Cloud King 35A 3400mAh 18650 Bench Test Results...only a 10A battery!

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Mooch

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  • May 13, 2015
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    Tested at 10A-35A constant current and 30A pulsed. These cells were purchased by me for the
    purposes of testing thanks to the wonderful donations from so many of you. Thank you! To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18650, 26650, etc.

    Disclaimer
    The statements, 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 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. My safety precautions are the ones I have elected 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.


    A note regarding current ratings and my testing
    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 continuous. Otherwise they would have listed the current rating with two numbers as other companies have done. Or they would have labeled the rating on the wrap as "pulse" or "burst". Battery buyers should not have to hunt down what the number on the wrap means. I will be testing batteries at the rating listed on the wrap and pointing out when they fail to meet that listed rating.

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


    Bottom Line
    In my opinion this is only a 10A battery with a wildly exaggerated rating. Its appearance and performance are the same as the 10A 3200mAh LG MH1 which is the same one that Efest uses in their "35A" 3000mAh battery.


    Continuous-Current Test Results
    image.jpg


    Pulsed-Current Test Results
    These tests are done to show the performance of the cell at higher pulsed current levels. If you are running your mod at these levels be aware that you risk overheating, and possibly venting, the battery if there is a malfunction or accidental pressing of your mechanical mod's button.
    image.jpg


    Comments
    • At 10A it reached 2850mAh. This is terrible performance for a 3400mAh-rated cell.
    • Its temperature at 10A was 76°C, just below the average for a cell operating at its CDR.
    • At 15A the temperature rose to 101°C. This is an astoundingly high temperature and would most likely lead to accelerated damage to the cell if the discharge was repeated.
    • A discharge at 35A, the cell's rating, shows the voltage instantly collapsing down to the 2.8V cutoff. This is clearly not a 35A cell.
    • I am setting a CDR of 10A for this cell since its operating temperature is at the average for a cell operating at its CDR. While operating any cell near its rated maximum current causes damage to the cell, I would expect decent cycle life from this cell at 10A.
    • 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

    18650 Safety Grades -- Picking a Safe Battery to Vape With | E-Cigarette Forum

    26650 Safety Grades and Pulse Performance Data | E-Cigarette Forum
     
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