Efest IMR18650 2000mAh (red)
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.















Conclusion

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.



Notes and links

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