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I've been looking at off the shelf raspberry pi UPS/shutdown controllers. I've come up with 4 and wanted somebody to weigh in on the choices.

My use case is pretty strait forward. I want the pi to shut down gracefully when mains power is lost. I'm not fussed about any other functionality. I'm running a Pi2 - might move to a Pi3 at some point. Smaller form factor of UPS unit is nice but safe operation comes first.

Anything else I should be considering? Is the capacitor on the pisaver any safer than the lifepo4 battery for example?

Thank you raspi community :)

lifepo4weredpi3

pisaver

upspico

mopower

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    Your question has two problems it is primarily opinion based, and second shopping recommendations are explicitly off-topic per the site's FAQ Commented Jun 15, 2018 at 20:13
  • I'm trying to find the right component for an electrical project. One that doesn't explode and does it's job keeping my data uncorrupted. If you need a question it's here - What are the consequences of using a cap as opposed to a battery Commented Jun 15, 2018 at 20:39
  • Possible duplicate of How do I build a UPS-like - battery backup - system?
    – Fabian
    Commented Jun 16, 2018 at 19:42
  • Well, a cap has a useful life of 20-40 years, while a typical battery is dead after 5 or 10. Commented Jun 18, 2018 at 10:54
  • I have zero experience with this so-called "Geekworm" unit, but it's a lot less expensive than the others you've listed.
    – Seamus
    Commented Jun 18, 2018 at 21:11

3 Answers 3

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Providing continuous power to the Raspberry Pi can be accomplished in several ways:

  • line voltage UPS (large, heavy but generally useful for many line voltage devices)
  • 5V USB UPS (small, light, limited to USB devices)
  • 12V rechargeable battery with USB ports and simultaneous charge/discharge capability (medium weight and portable, provides 5V USB, 12V)

Think of UPS as a rechargeable battery that can be charged/discharged at the same time. This may give you more options when shopping. I have bought and used all of the above for different use cases with my RPi's. Considerations include:

  • size (e.g., pocket, desktop, deskside)
  • portability (travel, field)
  • voltages (5v, 12V, line)
  • capacity (amp hours)
  • indoor/outdoor (outdoor UPS should be lower voltages for safety)

The choice of brand is up to you. We do not endorse.

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I've settled with a PiJuice HAT. https://uk.pi-supply.com/products/pijuice-standard

It's not a cheap option nor is it the right option for everyone looking for a UPS. However, it does look well designed and offers the functionality I require (Conditional soft shutdown on mains loss)

The question still stands about the safety of a a cap vs. a battery based system.

Which one might fail (explode) and, why?

Would a super-cap even offer enough juice to soft shutdown? (like offered with the Pi-Saver)

What would sit better in an industrial control unit left untended for years on end?

SD corruption is something I've dealt with and am trying to avoid with this system.

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I offer an answer that I just found (and tested) on Aliexpress; it is not made to the Pi or anything, it is just a regular voltage regulated 5A UPS: https://pt.aliexpress.com/item/32783727347.html .

You can regulate the output voltage between 4 and 23V, so I would really recommend making it output say 12V or 15V and then passing it on a buck (say LM2576) to 5V.

I have been using it in my current project (a 9V/5A isolated miliohmmeter) with the Pi 4 and a 7" HDMI display, using 6 li-po (2 paralell 3 series) and obtaining 5+ hours of battery life.

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