UltraFire UF26650 5000mAh (Flame)



Official specifications:

• Brand: UltraFire
• Color :Black + red
• Type :Lithium Ion
• Model :26650
• Mark Capacity :5000mAh
• Actual Capacity :4000mAh
• Battery Voltage: 3.7V V
• Rechargeable: Yes
• PCB Protected Board :No
• Application :Power supply
• Working voltage: 3.7V
• Charging limited voltage: 4.20+/-0.02V
• Standard voltage: 4.2V
• Discharge cut off voltage: 3.00V
• Charging Current: 0.02 C5A (80mAh)
• Standard charging: 0.5 C5A (2000mAh)
• Standard discharge: 0.5 C5A (2000mAh)
• Quick charging current: 1 C5A (4000mAh)
• Max continual discharge current: 1 C5A (4000mAh)
• Operating Temperature: charge: 0°C~45°C; Discharge: -20°C~60°C

These batteries are protected 26650 and the limit is rather low for the size.











The two batteries tracks very fine.







It looks like the protection on the B battery trips just before the 5A trace is finished.
The reason the voltage increases, is due to a chain of events: First the protection disconnects the battery, because the voltage now is below the minimum voltage my load disconnects, without any load the protection in the battery reconnects, the voltage is now higher because it is unloaded, I measure the voltage and stops the discharge cycle (All this happens in less than 1 second).









Conclusion

These batteries has a good performance for cheap batteries, except for the "low" current limit I do not have anything to complain about.


Notes and links

The batteries was supplied by LightCastle 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