This is a poor performing 21700 cell with a preposterous 40A rating. It appears almost identical to the Basen 30A 4000mAh 21700 but performs a bit worse than the Basen.
Its 40A rating can’t even be considered a “pulse” or “max” rating as it drops to under 3.2V for the first pulse, freshly charged. This is clearly not a 40A cell.
It performs worse than the iJoy 40A 3750mAh 21700. The CoilArt’s greater voltage sag results in at least 30% less vaping time at moderate to high current levels.
Its capacity falls short of 4000mAh in my testing. Since I’m sure I don’t have the worst performing examples of this cell out there I have to assume that others will test even a bit lower.
I am rating this cell at 20A and 3850mAh. I recommend staying below about 40W though to prevent excessive voltage sag and reduced vaping time.
This cell has a plastic top insulating ring so juice spills shouldn’t damage the ring.
Two cells from The Cloudy Vapor (www.thecloudyvaper.com) and two from CoilArt were donated for the purposes of testing. Thank you!
Cell photos: https://imgur.com/a/9e0dX
Ratings graphic: https://imgur.com/a/AW6SX
Test results, discharge graph, photos: https://www.e-cigarette-forum.com/forum/threads/bench-test-results-coilart-40a-4000mah-21700…grotesquely-overrated-a-poor-20a-performer.837019/#post-20222177
All my test results to date: https://www.e-cigarette-forum.com/forum/blog-entry/list-of-battery-tests.7436/