3x18650 DIY Power Bank Case — Dual USB Fast Charge with LED Night Light

Build Your Own Power Bank.

This 3x18650 battery charger case lets you build a custom power bank using standard 18650 lithium cells — the same cells used in laptops, flashlights, and power tools. Load it with three 18650 batteries and you have a portable dual-USB charger that you can refill with fresh cells when they wear out, rather than replacing the entire unit. The built-in LED night light adds a practical bonus for bedside or camping use.

Features

• 3x18650 cell capacity — holds three standard 18650 lithium cells; total capacity depends on the cells used (typically 6000–12000mAh with quality cells)
• Dual USB-A output at 5V/2A — fast charges two devices simultaneously from the installed cells
• LED night light — built-in LED provides soft ambient light for bedside, camping, or emergency use
• Replaceable cells — when cells wear out, replace them individually rather than discarding the entire unit
• Compact shell — lightweight housing keeps cells organized and protected
• Wide cell compatibility — fits standard 18650 cells (check variant for flat top vs. button top compatibility)

Who It’s For

• DIY electronics enthusiasts who want to build a custom power bank
• Flashlight hobbyists who already stock 18650 cells and want a dual-purpose charger/power bank
• Campers who want a power bank with a built-in night light
• Anyone who wants a long-term, sustainable portable charging solution with replaceable cells

How to Use

1. Insert three fully charged 18650 cells into the case, observing correct polarity (+ and − markings).
2. Close the case and connect devices to the dual USB-A output ports.
3. Press the LED button to activate the night light function.
4. When cells are depleted, remove and recharge using a dedicated 18650 charger, then reinstall.

Frequently Asked Questions

Are 18650 cells included?
No — 18650 cells are not included. Purchase quality cells from reputable brands (Samsung, LG, Panasonic, Sony) for best performance and safety. Avoid unbranded cells with inflated capacity claims.

Can I charge the cells while they’re in the case?
This case requires removing cells for charging in a dedicated 18650 charger — it does not have a USB input for in-case charging. Check the variant details to confirm.

What capacity will I get?
Three 3000mAh 18650 cells provide approximately 9000mAh at 3.7V, which translates to roughly 5000–6000mAh of usable output at 5V USB after conversion losses.