SCap UPS Board

1. Product Overview

Supercapacitor UPS Module, 5V Output, 5V-24V Input.

This supercapacitor-based uninterruptible power supply (UPS) module is equipped with two supercapacitors, offering long service life and strong discharge capability. The input supports a wide voltage range of 5V to 24V, with multiple input interfaces including a USB Type-C connector, DC barrel jack, and 2-pin screw terminal, making it suitable for various power supply environments.

The output is regulated at 5V, and multiple output interfaces are provided, including a USB Type-A port, 2-pin screw terminal, and 2-pin header, allowing simultaneous power supply for different peripherals. Several onboard status indicators are available, including an input power indicator, output indicator, and supercapacitor voltage indicators.

When an external power supply is connected and the supercapacitors are fully charged, the board can provide a peak output of 5V/5A. When the external power supply is disconnected, the fully charged supercapacitors can independently provide a stable 5V/3A output.

In the event of external power loss, the module can provide approximately 15 to 110 seconds of backup time, depending on the supercapacitor charge level and load current, giving the system enough buffer time for data saving and safe shutdown.

2. Features

• Wide input voltage range: supports 5V-24V input.

• Long cycle life and strong discharge capability with two supercapacitors.

• Peak output up to 5V/5A when external power is connected and the capacitors are fully charged.

• Backup duration of approximately 15-110 seconds during power failure.

• Onboard protections including input reverse-polarity protection and output short-circuit protection.

• Rich status indication with input power LED, output LED, and supercapacitor voltage LEDs.

• Multiple input and output connection options for flexible system integration.

• Compact board size of 85 mm x 56 mm with six M2.5 mounting holes.

3. Specifications

4. Module Resources

1. Type-C connector: used for connecting a power adapter as the input.

2. 3.5 mm 2-pin screw terminal: input terminal, supports 5V-24V input.

3. DC-044 connector: external power input through a DC plug, supports 5V-24V input.

4. Power input indicator LED: lights up when input power is present; turns off when power is disconnected.

5. Supercapacitors.

6. Supercapacitor voltage status LEDs: provide an approximate indication of the current supercapacitor voltage.

7. Output indicator LED.

8. 2-pin 2.54 mm pitch capacitor measurement header: used to measure the voltage of an individual supercapacitor.

9. 2-pin 2.54 mm pitch input detection header: outputs 3.3V when external power is present and 0V when power is lost.

10. 3.5 mm 2-pin screw terminal: 5V output.

11. 2-pin 2.54 mm pitch header: 5V output.

12. USB Type-A connector: 5V output.

13. M2.5 mounting holes.

4. Usage

4.1 Functional Description

4.1.1. Input Power

The board supports 5V-24V input. You can connect a power adapter, DC power cable, or similar power source to the board. When power is connected correctly, the VIN indicator will remain on.

If the power is connected incorrectly, such as reversed polarity, poor contact, or similar issues, the VIN indicator will remain off.

4.1.2. Output Capability

The board can provide up to 5V / 5A output. If the output current exceeds 4A for an extended period, additional cooling is recommended to prevent overheating and abnormal operation.

When external power is connected and the supercapacitors are fully charged, the board can provide a peak output of 5V / 5A. After external power is disconnected, the fully charged supercapacitors can independently provide a stable 5V / 3A output.

4.1.3. Supercapacitor Voltage Indicators

The supercapacitor voltage indicators provide an approximate indication of the current capacitor voltage, as shown below:

Table 4-1 Supercapacitor Voltage Status LEDs

4.1.4. Output Efficiency Under Different Input Conditions

The output efficiency under different input conditions is shown below:

Table 4-2 High-Current Output Efficiency Under Different Input Voltages

For all four test conditions above, the board was continuously loaded for 1 hour. The efficiency data is for reference only. Cable losses, device performance variations, and other factors were not excluded during testing. Actual efficiency depends on real application conditions, load level, and environment.

For temperature rise reference when the board is loaded at 5A under 12V to 5V output and 9V to 5V output, please refer to the corresponding figures in the original wiki material.

Figure 4-1 Board Temperature Rise Reference 1

Figure 4-2 Board Temperature Rise Reference 2

4.1.5. Discharge Time with Fully Charged Supercapacitors

Reference discharge times with fully charged supercapacitors are shown below:

Table 4-3 Supercapacitor Discharge Time

4.1.6. External Power Loss Detection

Taking Raspberry Pi 4B as an example, use the board's 5V output to power the Raspberry Pi 4B, and connect the DetcVIN pin header to the GPIO18 pin of the Raspberry Pi. The DetcVIN header outputs a 3.3V logic level, and the board's GND should also be connected to the Raspberry Pi's GND pin.

The purpose of the reference wiring diagram in the original wiki is to illustrate the connection method between the board and Raspberry Pi when using the external power loss detection function.

Figure 4-3 Reference Diagram for External Power Failure Detection Connection

First, make sure that the RPi.GPIO library is installed on the Raspberry Pi. It is required for GPIO control. Most Raspberry Pi systems have it installed by default. If not, install it using the following commands:

sudo apt update

sudo apt install python3-rpi.gpio

sudo python3 Detc.py

After running the code, when the external power is disconnected and the Raspberry Pi is powered only by the supercapacitors, the Raspberry Pi will execute the corresponding data-saving and shutdown commands.

4.1.7. Supercapacitor Charging Time

The maximum charging current of the supercapacitors is approximately 800mA, and it takes about 4 minutes to fully charge the supercapacitors.

4.2 Precautions for Use

• This supercapacitor UPS is designed to provide short-term backup power for devices such as Raspberry Pi during power failure, ensuring data can be saved and reducing damage caused by sudden power loss during storage read/write operations. However, this UPS does not include power path management, so it cannot automatically restart the system after external power is restored.

• Taking the Raspberry Pi platform as an example, after the user application detects external power loss and the system switches to supercapacitor-only power mode, it should complete data saving and execute a software shutdown.

• To wake up the Raspberry Pi again after software shutdown, there are two methods: perform a reset; or wait until the UPS is fully discharged and enters complete power-off mode, after which the Raspberry Pi will start automatically the next time power is applied.

• Please store the board in a dry environment at normal room temperature, and avoid moisture or high temperature.

• Do not use the supercapacitor module in high-temperature or extremely cold environments, otherwise the performance of the supercapacitors may be affected and backup time may be reduced. Also avoid severe impact or contact with sharp objects to prevent damage to the supercapacitors.

5. Resources

• Schematic

• Demo Codes

• Product

6. Appendix

6.1 Product Notes and Repair

6.1.1 Precautions

• Do not plug or unplug the module while powered on.

• Follow all warning and guidance information marked on the product.

• Keep this product dry. If it is accidentally splashed or soaked by any liquid, immediately disconnect the power and let it dry thoroughly.

• Ensure proper ventilation and heat dissipation during use to avoid component damage caused by excessive temperature.

• Do not use or store this product in dusty or dirty environments.

• Do not use this product in environments with frequent temperature fluctuations between hot and cold, to avoid condensation damage to components.

• Do not handle this product roughly. Dropping, striking, or severe vibration may damage the circuit and components.

• Do not clean this product with organic solvents or corrosive liquids.

• Do not repair or disassemble the product by yourself. If the product malfunctions, please contact the supplier promptly for repair. Unauthorized repair may damage the product, and such damage will not be covered under warranty.