Test/review of Efest IMR18650 2100mAh (Purple) 2017

Efest IMR18650 2100mAh (Purple) 2017

Official specifications:

  • Rated capacity: 2100mAh

  • Nominal voltage: 3.7V

  • Voltage at end of discharging: 2.5V

  • Max. charging current: 4A

  • Standard charge: 2A

  • Discharging current 25A

  • Pulse discharging current: 38A

  • Charging temperature range: 0°C ~ 45°C

  • Discharging temperature range: –20°C ~ 75°C

  • Inner resistance: 20mOhm

  • Cell size: 18.50 (±0.20)mm x 65.20 (±0.2)mm

A high current cell with fairly low capacity.

The discharge curves looks very good with tracking and about constant capacity up to 20A.

The cell gets hot at 30A, but not too hot.
I have a suspicion that I did not mount the temperature sensor for the B cell correctly.


The test shows a good quality cell that can deliver lot of current, but the capacity is not very high by todays standard.

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
Compare to 18650 and other batteries

I'd have said this cell to be a Sony VTC4 rewrap but seems a bit better, no overheating at 30A. ¿?

Some LG from the HD series