Test/Review of Efest IMR18650 2000mAh (red)

[size=+3]Efest IMR18650 2000mAh (red)[/size]
V1 Flat top



Official specifications:

• Efest IMR 18650
• Brand: Efest Model: 18650 V1
• High Drain battery
• Capacity:2000mah Material: Li-Mn
• Positive Pole: flat top
• Sizes: 18.11(L)*65.02(W)mm

Internal resistance is calculated between 4A and 5A










Acceptable performance up to 7A, but they have problems with 10A.















V2 Button top



Official specifications:

• Nominal Voltage: 3.7v
• Battery Model: 18650v Capacity: 2000mAh
• LiMn High Drain battery
• Positive: Nipple Top
• Cycle Life: 500 Cycles
• Max Charging Rate: 4.5amps
• Sizes: 18.10(L)*66.06(W)mm

Internal resistance is calculated between 4A and 5A










Acceptable performance up to 5A, but they have problems with 7A and 10A.















[size=+3]Conclusion[/size]

These batteries are supposed to be IMR cells, but their performance it not good at high currents.
At 5A and below they do have an acceptable performance.



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

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

I've always had the sneaking suspicion that a lot of these Chinese manufacturers just slap an IMR label on a generic LiCo cell.