qUPS-P-SC – a Raspberry UPS HAT with supercapacitor

The long-lasting, maintenance free and environmentally friendly UPS solution for Raspberry Pi with wide operating temperature range.

Goal – What we wanted

Create a UPS solution for Raspberry Pi or compatible product, which is durable, has low carbon footprint, and can be used in harsch environment.
As the battery is the bottleneck of the tradional UPS solutions for these requirements, we have chosen SuperCapacitor for energy storage. It has extra high charge cycle rate, and wide operational temperature range. It is much greener product.

Raspberry UPS HAT with Supercapacitor

Design Considerations – how we were thinking

  • From Factor

    For easy assembly, qUPS has HAT form factor. Simply connect it via the 40 pin header.

  • Supercapacity

    Supercapacitors offer superior durability and operate reliably across extended temperature ranges. They also boast significant energy storage capacity in a small footprint.

  • High Efficiency

    For increasing the limited backup time, we have chosen a high efficiency boost solution for feeding the Raspberry Pi.

  • Minimize inline energy loss

    Offline topology is very efficient in inline state, but if the input power is down, system has a very short power loss (< 1ms). Raspberry Pi is sensing it, but there is no effect on its operation.

  • Stackability

    Pins on the connector are long ones, all can be accessed from the top of the product.

  • Communication Capability

    Capable of warning the Raspberry Pi, for having enough time to shutdown itself safely, avoid any crash of the operating system. It happens, when the main power is off, and when the energy level of the system is getting critical.

  • GPIO communication

    Programming is easy for beginners. In most of the cases I2C limitation is the bus capacitance, avoid an extra load on it. There are lot of GPIO ports on the header, and there are 3 options to choose from.

  • Disable communication

    All GPIO ports can be used for other purpose.

  • Reliable connection

    Massive, soldered pin header for power and signal connection. Pogo pins are not reliable.

  • Zero firmware

    Everything is done by hardware.

  • Shutdown issue handling

    If the power is coming back, when the Raspberry is already in shutdown mode, it can stuck in this state. qUPS is able to handle this situation properly.

  • Safe boot

    If there is power outage when the energy level of the supercapacitor is very low, the Raspberry Pi has not enough time to boot and shutdown properly. In AUTO mode it won’t be powered if energy level is low. This level is adjustable.

  • Avoid restart cycle

    If the qUPS’s energy level is too low in backup mode, it can’t power the system. Without a load, it restores 5V, causing the system to restart repeatedly. In AUTO mode, the qUPS switches off power below an adjustable energy threshold.

  • On mode – fast start & max capacity

    In AUTO mode, the Raspberry Pi doesn’t start immediately, and the supercapacitor’s full capacity isn’t used. ON mode solves these, but safety features are lost.

Parameters – what we have designed

Energy storage device

Type

Supercapacitor

Capacitance

100-120F

Capacity extendable

Yes

Charge cycle

500 000

Operation temperature range

-40..+70˚C

Expected operating time with Rapsberry Pi 4 full load

30 sec

Physical parameters

Form factor

Raspberry Pi HAT

Stackable

Yes

Replaceable supercapacitor

No
Electric parameters

Charging current

2A

Maximum discharge current

7,5A

Maximum load current

2,5A

Output voltage

5V

Power supply

Input voltage on main connector

5V

Input voltage on auxiliary connector

5V

Raspberry Pi 5 official power supply (PD) compatible

No
Connectors

Main power input

USB-C

Auxillary power input

Yes

Reset

Yes
Communication

Method

3 GPIO port

Number of optional GPIO triplet

3

Disabling option

Yes
Setup

Mode option

AUTO-ON-OFF

Adjustable level threshold

Yes

Adjustable input voltage threshold

Yes
Safety

Reverse polarity protection on auxillary input

Yes
Control

External control of the power of Raspberry Pi

Yes
Indication

Input Power

Yes

Supercapacitor voltage level

3 LEDS

Software

Control software

C++ and Python

Documentation – Where you can find more information

Github

More information, user manual and control software (C++ & Python) can be found on Github.

Download the control software
Read the user manual
See information

Images – how it looks like

Resellers – Where can you buy it

Find AQEX Products
Find AQEX Products