MXJO Yellow/Silver 35A 3000mAh 18650 Bench Retest Results...a dangerously overrated 15A battery!

[Mooch]

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.




Bottom Line
This is a dangerously overrated and rewrapped cell which I am rating at 15A. 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. These MXJO's are identical in appearance and performance to the Samsung 30Q.

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



Pulse-Current Test Results



"Type- 2" Version Photo



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 15A 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 15A 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/f...afety-grades-and-pulse-performance-data.7566/
https://www.e-cigarette-forum.com/f...des-picking-a-safe-battery-to-vape-with.7447/
https://www.e-cigarette-forum.com/f...fety-grades-and-pulse-performance-data.7554//