Efest Slim K1 one-bay charger with an Efest battery, its box and USB cable

Graveyard Clearance

EFEST Slim K1 Single Battery Charger

Name: Vape Society Supply
Price range: $$

Brand: Efest

Original price was: $11.99.Current price is: $5.99.

Graveyard Clearance price, already marked down. While supplies last.

The EFEST Slim K1 Single Battery Charger is a one-bay USB charger for 3.6V and 3.7V Li-ion and IMR batteries, including 18650s and 21700s, at 1A.

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Description

EFEST Slim K1 Single Battery Charger Review

The EFEST Slim K1 Single Battery Charger is a one-bay USB charger for 3.6V and 3.7V Li-ion and IMR batteries, including 18650s and 21700s. It charges at 1A from a 5V 1A USB input and stops at 4.2V. See more from Efest or browse all battery chargers.

Slim K1 Highlights

1A Charging

Efest rates the charge current at 1A, from a 5V 1A USB input.

Automatic Charging

It detects the battery, charges it with CC and CV charging and stops at 4.2V.

Low-Voltage Activation

Efest lists an activation function that wakes over-discharged batteries at 50mA to 100mA before normal charging.

Built-In Protection

Efest lists reverse polarity, short-circuit and over-charge protection.

Slim K1 Specs

Charging

Bays: 1
Batteries: 3.6V and 3.7V Li-ion and IMR
Charge voltage: 4.2V
Charge current: 1A
Charging mode: CC and CV, with automatic detection

Battery Sizes

Li-ion, IMR: 12 sizes from 10440 to 26650, such as 14500, 16340, 18350, 18650, 20700, 21700 and 26650

K1 Charger

Input: USB, 5V 1A
Display: an LED charge indicator on the end
Protection: reverse polarity, short circuit and over-charge, with low-voltage activation

Batteries

Charge only rechargeable 3.6V or 3.7V Li-ion and IMR batteries, never NiMH, alkaline or other single-use cells, and don’t leave the charger unattended while it’s plugged in.

How to Use the Slim K1

Plug it in: connect the USB cable from the box to the charger and a USB adapter.
Load the battery: insert it with its ends matching the + and − marks. The K1 detects it and starts charging.
Take it out when full: charging stops at 4.2V, and the indicator shows the battery’s status.

Who the K1 Charger Is For

It suits vapers with a single-battery mod who want a small USB charger to carry for 18650 or 21700 batteries. For two bays, see the Slim K2.

Good to know: No wall adapter comes in the box. It comes with a USB cable for your own adapter.

What’s in the Slim K1 Box

Efest Slim K1 charger
USB charging cable
User manual

FAQ

Efest Slim K1 FAQ

Does it charge 21700 batteries?

Yes. Efest lists 21700 and 20700 batteries, along with 18650s and 26650s. We sell IMREN 21700 batteries in 2-packs.

How fast does it charge?

At 1A. Efest rates the input at 5V 1A.

Does it come with a wall adapter?

No. It comes with a USB cable, so plug it into a USB adapter.

Can it charge AA or NiMH batteries?

No. Efest lists 3.6V and 3.7V lithium batteries only.

Which battery sizes fit?

Efest lists 12 sizes from 10440 to 26650, including 16340, 18350, 18650, 20700 and 21700.

How is it different from the Slim K2?

The Slim K2 has two bays, each rated at 1A, so it charges two batteries at once.