Samsung INR21700-40T 4000mAh (Cyan)



Official specifications:

• Rated discharge capacity: 3900mAh
• Standard discharge capacity: 4000mAh
• Nominal voltage: 3.6V
• Standard charge: CCCV, 2A, 4.20V, 200mA cut-off
• Rated charge: CCCV, 6A, 4.20V, 100mA cut-off
• Max. continuous discharge: 35A with temperature cut.
• Max. continuous discharge: 45A with 80°C temperature cut.
• Discharge cut-off voltage: 2.5V
• Cycle life: 250 cycles to 60% at 6A charge and 35A discharge.

This is a high current with good capacity in the new 21700 format.










The two cells tracks very well and capacity drops slowly with higher current. I had a slight problem with the B cell, my connection in the battery holder was not good enough and it got hot at 30A.





















Conclusion

It is a very good high current and capacity cell and looks to be one of the best at the current time in this size.



Notes and links

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
Compare to 18650 and other batteries