XTAR Black 35A 3200mAh 26650 Bench Test Results...a good 25A 3500mAh battery

[Mooch]

These cells were donated for the purpose of testing by Origin vape (www.originvape.com). 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.


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 continuously.




Bottom Line
This is a good 26650 cell, testing out at 25A continuous and 3500mAh. It uses the same cell as the MXJO Yellow 35A 3500mAh and MNKE Orange 35A 3500mAh (narrow-spaced lines of text) under the wrap. The 4200mAh/4500mAh 26650's that did well in my testing (Basen, Brillipower, Efest) run at a slightly lower voltage than the xtar but have higher capacity.


Continuous-Current Test Results



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 of, the battery if there is a malfunction or accidental pressing of your mechanical mod's button.



Comments

• At 10A continuous it reached about 3480mAh. This is far beyond what a 3200mAh cell is able to do. It's great performance for a 3500mAh-rated cell operating at 10A so I am rating this cell at 3500mAh.
• At 15A continuous the temperature rose to 57°C. This is significantly below the average temperature for a cell operating at its continuous discharge rating (CDR).
• At 20A continuous the temperature rose to 65°C. This is still significantly below the average temperature for a cell operating at its CDR.
• At 25A continuous the temperature rose to 73°C. This is a few degrees below the average temperature for a cell operating at its CDR.
• At 30A continuous the temperature rose to 80°C. This is a couple degrees above the average temperature for a cell operating at its CDR, indicating that we are operating above the cell's rating. The voltage is starting to sag and recover near the beginning of the discharge, also indicating that we are operating above the cell's rating.
• At 35A continuous the temperature rose to 87°C. This is significantly above the average temperature for a cell operating at its CDR. The voltage is sagging a lot now and the capacity has dropped too. This is clearly not a 35A battery.
• Two more discharges at 35A shows clear damage to the cell, its voltage being lower than during the first 35A discharge.
• A single discharge at 40A brought the cell to 91°C. Its voltage was low, sagging, and the capacity has decreased significantly.
• I am setting a CDR of 25A for this cell. While its temperature is lower than average at this current level, 26650's are hotter inside than 18650's. Quick damage occurred at 35A and I don't think rating this cell at 30A would ensure a long cycle life. 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 25A 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 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