Efest 18650 3400mAh (Black)

Protected button top

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Official specifications:
Efest%2018650%203400mAh%20bt%20(Black)-info

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The protection does prevent a full 5A discharge curve on one of the batteries. The difference in protection between the batteries is also the reason for the curves not overlapping at the higher currents.
The cell used can be discharged down to 2.5 volt, in my test I only discharges to 2.8 volt, i.e. I do not measure the full capacity. But then, not all lights will be able to use the full capacity.

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Unprotected flat top

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Official specifications:
Efest%2018650%203400mAh%20ft%20(Black)-info

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Efest%2018650%203400mAh%20ft%20(Black)-Capacity

The unprotected version has exactly the same very good performance as other batteries with the same cell.

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Conclusion

Both batteries are very good, the slightly low protection limit is only a problem in special applications (Discharing a 3400mAh battery in less than 40 minutes is not normal usage), not for regular usage.



Notes and links

The batteries was supplied by Efest for review.

How is the test done and how to read the charts
How is a protected LiIon battery constructed
More about button top and flat top batteries