UPS Scap 5V5A

Safety Instructions & Warnings

① Short-circuiting the positive and negative terminals of the capacitors is strictly prohibited. Damage caused by a short circuit is not covered under warranty.

② Before storing, please press and hold the discharge button to discharge the capacitors.

③ Before disassembling or assembling modules, please turn off the main power switch.

Overview

The UPS_Scap_5V5A is a supercapacitor-based UPS power module designed specifically for the Raspberry Pi 5. It supports either a 12V PD input or a wide-range 9–24V input (use one or the other), and offers three output options: PD USB-C, USB-A, and pins, with a total output of up to 5V 5A. The USB-C port supports the 5V 5A PD protocol required by the Raspberry Pi 5.

The 100F supercapacitor provides ample power for extended battery life. It features a main power switch and bleed circuitry, and can be mounted on the bottom of the Raspberry Pi for power via header pins or a USB-C to USB-C connector. A power monitoring circuitry allows for reading the supercapacitor's voltage and charging/discharging current via an I2C interface to estimate battery life. A compatible USB-C adapter allows for direct stacking on the bottom of the Raspberry Pi 5.

Features

• Raspberry Pi 5 Dedicated PD Handshake Power Supply: Natively compatible with the Raspberry Pi 5's non-standard 5V5A PD power supply protocol, avoiding the "insufficient power" pop-up alarm triggered by ordinary power supplies; the included USB-C adapter board can be directly stacked on the bottom of the Raspberry Pi 5 for plug-and-play functionality.

• 100F High-Capacity Supercapacitor Power-Off Protection: In long-run mode, it can provide up to 3 minutes and 31 seconds of continuous use under a 5V 0.5A load, allowing ample time for data writing and safe system shutdown; the supercapacitor solution eliminates the safety hazards of lithium batteries, offering long lifespan and maintenance-free operation.

• Dual Input Compatibility for Multiple Scenarios: Supports DC 9-24V wide voltage input / USB-C 12V PD fast charging input (choose one; USB-C requires a ≥30W PD/QC charger); internal dual-path isolation circuitry allows for seamless switching between charging and discharging.

• Multi-interface 5V5A output: Standard configuration includes two outputs: USB-C (with PD handshake) and USB-A, sharing a total 5A power output; additionally, there are reserved unsoldered power supply pads for the top pins. Compatible with Raspberry Pi 3B/4B/5, Orange Pi, and other 5V development boards, and can also power other 5V devices.

• Hardware-level power-down detection and intelligent power on/off: GPIO26 hardware direct connection detects power loss; onboard microcontroller manages the power-on signal, automatically powering on when power is restored from a power-off state; the accompanying official demo script supports automatically clearing the power-on pop-up window to avoid forced shutdown triggered by consecutive power losses, suitable for remote unattended operation scenarios (script needs to be deployed manually).

• I2C real-time voltage and current monitoring: Onboard INA219 chip, reading capacitor voltage and charging/discharging current via the I2C interface for easy estimation of remaining battery life; official support scripts are provided for both Raspberry Pi OS and Ubuntu dual-system compatibility.

• Comprehensive safety design: Integrated main power switch, fast discharge button, 5-level power indicator light, automatic cut-off when capacitor charging reaches 5.2V to prevent overcharge, making operation and storage safer.

Technical Specification

Power input	DC 9-24V wide voltage input, DC 5.5-2.1 interface; USB-C PD interface, PD negotiated voltage 12V, please be sure to use PD or QC power supply; input power recommended ≥30W; (Choose one of the two interfaces) Power input is split into two paths: One path steps down to 5.2V to directly power the target board; The other path charges the supercapacitor. For safety, charging stops after reaching 5.2V. These two paths are isolated by a circuit, therefore they will not output simultaneously.
Output	5V5A output, using high-efficiency boost and buck DC-DC power chips; Dual interfaces: USB-C and USB-A, both sharing 5V5A; Specifically designed for powering Raspberry Pi 5; USB-C features PD handshake negotiation, enabling the 5V5APD handshake protocol for Raspberry Pi 5; USB-A; Both interfaces can also be used to connect to other development boards such as Raspberry Pi 4B/3B/Orange Pi;
Energy storage unit	100F supercapacitor (series structure, maximum fully charged voltage 5.4V, safe charging cut-off voltage 5.2V)
Charging time	Approximately 15 minutes to fully charge (under 30W PD power supply conditions)
Current and Voltage Detection'	Identifies charging and discharging status; voltage and current of the supercapacitor can be read via I2C interface, and the direction of the current indicates whether it is charging or discharging; I2C interface allows reading capacitor voltage and charging/discharging current.
Power-down detection	One power-down detection pin; a logic level of 3.3V indicates the presence of external power input, and a logic level of 0V indicates that the external power is off. For Raspberry Pi, external power loss can be detected via GPIO26 (40-pin); for other development boards, it can be connected to a GPIO pin.
Wake-up function	Power-off self-start circuit (Raspberry Pi 5 exclusive).
Physical Switches	Main power switch + quick discharge button; One power switch to shut off output for safe module installation and removal; One discharge button for quick discharge and safe storage; for example, after use, it is recommended to press this button to discharge the supercapacitor for safety.
Status Indicators	1 power indicator + 5 battery indicator lights + 1 discharge indicator light
Product dimensions	85×56mm; Operating
⚠️ Safety Warning	Due to their high energy density and low internal resistance, supercapacitors must not be short-circuited when powered on; similarly,the positive and negative terminals of two supercapacitors must not be short-circuited. Damage caused by short circuits is not covered under warranty. Please exercise extreme caution during operation.

