The 3-USB Portable Power Bank Circuit is a high-capacity power management module designed for DIY enthusiasts who want to build their own multi-device charging stations. At Electrapac, we recommend this board for projects using multiple 18650 lithium cells in parallel to create a high-performance portable charger.

Product Overview

This module features a sophisticated "All-in-One" design, integrating a Lithium Battery Charger, a Synchronous Boost Converter, and a Digital LCD Status Display. Unlike standard single-port modules, this board provides three USB-A output ports, allowing you to charge a smartphone, a tablet, and a third accessory (like Bluetooth headphones) simultaneously from a single 3.7V battery bank.

Key Features for Electrapac Customers

• Triple Device Charging: Equipped with three independent USB output ports, making it ideal for shared power banks or multi-gadget users.

• Intelligent LCD Display: The backlit screen provides real-time data, showing the Battery Percentage (0-100%) and indicating which output ports are currently active ("OUT") or if the bank is "IN" (charging).

• Smart Power Management: Automatically detects when a device is plugged in to start charging and shuts down after 30 seconds of inactivity to preserve your Electrapac battery life.

• High-Efficiency Boost: Efficiently converts 3.7V battery power to a stable 5V output with minimal heat generation.

• Dual LED Flashlight: Most versions of this board include two small "Torch" LEDs that can be activated by double-clicking the side button—perfect for emergency use.

Wiring & Assembly Guide

To ensure your custom power bank is safe and efficient, follow these steps:

1. Parallel Battery Setup: You can connect 1 to 6 (or more) 18650 cells in Parallel.

   Warning: Never connect batteries in Series (End-to-End). This board is designed for 3.7V input only. High voltage will destroy the IC.

2. Solder Points: Connect the Positive (+) lead of your battery pack to B+ and the Negative (-) lead to B-.

3. Activation: After soldering the batteries for the first time, you must plug a Micro-USB charger into the board to "wake" the protection circuit.

4. Wire Gauge: Use thick copper wire (at least 20 AWG) for the battery connections to handle the current draw without losing power to resistance.

Primary Applications

• High-Capacity DIY Power Banks: Building a 20,000mAh+ portable charger using recycled laptop batteries.

• Camping Power Stations: Creating a multi-port charger for outdoor trips where several people need to charge phones.

• 3D-Printed Charging Hubs: Designing a custom-fit enclosure to match your aesthetic or gear.

• Emergency Preparedness Kits: A reliable way to keep multiple small devices powered during a blackout.

• Hobbyist Testing: A portable 5V source for testing USB-powered sensors and microcontrollers.

Why Shop at Electrapac?

We source our 3-USB Power Bank Boards with high-clarity LCD screens and reinforced USB ports to withstand frequent plugging and unplugging. At www.electrapac.com, we provide the specialized circuitry you need to turn loose batteries into professional-grade tools.