1S BMS 18650 Li-ion Fast Charge Module USB-C PD 18W

Upgrade your DIY power bank or battery project with this compact 1S BMS 18650 Li-ion Fast Charge Module. Measuring just 28 × 28 mm, this thumbnail-sized board packs serious performance — supporting USB-C PD bi-directional fast charging at up to 18W, making it one of the most capable single-cell charge/discharge modules available for makers and electronics enthusiasts.

Key Features

• PD Bi-Directional Fast Charging: Supports both fast charge input and fast discharge output via USB-C
• Max Input/Output Power: 18W
• Max Charge/Discharge Current: Up to 4A
• Battery Charge Cut-off Voltage: 4.2V / 4.35V (selectable)
• Compatible Voltage: 3.7V / 4.2V 1S lithium-ion and lithium polymer cells (e.g. 18650)
• Integrated Charge-Discharge Board: Combines BMS protection, charging, and boost functions in one module
• Compact Form Factor: 28 × 28 mm metal construction — ideal for space-constrained builds
• Available in 2 color options to suit your project aesthetic

Specifications

• Input Voltage: DC 5V (USB)
• Battery Voltage: 3.7V / 4.2V (1S Li-ion / LiPo)
• Fast Charge Protocol: USB Power Delivery (PD)
• Max Current: 4A (input & output)
• Max Power: 18W
• Dimensions: 28 × 28 mm
• Material: Metal

Important Notes

• Ensure connecting wires between the battery and the module are kept short and thick to minimize resistance and heat at high current.
• If using an optional battery protection board, it must sustain a minimum 4A output current to avoid triggering protection cutoff during fast discharge.

Ideal For

• DIY power banks and portable battery packs
• Hobbyist and maker electronics projects
• 18650 cell charging and protection circuits
• Rapid prototyping of USB-C powered devices

For guidance on safe lithium battery handling and electronics safety standards, visit the U.S. Consumer Product Safety Commission – Lithium Battery Safety.

Frequently Asked Questions

Q: What does the 1S BMS 18650 Li-ion Fast Charge Module do?

A: This module is a compact 3.7V/4.2V lithium-ion charge-discharge integrated board. It combines battery management (BMS), USB-C PD fast charging, and boost discharge functions into a single 28 × 28 mm board. It supports up to 4A current and 18W power, making it ideal for DIY power bank builds and portable electronics projects.

Q: Is this module compatible with 18650 batteries?

A: Yes. The module is designed for 1S (single-cell) 3.7V/4.2V lithium-ion and lithium polymer cells, including standard 18650 format batteries. Simply connect your cell to the battery pads on the board following the polarity markings.

Q: What USB fast charge protocol does this module support?

A: The module supports USB Power Delivery (PD) bi-directional fast charging, enabling up to 18W of power for both charging the connected battery and powering output devices via USB-C.

Q: Are there any wiring precautions I should follow?

A: Yes — because the module operates at up to 4A, it is critical to use short, thick wires between the battery and the module. Long or thin wires introduce resistance that can cause voltage drops and excessive heat at high current levels.