltage sag at different current levels.
    To see how other cells have tested and how hard you can safely push them, check out these links:
    List of Battery Tests | E-Cigarette Forum
    18350/18500 Safety Grades and Pulse Performance Data | E-Cigarette Forum
    18650 Battery Ratings -- Picking a Safe Battery to Vape With | E-Cigarette Forum
    26650 Safety Grades and Pulse Performance Data | E-Cigarette Forum
     
  2. sonicbomb

    sonicbomb Vaping Master Verified Member ECF Veteran

    Feb 17, 2015
    1187 Hunterwasser
    Another for the rogues gallery
     

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