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MXJO Yellow/Silver 35A 3000mAh 18650 Bench Retest Results...a dangerously overrated 20A battery!

Discussion in 'Batteries and Chargers' started by Mooch, Oct 15, 2016.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    These cells were purchased with funds donated by the vaping community for the purposes of testing. 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.

    image.jpeg image.jpeg image.jpeg image.jpeg


    Bottom Line
    I know that many of you are vaping with this cell successfully at 30A and higher. Any decent 20A cell can be pulsed to at least 40A. This MXJO isn't dangerous because it gets too hot when being vaped with at those levels. It's dangerous because it might vent if used within its claimed rating and there is a problem with the mod or an accidental button press.

    This is a dangerously overrated and rewrapped cell which I am rating at 20A. When discharged at its 35A rating it reached a temperature of 122°C, tied for the highest I've ever seen. It was badly damaged after a single 35A discharge. It's maximum vaping amps (MVA) rating is 25A. These MXJO's are identical in appearance and performance to the Samsung 30Q.

    My previous testing found this MXJO to be HG2 and 30Q rewraps. Why didn't I rate this as a dangerous cell then? I never thought people would continue to use it at higher discharge current levels when they found out it was a 30Q or HG2 (depending on which version you got). I am now spending more time testing at higher current levels to find which batteries get dangerously hot at up to their claimed rating, not just their actual rating.

    Each of us has to decide whether all this is a concern or not. I am not judging your decision to buy or use this cell, just reporting its true ratings and any risks in using it. As it is a rewrapped 30Q, it is not unsafe to use anywhere a 30Q can be used.

    Another version of this battery with "Type- 2" and "20A CDC" on the bottom of the back side of the wrap is being sold. I assume that CDC = Continuous Discharge Current but the front of the wrap only says 35A. The MXJO web site does not show or mention this "Type- 2" cell.

    This version of this cell has a 3-prong top contact. I don't know if the 4-prong version, an LG HG2 rewrap, is still being sold.

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


    Continuous-Current Test Results
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    Pulse-Current Test Results
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    "Type- 2" Version Photo
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    Comments
    • At 10A continuous it reached 2752mAh. This is average performance for a 3000mAh cell at 10A so I am rating it at 3000mAh.
    • At 15A continuous the temperature rose to 70°C. This is below the average temperature of a cell operating at its continuous discharge rating (CDR) and is an indication that we are operating below its true rating.
    • At 20A continuous the temperature rose to 81°C. This is just above the average temperature of a cell operating at its CDR and is an indication that we are operating near its true rating.
    • At 25A continuous the temperature rose to 97°C. This is incredibly hot and clearly shows that we are operating at above the cell's CDR.
    • At 30A continuous the temperature rose to 108°C. This is above my 100°C safety limit and is approaching dangerous levels.
    • At 35A continuous the temperature rose to 122°C. This is one of the highest temperatures I've ever seen for a cell operating at or under its claimed rating and the cell is in danger of venting. The voltage is sagging considerably and the cell only delivers 137mAh down to 3.2V.
    • A second discharge at 35A clearly shows how badly damaged the cell was by a single discharge at its 35A rating.
    • 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.
    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
    https://www.e-cigarette-forum.com/forum/blog-entry/18350-safety-grades-and-pulse-performance-data.7566/
    https://www.e-cigarette-forum.com/forum/blog-entry/18650-safety-grades-picking-a-safe-battery-to-vape-with.7447/
    https://www.e-cigarette-forum.com/forum/blog-entry/26650-safety-grades-and-pulse-performance-data.7554//
     
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