Packing List

• Supercapacitor UPS 5V 5A PD power module x 1
• USB C-C adapter board x 4

Battery life

After an external power failure, the system automatically switches to supercapacitor power to save data and shut down the system. The measured operating time of the supercapacitor UPS at various cutoff voltages is listed below:

(Note: The three modes—long-run mode, balanced mode, and performance mode—are adjusted by resistors on the circuit board. The factory default is long-run mode.)

100F version: Discharge begins at 5.2V:

Related Explanation

1.PD Handshake Protocol

• The Raspberry Pi 5 uses a non-standard PD handshake protocol. Even if a standard 5V 5A power supply is used and the voltage and current meet the requirements, the system will still issue an alarm if the corresponding handshake protocol is missing.
• This module's USB-C output natively integrates a PD handshake chip, ensuring perfect compatibility with the Raspberry Pi 5 and eliminating pop-up alarms.
• The USB-A port can be used with a USB A-C PD adapter to provide a second power source for the Raspberry Pi 5.

2.Power-Off Detection and Power-On/Off Logic

• Detection Method: Raspberry Pi 5 detects the external power status in real time via GPIO26 pin.

• Power-Off Trigger: GPIO level goes low → Script execution saves data → Countdown → Safe shutdown

• Power-On Sequence (Onboard Microcontroller Power Management): When external power is restored, the module sends a power-on signal to Raspberry Pi 5 via a pin, in two scenarios:

1. System is completely powered off: Automatic power-on upon receiving the signal;
2. System is still running normally: A power confirmation pop-up appears. The application must automatically clear the pop-up. If the pop-up is not cleared after two consecutive power outages and power-on cycles, a forced shutdown will be triggered.

• Dead Zone Special Condition (Extremely Low Probability): After sending the shutdown command, the screen will briefly display plymouth-poweroff.service (lasting approximately 1-2 seconds). If external power is restored during this window, the system will lock and cannot start, only recovering after the next power outage and power-on cycle. Dead zones are extremely rare, so there's no need to worry about them for local use; however,thorough testing and evaluation are recommended for remote, unattended scenarios.

3.I2C Voltage and Current Monitoring

• Real-time I2C bus reading via the INA219 chip: capacitor voltage, charging/discharging current, and power; remaining battery life can be estimated based on voltage.
• Supports Raspberry Pi OS and Ubuntu systems.

4.Power-Down Detection GPIO Script Demonstration

The board has an onboard power-down detection circuit. For a Raspberry Pi 5, it's directly connected to GPIO26 of the 40-pin GPIO for detection. See below for specific instructions (using a Raspberry Pi system as an example; the I2C interface needs to be enabled beforehand). The script code is as follows (script name: gpiot.sh): Power-Down Indication Script Demonstration

5.This module can also be used on non-Raspberry Pi 5 platforms, but please note the following:

1. Power-down detection: Connect the detection signal through the appropriate GPIO pin and read the voltage and current via I2C to determine the charging and discharging status.

1. Power-on/off logic: Most development boards do not have dedicated power-on/off logic for Raspberry Pi 5. After power-off, the system may enter a locked state upon power restoration.

1. Recommended solution: After saving the data, the application continuously monitors the power-down detection pin. If power is restored, the application continues to execute the business process; if power is not restored, it will idle and wait for the system to shut down due to power failure.

1. Compatibility prerequisites: If the target board has a logic power-on/off pin, it can be connected to implement the same automatic power-on/off function as Raspberry Pi 5.