Cloud Chaser 40A 2500mAh 18650 Bench Test Results...only a 20A battery but looks/performs like 25R5

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Mooch

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  • May 13, 2015
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    Tested at 10A-40A constant current and 30A-70A pulsed. These cells were donated for testing by Cloud Chaser and used only for testing. 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.

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    Bottom Line
    • In my opinion, this cell only has a 20A continuous rating, or just below that.
    • Its top cap and vent construction is identical to the Samsung 25R5. The can had minor differences.
    • It performed well, almost identical to the 25R5 but hotter.

    A note regarding current ratings and my testing
    If the cell has only one current rating on it 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.


    Continuous-Current Test Results
    image.jpg


    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 regulated mod malfunction or accidental pressing of your mechanical mod's button.
    image.jpg image.jpg


    Cloud Chaser 40A vs Samsung 25R5 Shootout
    image.jpg


    Comments
    • At 10A it reached about 2375mAh. This is very good performance for a 2500mAh-rated cell at 10A.
    • At 15A the maximum temperature reached 69°C. This is below the average temperature of a cell operating at its CDR.
    • At 20A the maximum temperature reached 84°C. This is several degrees above the average for a cell operating at its CDR and just beyond an acceptable range.
    • Its capacity at 20A, down to 3.2V, is about the same as the Samsung 25R but its temperature is several degrees higher.
    • At 25A the temperature rose to 95°C. This is way too high for a cell operating at its CDR and is close to my safety limit of 100°C.
    • A discharge at 40A was done to show the cell's performance at the rating on its wrap. The voltage quickly dropped to 3.3V and the temperature skyrocketed to above my 100°C safety limit before the end of the discharge. This is an unsafe temperature and this is clearly not a 40A cell!
    • After this first 40A discharge, another two 40A discharges were done. The third discharge was plotted and shows the damage done to the cell after just three discharges at that current level.
    • Using another cell, doing six 20A discharges showed that no damage was being done to the cell at that current level.
    • I am setting a CDR of 20A for this cell. Its temperature is high but no damage is seen at this level. By temperature alone, this is about an 18A 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 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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