Efest Slim K2 Battery Charger is a compact, intelligent two-bay charger designed for a wide variety of lithium-ion cells. With LED displays, protective circuitry, and USB power input, it’s ideal for retail shelves and tech accessory bundles.

Key Features

Dual Charging Bays — can charge two batteries simultaneously
USB Input via Micro-USB — powered by 5 V USB sources
1 A Output per Bay — efficient CC/CV charging performance
LED Display Indicators — shows real-time charging status per slot
Safety Protections — including reverse polarity, overcharge, short circuit, and auto cut-off
Wide Battery Compatibility — supports common battery types like 10440, 14500, 16340, 18650, 20700, 21700, 26650, etc.
Auto-Detect / Activation Feature — charger recognizes the battery and begins charging automatically

Specifications

Input: 5 V DC (Micro-USB)
Output: 5 V / 1 A per bay
Auto Cut-Off Voltage: 4.20 V (±0.05 V)
Operating Temperature: 0 °C to 40 °C
Storage Temperature: –40 °C to 70 °C

Wholesale & Retail Benefits

Essential Accessory — every device user needs a battery charger at some point
Compact & Shelf-Friendly — small footprint makes it easy to display or bundle
High Utility — appeals to users of mods, flashlights, power tools, and other battery-powered gear
Accessory Bundling Opportunity — sell with batteries, wraps, and power supplies
Low Return Risk — robust protections reduce failure/scam complaints

Usage & Best Practices

Insert batteries fully until they make secure contact; charger will start automatically
Never charge batteries with damaged wraps or exposed terminals
Do not leave charging unattended for extended hours — remove when fully charged
Use a quality USB cable rated for sufficient current — lower quality cables may limit performance
Store the charger in a cool, dry place when not in use to prolong its life