Shockli Blue 35A 2500mAh 18650 Bench Test Results...just a 20A battery, looks like 25R

[Mooch]

These cells were donated for the purposes of testing by Shockli. 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 is an overrated cell that I am rating at 20A/2500mAh. While the wrap does list both the continuous and pulse ratings, normally a very good thing, its claimed 35A continuous rating is wildly exaggerated. At 30A continuous, 5A below its claimed rating, it got hot enough to boil water. It looks and performs identically to the Samsung 25R2 and is almost identical in appearance to the 25R5.


Continuous-Current Test Results



Pulsed-Current Test Results



Comments

• At 10A continuous it reached about 2400mAh. This is very good performance for 2500mAh cell at 10A so I am rating this cell at 2500mAh.
• At 15A continuous the temperature rose to 65°C. This is way below the average temperature of a cell running at its continuous discharge rating (CDR).
• At 20A continuous the temperature rose to 77°C. This is one degree below the average temperature of a cell running at its CDR and is an indication that we are at the cell's true rating.
• At 25A continuous the temperature rose to 90°C. This is a ridiculously high temperature and a strong sign that we're way above the cell's true rating.
• At 30A continuous the temperature rose to 101°C, above my 100°C safety limit. This is a unsafe temperature and a strong sign that we're way above the cell's true rating.
• A discharge at 35A, the cell's rating, was not done due to the excessive temperature measured at 30A
• I am setting a CDR of 20A for this cell. Operating at that level would bring the temperature up to the average for a 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 20A 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