EFEST Slim K4 USB-C 4 Bay Battery Charger

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EFEST Slim K4 USB-C 4 Bay Battery Charger

Compatible with Lithium IMR 3.6V/3.7V Batteries: 10440 / 14500 / 16340 / 17340 / 18350 / 18490 / 18500 / 18650 / 26500 / 26650 / 20700 / 21700

Cost effective and easy to use, the Slim K4 charger comes with a user manual and packaging with instructions in 7 different languages. Incredibly lightweight and conveniently portable!


  • Input Power ------------ DC 5V 2A
  • 2*1A CC current ------------ 2000mA±10%
  • 1*1A CC current ------------ 1000mA±10%
  • 4*0.5A / 3*0.5A CC current ------------ 500mA±10%
  • Auto cut-off voltage ------------ 4.20V±0.05V
  • CV cut-off current ------------ <100mA
  • Standby Current ------------ <20mA
  • Activation Current ------------ 50mA~100mA
  • Auto recharge voltage ------------ 4.10±0.10V
  • Operation Temperature ------------ 0°C~40°C
  • Storage Temperature ------------ -40°C±70°C

LED INDICATOR DESCRIPTION - After inserting the battery into the slot correctly, the Slim K4 will start charging the battery automatically within a few seconds. The LED indicator lights will show white while the battery is charging and change to blue once fully charged. 

HIGH QUALITY CRAFTSMANSHIP: Spring made by piano wire, it provides a smooth sliding action when installing and removing batteries. Steel cathode with low resistance and hard chromium plating processing to achieve a more precise charging voltage. 15,000 + times spring testing quality warranty.

USB PORT DESIGN - The Type-C USB port reduces the heat of the port effectively.

Note: There is always an inherent risk when using any rechargeable batteries at anytime and under any circumstances. Myvpro.com and any of Myvpro.com’s parent and subsidiary companies are not held responsible for any damage for any modification of the batteries, chargers, devices and other products that we carry in any form or shape, this is including pack making.


  • 1x EFEST SLIM K4 Charger
  • 1x User Manual

Myvpro.com and any or all of Myvpro.com’s parent and subsidiary companies will not be held responsible or liable for any injury, damage, or defect, permanent or temporary that may be caused by the improper use of a Li-ion (Lithium-ion), LiPo (Lithium-ion Polymer) and any rechargeable battery/batteries as well as chargers. Please have a greater understanding of the batteries/chargers you are using and how to care for them properly.

When working with Li-ion (Lithium-ion), LiPo (Lithium-ion Polymer) and any rechargeable cells, please be cautious and carefully use as they are very sensitive to charging characteristics and may explode or burn if mishandled. Please make sure that you have great knowledge on all rechargeable batteries before you use them. Always charge batteries at the clean and fire-proof surface. Never leave charging batteries unattended. If you see that there are visible damages on the batteries, please do not use. Always keep, store and transport the rechargeable cells in a safe, non-conductive container in controlled environment.

Do not use any rechargeable battery as well as any battery charger if any visible damage is present, as well as if the cell or charger has been stressed through mishandling, accidental or otherwise, even if damage may not be visible. Always store and transport rechargeable cells in a safe, non-conductive container in a controlled environment. Please dispose battery cells, chargers or any other electronic devices in accordance of local laws and mandates.