Efest Slim K1 | Single Battery Charger

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Efest Slim K1 is a professional portable one slot Li-ion battery charger with micro USB charging port. Safe and durable & High quality.

Supports any 3.6V/3.7V Lithium Batteries. Fast charging current 1x 1.0A

  • SLIM K1 Charger Body 
  • USB Cable 
  • Operation Manual 
  • Warranty Card 
  • Portable, Easy to Carry 
  • Reverse Polarity Protection 
  • Short-Circuit Protection 
  • Activation Recovery Function 
  • Stops Charging Automatically 
  • AC Input Power: AC 100 - 240V 50/60Hz
  • DC Output Power: DC 5V 1A
  • Auto Cut-Off Voltage: 4.20 (+/= 0.05V)
  • Standby Current: <20mA
  • Auto Recharge Voltage: 4.10(+/= 0.10V)
  • Storage Temperature: -40℃ - +70℃ 
  • DC Input Power: DC 5V 1A
  • 1A CC Current: 1000mA (+/= 10%)
  • CV Cut-off Current <100mA
  • Activation Current: 50mA - 100 mA
  • Operation Temperature: 0℃ - 40℃  


  • Made with Piano springs, provides a smooth sliding action when installing and removing batteries
  • 15,000+ times Spring Testing Quality Warranty 
  • Convient LED Indicator 
  • Steel cathode with low resistance and hard chromium plating processing to achieve a more precise charging voltage 
  • Fire Retardant Shell 
  • Quality Certification



  • 20700
  • 18650
  • 18350
  • 16340
  • 10440
  • 26650
  • 18500
  • 17340
  • 14500
  • 26500


  1. Please connect the AC cable to the AC port first then plug to the power source 
  2. Please check the battery specification before charging for compatibility with K1. If not used correctly, it may cause damage to the battery or the charger. 
  3. Do not charge the battery if the battery’s wrapper is damaged to prevent explosion, leakage or fire, otherwise it will burn the charger. 
  4. Do not use the K1 in flammable or explosive environment. 
  5. Please use K1 in a dry environment 
  6. Please take out the battery and unplug the AC cable while the K1 is not in use. 
  7. Keep out of use of children 
  8. Any scrapped K1 please comply with the local regulatory processes for recycling and disposal 
  9. Please clean K1 regularly to maintain the cleanness of the positive and negative contact to deter foreign objects and prevent poor contact. 
  10. Misusing or mishandling chargers can pose a SERIOUS RISK to personal injury, property damage or death.