4S PD 100W Buck-Boost Fast-Charging Module 20V 5A Bidirectional

4S PD 100W Bidirectional Fast-Charging Buck-Boost Module – 20V 5A

Take your DIY power bank or energy storage build to the next level with the Gaqqee 4S PD 100W Integrated Charge/Discharge Buck-Boost Module. Delivering a powerful 20V at 5A output and featuring intelligent bidirectional charging, this compact circuit board is engineered for makers, engineers, and electronics enthusiasts who demand high performance and versatility in a single module.

Made in Mainland China.

Key Features

• 100W High-Speed Output: Supports 20V/5A output via Type-C1 for rapid charging of laptops, power banks, and compatible devices.
• Bidirectional Buck-Boost Circuit: Seamlessly handles both charging and discharging of 4S lithium battery packs — ideal for power banks and energy storage systems.
• Multi-Port Design: Features 2× Type-C ports and 2× USB-A ports, each with intelligent device recognition that automatically matches the optimal current and voltage.
• Real-Time Digital Display: Live readout of battery level (%), voltage (V), and current (A) for complete visibility during operation.
• Wide Voltage Compatibility: Supports 5V, 9V, 12V, 15V, and 20V input/output profiles — compatible with virtually any PD-capable charger or device.
• Precise Battery Protection: Voltage matching tailored for 4S lithium battery packs helps extend battery service life and maintain safe operation.
• Low Power Consumption: Efficient design minimises idle draw, maximising effective capacity from your battery pack.

Full Port Specifications

4S Battery Wiring Guide

For a 4S battery pack, connect from the negative terminal up: b1 = 4.2V, b2 = 8.4V, b3 = 12.6V, b+ = 16.8V (positive terminal). Connect the protection board's P+ and P− terminals to the main board's (+) terminal. Always disconnect the power supply before soldering — connect the main board (+) and (−) first, and solder the battery pack's negative terminal last.

Important Setup Notes

• If the device does not light up after connection, charge via the C-port first to activate the module — activation is required regardless of battery charge level.
• After first activation, the display may briefly show 0% or 100%. Battery level calibration normalises after a few charge/discharge cycles.
• Charging stopping at ~80% or discharging cutting off at ~20% typically indicates cell voltage inconsistency — check your battery pack's cell balance.
• This module does not include cell balancing; balancing and protection functions require a separate lithium battery protection board.

Package Contents

• 1× 4S PD 100W Buck-Boost Charge/Discharge Module

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Learn more: EPA guidance on lithium-ion battery handling

Frequently Asked Questions

Q: Is this 4S PD 100W module compatible with LiFePO4 batteries?

A: The default wiring guide is optimised for standard lithium-ion 4S packs (4.2V per cell). LiFePO4 cells operate at 3.6V per cell — please verify voltage thresholds before connecting an LiFePO4 pack to ensure safe and correct operation.

Q: Why does the digital display show incorrect battery levels after first use?

A: On initial power-up, the module's battery level indicator may display 0% or 100% due to calibration. This is normal behaviour — the reading will become accurate after completing a few full charge and discharge cycles.

Q: Can I use both Type-C ports simultaneously for input and output?

A: The module supports independent operation on each port. Type-C1 can deliver up to 100W (20V/5A) output while Type-C2 handles its own profile, but simultaneous dual-port input is not recommended. Always refer to your specific build requirements when configuring multi-port operation.

Q: Does this module include built-in cell balancing for the 4S battery pack?

A: No. Cell balancing and full protection functions are handled by a separate lithium battery protection board, which is not included. An additional BMS (Battery Management System) board is strongly recommended for safe long-term use.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.