USB Smart Battery Charger 1/2/4-Slot – 18650 21700 26650

Keep all your 3.7V lithium batteries topped up and ready to go with this versatile USB Smart Battery Charger. Available in 1, 2, or 4-slot configurations, it charges a wide range of cylindrical lithium-ion cells — from compact 10440s all the way up to large 26650s — making it the only charger you'll ever need for flashlights, fans, vapes, beauty devices, smart thermometers, and more.

Made in Mainland China.

Key Features

• Universal USB Input: Powered via USB (DC 5V / 2A) — plug into any phone charger, power bank, laptop, or USB hub for convenient, low-voltage charging anywhere.
• Wide Battery Compatibility: Telescopic spring contacts accommodate cells of varying lengths — compatible with 10440, 14500, 16340, 16650, 14650, 18350, 18490, 18500, 18650, 21700, 26650, and 26700 lithium batteries.
• Intelligent IC Protection: Built-in smart IC chip automatically stops charging when cells reach full capacity (DC 4.17–4.2V). Also features output short-circuit and reverse-polarity protection for safe, reliable operation.
• Easy LED Indicator: Red LED = charging in progress; Green LED = fully charged or no battery loaded. At-a-glance status, no guesswork needed.
• Durable ABS Housing: Solid black ABS plastic shell built to handle everyday use.
• Compact USB Cable Included: Comes with an approx. 60 cm USB charging cable right in the box.

Technical Specifications

• Input Voltage: DC 5V / 2A (USB)
• Output Voltage: DC 4.2V / 1000mA per slot
• Full Charge Voltage: DC 4.17–4.2V
• Color: Black
• Cable Length: ~60 cm
• Compatible Cells: 10440, 14500, 16340, 16650, 14650, 18350, 18490, 18500, 18650, 21700, 26650, 26700

What's in the Box

• 1 × USB Smart Battery Charger (your choice of 1, 2, or 4-slot)
• 1 × USB Charging Cable (~60 cm)

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For more information on lithium-ion battery safety and handling, visit the U.S. Consumer Product Safety Commission – Lithium-Ion Battery Safety Information.

Note: Due to monitor settings and lighting conditions, the product color in photos may vary slightly from the actual item. Please allow ±3 mm measurement deviation due to manual measurement.

Frequently Asked Questions

Q: Which battery sizes is this USB smart battery charger compatible with?

A: This charger supports a wide range of cylindrical 3.7V lithium-ion batteries, including 10440, 14500, 16340, 16650, 14650, 18350, 18490, 18500, 18650, 21700, 26650, and 26700. The telescopic spring contacts adjust to accommodate different battery lengths automatically.

Q: How do I know when my batteries are fully charged?

A: The built-in LED indicator makes it simple — the red light stays on while charging is in progress, and the green light illuminates once the battery is fully charged (or when no battery is inserted). The intelligent IC also auto-cuts power at full charge to prevent overcharging.

Q: What power source can I use to charge this device?

A: The charger uses a standard USB input (DC 5V / 2A), so you can power it from any USB wall adapter, laptop USB port, power bank, or USB hub — making it ideal for home, office, or travel use.

Q: Is this charger safe to use overnight?

A: Yes. The smart IC automatically stops charging once batteries reach full capacity and includes output short-circuit and reverse-polarity protection. However, as a general best practice for any battery charger, it is advisable to monitor charging sessions and not leave devices unattended for extended periods.