Keeppower 16650 2500mAh (Black) 2015



Official specifications:

• Capacity min.: 2400mAh
• Capacity typ.: 2500mAh
• Nominal voltage: 3.70V
• Charge voltage: 4.35+/-0.05V
• Standard discharge cut-off voltage: 3.00V
• Standard charge current: 1000mA
• Charge termination current: 50mA
• Standard discharge current: 2400mA
• Max. continuous discharge current: 6A

This is a slimline version of the xx650 battery, it can usual replace two CR123 cells. It has a lower voltage, but more capacity.











The discharge curves looks very good, but the capacity is rather low. The low capacity was expected, the problem is the protection circuit, it terminates before the battery is full!













Look at the voltage drop when charging terminates, it is way to large because of the protection circuit.



Charging with 4.30 volt



Lets try a slightly lower charge voltage.



The batteries has more capacity at this voltage and the discharge curves looks good.













No big drop when charging terminates, this time the protection did not trigger.



Charging with 4.20 volt



What about using a normal LiIon charger?



It is about 200mAh less than 4.30V charging.















Conclusion

It would have been nice with a protection circuit for 4.35V, but even with the capacity loss the battery is a good and a very good substitute for CR123 in lights that can handle the lower voltage.



Notes and links

The batteries was supplied by Keeppower 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
Compare to 18650 and other batteries