Raspberry Pi UPS - Thoughts for off shelf items

Question

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 :)

Your question has two problems it is primarily opinion based, and second shopping recommendations are explicitly off-topic per the site's FAQ — Steve Robillard, Jun 15 '18 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 — totalconfusion, Jun 15 '18 at 20:39
Possible duplicate of How do I build a UPS-like - battery backup - system? — Fabian, Jun 16 '18 at 19:42
Well, a cap has a useful life of 20-40 years, while a typical battery is dead after 5 or 10. — Dmitry Grigoryev, Jun 18 '18 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, Jun 18 '18 at 21:11

score 1 · Answer 1 · answered Jun 16 '18 at 15:45

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.

score 1 · Answer 2 · answered Jun 19 '18 at 17:55

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.

score 0 · Answer 3 · answered Jan 16 '23 at 13:07

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.

Raspberry Pi UPS - Thoughts for off shelf items

3 Answers3