AOSO Brown 25A 3500mAh 18650 Bench Test Results...only a 10A battery, probably MJ1

[Mooch]

These cells were purchased for the purposes of testing by me. 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 only a 10A cell with a very exaggerated current rating. It does meet its 3500mAh rating though. At only 15A continuous its temperature rose to 104°C, above my 100°C safety cutoff. When discharged at its 25A rating its voltage collapses and it delivers less than 10mAh down to 3.2V. Yes, only 10mAh. Its appearance and performance are the same as the LG MJ1.

The 18650 ratings table has been updated to include this cell. As with any non-Samsung/Sony/LG/Panasonic/Sanyo cell, what they use under the wrap can change at any time.


Continuous-Current Test Results



Pulsed-Current Test Results
Pulsed testing could not be done as both cells were damaged during the continuous current testing.


Comments

• At 10A continuous it reached about 3000mAh and 71°C. This is about average performance for a high internal resistance 3500mAh cell. I am rating this cell at 3500mAh.
• At 15A continuous the temperature rose to 104°C. This is a ridiculously high temperature and is way above the average temperature of a cell running at its continuous discharge rating (CDR). There is a lot of voltage sag and loss of capacity.
• At 20A continuous the temperature rose to 78°C. This is lower than the 15A discharge temperature because the voltage has sagged so much that the discharge was very short before reaching my cutoff voltage.
• At its 25A rating the voltage instantly plummeted to 3.2V and then quickly dropped to my 2.8V cutoff. It only delivered about 10mAh down to 3.2V. This is very clearly not a 25A cell.
• I am setting a CDR of 10A for this cell. Operating at that level would bring the temperature near to the average for a high internal resistance cell operating at its CDR. 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 10A 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