5V Dual USB 8x18650 Battery Box DIY Power Bank Case for Mobile Devices

5V Dual USB 8×18650 Battery Box — DIY Power Bank Case for Mobile Devices

A DIY power bank enclosure designed to hold 8 standard 18650 lithium-ion cells in a 4S2P or 8P configuration, with a built-in boost converter providing 5V dual USB output for charging smartphones, tablets, and other USB-powered devices. The case includes the boost converter PCB, USB output ports, power switch, and LED charge indicator. 18650 cells are not included — use quality 18650 cells (Samsung 25R, LG HG2, Panasonic NCR18650B, or equivalent) for best performance and safety.

Technical Specifications

Parameter	Value
Cell Format	18650 (8 cells)
Cell Configuration	4S2P or 8P (check variant)
Output Voltage	5V DC (regulated)
Output Ports	2 × USB Type-A
Output Current	Up to 2A per port (check variant)
Converter Type	Boost (step-up) converter
Indicator	LED charge level indicator
Switch	Power on/off switch
Batteries Included	No (18650 cells sold separately)
Certification	RoHS

Capacity Reference (8 × 18650 Cells)

Cell Capacity	Configuration	Total Capacity	Estimated Phone Charges
2500mAh (e.g., Samsung 25R)	8P at 3.7V	20000mAh	~5–6 charges (3500mAh phone)
3000mAh (e.g., LG HG2)	8P at 3.7V	24000mAh	~6–7 charges
3400mAh (e.g., Panasonic NCR)	8P at 3.7V	27200mAh	~7–8 charges

Typical Applications

• DIY Power Bank: Build a high-capacity portable power bank using recycled or new 18650 cells for smartphone, tablet, and USB device charging
• Camping & Off-Grid: Large-capacity portable power supply for camping, hiking, and off-grid use where mains charging is unavailable
• Emergency Power: Emergency backup power supply for smartphones and essential electronics during power outages
• Maker Projects: High-capacity 5V power supply for Raspberry Pi, Arduino, and other maker projects requiring extended battery runtime

Safety Notes

• Use only quality 18650 cells from reputable manufacturers (Samsung, LG, Panasonic, Sony)
• Do not mix cells of different brands, capacities, or charge states
• This case does not include a BMS (Battery Management System) — add an external BMS for overcharge, over-discharge, and short circuit protection
• Do not leave charging unattended

Package Contents

• 1 × 8×18650 DIY power bank case with boost converter PCB and dual USB output (batteries not included)

Enjoy free standard shipping on all orders over $199 USD. Orders are processed within 1–2 business days.

Not satisfied? Return any item within 90 days of purchase for a full refund or exchange. Items must be in original condition.

We are committed to quality, reliability, and customer satisfaction. Every product is carefully selected and tested to meet the highest standards.