Efest Lithium-Ion Battery Chargers

(Q4 4-Bay • K1 & K2 • Mega USB 2-Bay • Slim K4)

Efest battery chargers are engineered for safe, efficient, and reliable charging across a wide range of lithium-ion batteries. Designed for both everyday users and high-demand applications, Efest chargers deliver consistent performance while protecting battery health and extending overall lifespan.

Compatible with popular battery sizes such as 18650, 20700, and 21700, these chargers feature intelligent charging technology, built-in safety protections, and easy-to-read LED indicators for straightforward battery management. Whether you need a compact single-bay charger or a multi-bay solution for higher volume use, Efest offers a dependable option to keep your devices powered and ready.

Available Models

Q4 Charger – 4-Bay
K1 Charger – Single Bay
K2 Charger – Dual Bay
Mega USB Charger – 2-Bay
Slim K4 Charger – 4-Bay Slim Profile

Key Features

Intelligent Charging System – Automatically detects battery status to deliver optimal charging performance
Multiple Charging Rates – Supports varying charge outputs depending on battery count and model
LED Status Indicators – Displays real-time charging progress for each bay
Built-In Safety Protections – Includes overcharge protection, reverse polarity protection, and temperature monitoring
Wide Battery Compatibility – Designed for common 3.6V / 3.7V lithium-ion IMR batteries
Compact & Practical Design – Ideal for home, shop, or travel use

Battery Compatibility

Compatible with 3.6V / 3.7V Lithium-Ion IMR Batteries, including but not limited to:
10440, 14500, 16340, 17340, 18350, 18490, 18500, 18650, 20700, 21700, 26500, 26650
(Battery compatibility may vary slightly by charger model.)

Technical Specifications

Input: AC 100–240V ~ 50/60Hz or DC 12V
Charging Voltage: 4.2V ± 0.05V
Cutoff Voltage: 4.20V ± 0.05V

Usage & Safety Notes

Use only with compatible lithium-ion batteries.
Always insert batteries with correct polarity.
Do not leave charging batteries unattended.
Do not use damaged batteries or chargers.
Store and operate chargers in a dry, temperature-controlled environment.

Product specifications and packaging may vary by model and are subject to change without notice.

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