DC 5v 2.1A 3.7V Lithium 18650 Mobile Power

A complete single 18650 lithium battery power bank module — charging at 1 A via Micro USB and discharging at 2.1 A via USB-A output at 5 V. With built-in charge management and boost regulation, it's a self-contained DIY power bank core that needs only an 18650 cell and an enclosure to become a functional portable charger.

🔹 Key Applications

• DIY phone and device power bank builds
• Portable project power supply using 18650 cells
• Rechargeable embedded project power source
• Camping and outdoor electronics power
• Emergency USB backup charger builds

🔹 Why Choose This Module?

• 2.1 A USB output — charges phones and tablets at full speed
• 1 A charging input via Micro USB
• Built-in 18650 charge management — protects and charges the cell
• 5 V boost output — stable even as battery depletes
• All-in-one module — just add an 18650 cell and a case

🔹 Technical Specifications

• Input: Micro USB 5 V / 1 A
• Battery: 1 × 18650 (3.7 V, not included)
• Output: USB-A 5 V / 2.1 A
• Protection: Overcharge, over-discharge, short-circuit

🔹 What's Included

1 × 18650 Power Bank Module (18650 cell not included)

🔹 Pro Tip

💡 Use a quality 18650 cell (genuine Samsung 25R, LG HG2, or similar) rated at ≥2500 mAh for best capacity. Avoid unbranded cells — they rarely deliver rated capacity. For a polished build, 3D print or purchase an 18650 case to house the module and cell together.

⚠️ Note: Always ensure proper heat dissipation and correct voltage configuration before powering connected devices.