A BATTERY MOOCH POST: iJoy 40A 3750mAh 21700…hugely overrated but better than NCR20700B

This cell has “40A” on the wrap which is far, far above its true rating of 24A. It’s capacity is also exaggerated and averages only 3650mAh for the three cells I tested.

I have spoken to iJoy though and they have agreed to rewrap the cell using more realistic ratings. I will retest when the new wrap is available.

There was a greater than typical variation in the capacities of the three cells I tested. It almost appears that there is no grading by capacity for the cells coming off the assembly line. It would take several days of testing to determine the true capacity rating of this cell but the 3650mAh rating I am giving it is close to its true rating.

This cell is outperformed by the 40A 3000mAh iJoy/Ampking/EBAT/Efest 20700 which hits harder and runs just as long at moderate to high power levels. I recommend using this cell at power levels of 50W or less to help prevent voltage sag from giving you early weak/low battery alerts in a regulated mod.

This iJoy cell does outperform the 15A 4000mAh Sanyo NCR20700B cell though.

While I am extremely disappointed with the degree of overrating of this cell by iJoy I am glad that they are willing to rewrap it with more realistic ratings.

This cell is not a rewrap of any other 21700 that I am aware of. I am rating this iJoy cell at 24A and 3650mAh.

The two cells that were tested were purchased for that purpose by me.

Test results, discharge graph, photos: https://www.e-cigarette-forum.com/forum/threads/bench-test-results-ijoy-40a-3750mah-21700-hugely-overrated-but-better-than-ncr20700b.827513/

All my test results to date: https://www.e-cigarette-forum.com/forum/blog-entry/list-of-battery-tests.7436/

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Author: John Muchow