Test/review of Sofirn 21700 4000mAh (Black)

HKJ

Flashaholic
Joined
Mar 26, 2008
Messages
9,715
Location
Copenhagen, Denmark
[size=+3]Sofirn 21700 4000mAh (Black)[/size]

DSC_5281.jpg


Official specifications:
  • Battery Minimum Capacity: 4000-3900mAh
  • Battery Discharge Current: 40A
  • Battery Capacity: 4000mAh
  • Battery Voltage: 3.7V
Sofirm%2021700%204000mAh%20(Black)-info.png


This is a high current 21700 cell with good capacity.

DSC_5282.jpg
DSC_5283.jpg


DSC_5284.jpg

DSC_5285.jpg

DSC_5286.jpg


Sofirm%2021700%204000mAh%20(Black)-Capacity.png


The cells matches very nicely and can deliver a lot of current.
Sorry about the 30A curve, but my battery holder melted at that current and temperature.

Sofirm%2021700%204000mAh%20(Black)-Temp-10.0.png


Sofirm%2021700%204000mAh%20(Black)-Temp-15.0.png


Sofirm%2021700%204000mAh%20(Black)-Temp-20.0.png


firm%2021700%204000mAh%20(Black)-CapacityTimeHours.png


Sofirm%2021700%204000mAh%20(Black)-CapacityTime.png


Sofirm%2021700%204000mAh%20(Black)-Energy.png


Sofirm%2021700%204000mAh%20(Black)-PowerLoadTime.png


Sofirm%2021700%204000mAh%20(Black)-TripCurrent.png


Sofirm%2021700%204000mAh%20(Black)-Charge.png


700%204000mAh%20%28Black%29-pulse-1.0%2010%2010-IR.png




[size=+3]Conclusion[/size]

This is a good cell that can deliver a lot of current, but using well above 20A will need a thermal cut-out.



[size=+3]Notes and links[/size]

The batteries was supplied by Sofirn 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
Graphical comparison to 18650 and other batteries
Table with all tested LiIon batteries
 
Top