Overview

The PiJuice HAT is an intelligent hardware Uninterruptible Power Supply (UPS) and battery management HAT engineered by Pi Supply (Nebra) for the Raspberry Pi (compatible with Pi 5, 4B, 3B+, 3A+, Zero, and Zero 2 W).

Equipped with an onboard STM32 microcontroller, a 1820 mAh Motorola BP6X LiPo battery (swappable and expandable to larger LiPo/LiFePO4 cells up to 12,000+ mAh), a hardware Real-Time Clock (RTC), two programmable RGB status LEDs, and a soft power button, the PiJuice HAT ensures continuous 24/7 uptime during AC power outages. It streams battery percentage, charging current, voltage, and temperature telemetry over I2CI^2C (0x14).

Quick reference

Input Power4.2V to 10V DC via Micro-USB / USB-C / Solar Header
Output Power5.2V DC up to 2.5A continuous to Raspberry Pi GPIO 5V rail
Default Battery1820 mAh Motorola BP6X LiPo cell (included)
InterfaceI2CI^2C (0x14 default, software configurable)
Power Management MCUOnboard STM32F030C8T6 32-bit ARM Cortex-M0
Battery Fuel GaugeLC709203F battery capacity fuel gauge IC
Battery Charger ICTI BQ24160 highly-integrated switch-mode charger
Hardware RTCIntegrated Real-Time Clock with alarm wake-up
Solar InputDedicated onboard solar panel charging pads (4.2V–10V)

Pinout (Raspberry Pi 40-Pin GPIO Header Connections)

The PiJuice HAT plugs directly onto the Raspberry Pi 40-pin GPIO header:

PinNameDescription
2, 45V PowerSupplies regulated 5.2V DC power from battery boost converter to Pi
6, 9, 14, 20, 25GNDCommon ground reference
3SDA (GPIO 2)I2CI^2C Data line (0x14 address)
5SCL (GPIO 3)I2CI^2C Clock line
—Micro-USB / USB-CPower charge input on PiJuice PCB
—Solar Terminal2-pin header for 4.2V–10V solar panel input

Specifications

ParameterSymbolMinTypMaxUnitConditions
Charge Input VoltageVinV_{in}4.25.010.0VMicro-USB / Solar input
Regulated Output VoltageVoutV_{out}5.15.25.3VBoost converter to Pi 5V rail
Continuous Output CurrentIoutI_{out}—2.53.0APeak burst output
Included Battery CapacityCapCap—1820—mAhStandard BP6X LiPo cell
Standby Sleep DrawIsleepI_{sleep}—20—µALow power deep sleep
Operating TemperatureToprT_{opr}-20—60°CThermal safety shutdown at 60°C

Soft Power Button & Automated Shutdown Features

  • Soft Power Off: Pressing the onboard power button initiates a graceful OS shutdown script (sudo shutdown -h now) before cutting 5V power to the Pi.
  • Auto-Boot on Power Restoration: When AC mains or solar power returns, the PiJuice automatically powers on the Pi once the battery reaches a configurable charge threshold (e.g. >15%>15\%).
  • Watchdog Timer: Onboard MCU acts as a hardware watchdog timer; if the Pi OS freezes, the PiJuice power-cycles the 5V power rail.

Wiring (Stand-Alone Raspberry Pi Integration)

Simply mount the PiJuice HAT onto the 40-pin GPIO header of any Raspberry Pi model. Connect main USB power to the PiJuice USB port rather than the Raspberry Pi USB port.

Example (Python pijuice Library)

python
import time
from pijuice import PiJuice

# Connect to PiJuice I2C interface (Address 0x14)
pijuice = PiJuice(1, 0x14)

# Query battery status & charge percentage
status = pijuice.status.GetStatus()
charge = pijuice.status.GetChargeLevel()
voltage = pijuice.status.GetBatteryVoltage()
current = pijuice.status.GetBatteryCurrent()

print("--- PiJuice HAT Telemetry ---")
print(f"Battery Charge Level: {charge['data']}%")
print(f"Battery Voltage: {voltage['data']} mV")
print(f"Battery Current: {current['data']} mA")
print(f"Power Input Status: {status['data']['powerInput']}")
print(f"Battery Status: {status['data']['battery']}")

Common mistakes

  • Plugging USB power into the Pi instead of the PiJuice: Connecting the main USB power cable to the Raspberry Pi instead of the PiJuice micro-USB/USB-C port bypasses the charging circuit, leaving the battery uncharged.
  • Using an underpowered USB power brick: Supplying <2.0A<2.0\text{A} from cheap phone chargers prevents the BQ24160 charger from simultaneously powering the Pi and charging the LiPo battery.

Notes

  • PiJuice HAT vs Adafruit PowerBoost 1000C: PiJuice includes an onboard MCU, RTC, I2CI^2C telemetry, software daemon, and Pi 40-pin GPIO header footprint; PowerBoost is a standalone boost/charger breakout PCB.

Assets & downloads