Is a powerbank an efficient and safe UPS for a RPi? I was at some point told powerbanks are not a good solution for Pi's, but I cannot remember the reasoning.
I have been using Mi powerbank 2i for my Rpis for last 9 months or so. I have had zero issues with it. The advantage of using 2i are,
1. It's dirt cheap than any other solution I found($15, I use 10k mah version)
2. I can plug RPi to it and I can plugin a charger in 2i. When the main power cuts off, It'll instantly switch over to battery with 0 downtime. I think this is called passthrough charging)
3. It can provide 2.5 or 3.5 amps(not sure about exact value) output
> 2. I can plug RPi to it and I can plugin a charger in 2i. When the main power cuts off, It'll instantly switch over to battery with 0 downtime. I think this is called passthrough charging)
This alone is a killer feature that’s far less common than I expected before I started searching for it. Most power banks cut off output while they’re charging, and many require physically re-plugging the device to start powering it again.
I ended up acquiring a PiJuice for this functionality alone.
I have never measured it. At worst the main power has gone down for a 2-3 hours and it lasted at least as much. I don't have a USB power meter to measure the power taken by the Rpi so I can not give you an exact number but I would guess it to be at least around 5-10 hours if not more.
Edit: Someone linked pijuice project. I went to their website and according to them, Their 10k mah version lasts 24+ hours
> Onboard 1820 mAh off the shelf Lipo / LiIon battery for ~4 to 6 hours in constant use! (with support for larger Lipo Battery of 5000 or 10,000 mAH+ to last up to 24 hrs +)
That depends on the powerbank. Many powerbanks with Quick Charge 3.0 support will supply over 4A at 5V without power delivery negotiation. It's a hack, but so is the Raspberry Pi - I wouldn't trust a powerbank for anything critical, but I wouldn't trust a Raspberry Pi either.
Can you clarify why? Surely they are just normal batteries with a charging circuit? I'd have thought it was more a problem with "pass through charging" where the battery needs to discharge (RPi) and charge at the same time.
