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Efest Slim K4 Charger


The newest charger in the K series from Efest.

With 4 battery bays designed to fit a 18650, and USB-C charging capability and auto smart cut off, The Slim K4 is capable of charging at either 1A per channel with 2 batteries or 0.5A using 4 channels.

The smart indicator light lets you know when the cell is in charging status. The indicator turns a solid white colour to alert you the battery has finished the charging cycle.


Please note, 21700 and 20700 will struggle to fit in this device, risking damage to the springs or battery’s themselves.

If you need an Efest charger for larger battery’s then look at the Q2, Q4 and Q8 Lush series of chargers.



  • 18650 Only
  • Input Power – DC 2A
  • Auto Cut Off Voltage – 4.2
  • Activation Current 50ma
  • Operation Temperature 0-40 Degrees Celsius
  • ABS Fire Retardant Construction
  • Springs Tested 15,000 Times For Life
  • 6 Levels Of Safety Protection

Package Contents;

  • 1x Efest Slim K4 Battery Charger
  • 1x Type C Cable
  • 1x User Guide