Test/review of Efest IMR20700 3000mAh (Purple) 2017

Efest IMR20700 3000mAh (Purple) 2017

Official specifications:

  • Rated capacity: 3000mAh

  • Nominal voltage: 3.7V

  • Voltage at end of discharging: 2.5V

  • Max. charging current: 4A

  • Standard charge: 2A

  • Discharging current 30A

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

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

  • Inner resistance: 20mOhm

  • Cell size: 20 (±0.20)mm x 70 (±0.2)mm

Efest do also have a battery in one of the new sizes that is slightly larger than 18650. The extra size is used for better high current handling in this cell

The two batteries are not perfectly matched, there is a small difference. The batteries have fairly constant capacity at any current.

At 30A they get very warm and I had to stop shortly before they where empty.


This is a nice high current battery and the slightly large size compare to a 18650 can be seen on the improved performance.
This battery is mostly for people that needs well above 10A, for lower currents look at a 18650.

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