Tested at 10A-40A constant current and 30A-60A pulsed. These cells were donated by Tesiyi 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 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 batteries 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.
This cell is double wrapped. The white wrap in the photo above was underneath the yellow/black one.
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 cells at the rating listed on the wrap and pointing out when they fail to meet that listed rating.
Bottom Line
In my opinion, this is not a 40A or 2600mAh cell. It is, however, a decent performing 25A continuous discharge current (CDR) cell with a rated capacity of about 2300mAh. It can be run at beyond its CDR without dangerously overheating, though the voltage drops a lot.
Tesiyi's discharge graphs on their web site are significantly different (better performing) from the ones I created when testing four of these cells. I am unable to explain this discrepancy.
Tesiyi web site rating for the cell
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, the battery if there is a malfunction or accidental pressing of your mechanical mod's button.
Comments
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
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 batteries 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.
This cell is double wrapped. The white wrap in the photo above was underneath the yellow/black one.
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 cells at the rating listed on the wrap and pointing out when they fail to meet that listed rating.
Bottom Line
In my opinion, this is not a 40A or 2600mAh cell. It is, however, a decent performing 25A continuous discharge current (CDR) cell with a rated capacity of about 2300mAh. It can be run at beyond its CDR without dangerously overheating, though the voltage drops a lot.
Tesiyi's discharge graphs on their web site are significantly different (better performing) from the ones I created when testing four of these cells. I am unable to explain this discrepancy.
Tesiyi web site rating for the cell
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, the battery if there is a malfunction or accidental pressing of your mechanical mod's button.
Comments
- At 10A it reached about 2025mAh. This is way below the average performance for a 2600mAh-rated cell at 10A. I rate this cell's capacity at 2300mAh.
- At 15A the maximum temperature reached 58°C. This is way below the average temperature of a cell operating at its continuous discharge rating (CDR).
- At 20A the maximum temperature reached 68°C. This is below the average temperature of a cell operating at its continuous discharge rating (CDR). Its continuous-current performance is a lot better than the Samsung 25R due to its voltage staying higher but the pulse performance shows the lower capacity of the Tesiyi. The 25R is a better performer when pulsed.
- At 25A the temperature rose to 78°C. This is average for a cell operating at its CDR.
- At 30A the temperature rose to 86°C. This is too high for a cell operating at its CDR.
- Discharges at 35A and 40A showed increasing voltage sag and loss of capacity. At 40A the voltage quickly collapsed. This is not a 40A cell. Operating temperatures were only moderate though.
- Another two 20A discharges showed that no damage was done to the cell during the previous higher current discharges. This is probably due to the moderate temperatures.
- I am setting a CDR of 20A for this cell. While operating any cell near its rated maximum current causes damage to the cell, I would expect decent cycle life from this cell at 20A.
- I am setting a capacity rating of 2300mAh for this cell.
- I have included pulsed discharges but I haven't set pass/fail standards for pulse testing yet. The discharges were done at 30A-70A, 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
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