These cells were donated for the purposes of testing by Efest. 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 metallic-appearing wrap Efest cell is a decent performer and I rate it at 10A. Its capacity is high for its rating so I am rating it at 1100mAh. The performance of the four cells I tested was inconsistent though. Not bad enough to prevent testing but it seems that 18500's may suffer from the same inconsistency I often see in 18350's. Time will tell as I test more 18500's. This Efest lists both the continuous and pulse ratings on the wrap, which is a good thing, but the pulse rating is printed larger and is meaningless without knowing the pulse width, duty cycle, and the criteria for setting the rating (temperature? run time? voltage sag?).
Continuous-Current Test Results
Pulsed-Current Test Results
Comparison of the four Efest cells
Comments
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
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 metallic-appearing wrap Efest cell is a decent performer and I rate it at 10A. Its capacity is high for its rating so I am rating it at 1100mAh. The performance of the four cells I tested was inconsistent though. Not bad enough to prevent testing but it seems that 18500's may suffer from the same inconsistency I often see in 18350's. Time will tell as I test more 18500's. This Efest lists both the continuous and pulse ratings on the wrap, which is a good thing, but the pulse rating is printed larger and is meaningless without knowing the pulse width, duty cycle, and the criteria for setting the rating (temperature? run time? voltage sag?).
Continuous-Current Test Results
Pulsed-Current Test Results
Comparison of the four Efest cells
Comments
- At 5A continuous it reached about 1067mAh. This is above average performance for a 1000mAh 18500 cell at 5A so I am rating this cell at 1100mAh.
- At 10A continuous the temperature rose to 55°C with decent capacity and no sign of voltage sag.
- At 15A continuous its voltage quickly dropped down to about 3.1V.
- I am setting a CDR of 10A for this cell. Operating at any higher than this causes the voltage to sag excessively. 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.
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
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