Overview

The UPS HAT (E) is a high-performance uninterruptible power supply (UPS) expansion board designed for Raspberry Pi models, including Raspberry Pi 5, 4B, and 3B+. It ensures continuous operation during power interruptions by providing a stable 5V 6A output, powered by up to four 21700 lithium batteries. The board features a USB Type-C interface for bi-directional fast charging, pogo pin connectors for seamless integration, and real-time monitoring capabilities via I2C. This article provides a detailed technical overview of the UPS HAT (E), its features, specifications, and best practices for optimal use.

Key Features

  • Pogo Pin Connector: Enables solder-free connection to Raspberry Pi, preserving GPIO resources and ensuring compatibility with Raspberry Pi 5, 4B, and 3B+.

  • Bi-Directional USB Type-C Charging: Supports multiple input/output protocols (e.g., PD3.0) with up to 40W charging power, allowing simultaneous battery charging and Raspberry Pi powering.

  • Battery Support: Accommodates 4× 21700 lithium batteries (not included) for extended runtime, up to 20 hours depending on usage and configuration.

  • Real-Time Monitoring: Utilises I2C communication to monitor Type-C port and battery parameters (voltage, current, power, and remaining capacity).

  • Battery Fuel Gauge IC: Provides accurate battery status, enabling low-battery warnings and safe shutdowns to prevent data loss.

  • High-Power Output: Delivers stable 5V 6A output, with a maximum capacity of 10A (active cooling recommended for currents above 6A).

  • Onboard MCU Management: Supports automatic power source detection, system booting, and battery level display within the Raspberry Pi OS.

  • Warning Indicators: Alerts for incorrect battery connections to prevent damage to the protection circuit.

Specifications

  • Control Bus: I2C

  • Battery Support: 4× 21700 lithium batteries

  • Power Input/Output: USB Type-C with bi-directional fast charging (supports 5V, 9V, 12V, 15V, 20V; up to 40W)

  • Output Power: 5V 6A (up to 10A with active cooling)

  • USB Type-A Output: 5V for powering additional peripherals

  • Dimensions: 56 × 88 mm

  • Mounting Hole Size: 3.0 mm

Installation and Setup

Battery Installation

  1. Battery Order: Install 21700 lithium batteries in the sequence V1-V2-V3-V4 to avoid triggering the warning indicator due to reverse polarity.

  2. Reverse Polarity Warning: Do not charge the board if batteries are connected incorrectly, as this may damage the battery protection chip. If the warning indicator lights up, disconnect the charger immediately.

  3. Battery Activation: After installing or replacing batteries, connect the board to a charger to activate the output. Perform several full charge/discharge cycles to calibrate the battery fuel gauge IC for accurate capacity readings.

Hardware Setup

  1. Mounting: Secure the UPS HAT (E) to the Raspberry Pi using the provided screws and acrylic protection panel.

  2. Pogo Pin Connection: Align the pogo pins with the Raspberry Pi’s power pads for a secure, solder-free connection.

  3. Power Connection: Connect a USB Type-C power source (e.g., Raspberry Pi 5 Official 27W USB-C power supply, not included) to the Type-C port for charging and powering.

Software Configuration

  • I2C Monitoring: Enable I2C on the Raspberry Pi via raspi-config to monitor battery and Type-C port status.

  • Battery Level Display: Use provided development resources (available online) to integrate battery status display into the Raspberry Pi OS.

  • Safe Shutdown: Configure scripts to monitor battery voltage via I2C and initiate a safe shutdown when the voltage drops below a safe threshold.

Operational Guidelines

  • Power Management: The UPS HAT (E) automatically switches to battery power during external power interruptions, ensuring uninterrupted operation.

  • Charging Protocols: Supports fast charging protocols (e.g., PD3.0) for efficient battery charging. Ensure the power source supports 5V, 9V, 12V, 15V, or 20V input.

  • Current Limitations: For sustained operation above 6A, implement active cooling (e.g., a fan) to manage heat dissipation.

  • Battery Calibration: Due to variations in battery type and temperature, capacity readings may be inaccurate initially. Rely on voltage values to determine charge status and perform multiple charge/discharge cycles for calibration.

  • Automatic Reboot: The onboard MCU detects power restoration and automatically reboots the Raspberry Pi.

Safety and Precautions

  • Battery Polarity: Incorrect battery installation may activate the warning indicator and damage the protection circuit. Always follow the V1-V2-V3-V4 sequence.

  • Charger Compatibility: Use a compatible USB Type-C charger supporting fast charging protocols to avoid overloading or damaging the board.

  • Low Battery Handling: Configure the system to save files and shut down gracefully when low battery levels are detected to prevent data loss.

  • Heat Management: Avoid prolonged operation at 10A without active cooling to prevent overheating.

Packing List

With Battery Version

  • 1× UPS HAT (E) for Raspberry Pi - 5V 6A Output

  • 1× Acrylic protection panel

  • 1× Screws pack

  • 4× 21700 lithium batteries

Without Battery Version

  • 1× UPS HAT (E) for Raspberry Pi - 5V 6A Output

  • 1× Acrylic protection panel

  • 1× Screws pack

Applications

The UPS HAT (E) is ideal for Raspberry Pi projects requiring reliable power, such as:

  • IoT devices and home automation systems

  • Portable computing setups

  • Remote monitoring stations

  • Embedded systems requiring continuous operation

Resources

  • Official Documentation: https://www.waveshare.com/wiki/UPS_HAT_(E)

Conclusion

The UPS HAT (E) is a robust and versatile power solution for Raspberry Pi, offering seamless integration, high power output, and advanced monitoring capabilities. By following proper installation and configuration steps, users can ensure reliable, uninterrupted operation for their Raspberry Pi projects.