Just like to share a bit of recent experience looking for a working solution to small powercuts we have here, usually either milliseconds up to 2 hours sometimes.
People tried to resolve this with power banks that usually do not work as the supply will be shortly cut when powering them on again. Also they are comparatively expensive.
Which brings me to the latest experiment that actually works and it cost only ~3$ plus the 2 LiIon batteries which can be recycled from an old powerbank or a laptop.
This small UPS can supply 5V at up to 3A advertised. More realistically and actually measured load is 1.5Amps with an Orange Pi 5. So the higher powered SBCs should all work, and no issue with the smaller ones. It actually lasted for 4 hours (!) with 2 old 18650 cells 1200 mAh measured each.
And here it is. You can order from Ali or any other online store. Just look for the pic. Also have versions for 9 and 12V. Search for something like “DC-DC Step Up 5V 3A 15W Type-C 18650”. It is a step up based on XR2981 and charge controller TP4096.
There are several of these types of UPS’s/LiIon → 5vdc boards
The biggest thing is to ensure it is capable of putting out at a minimum 2-3A at a stable output with minimal ripple…some of the newer processors on these SBC’s can easily draw too much power and cause a brownout or reboot all together.
You get a stable output up to 3A with the 3$ one. I measured 1.5A when charging and powering the OPi5, so that should be the same as an RPi4 with Rockchip.
There is one thing, when it is really down it wont reboot instantly after charging again. Batteries need to be back at ~3.8V first before it boots properly. Otherwise it crashes in between, there is some power spike. Tried several things with capacitors and supercapacitors at different connection points to no avail. Meaning there will be some reboot loops until it reaches that voltage. Seems to be an issue with the 4096. But that is after 4 hours, so it’s almost unlikely to happen anyways.
I’m going to add an ADC (ADS1115), waiting for it to arrive, then perhaps get some better measurments.
OOH!! I just got my Protectli Uninterruptible Power Supply for a whopping $39 [$43 shipped to my door!]
This thing is an actual UPS…it takes 12vdc in (from a AC-DC converter), and outputs 12vdc at up to 5A…
I’ve been experimenting with this module recently. While running, The XR2981 chip gets hot. Can’t touch by finger. Is this normal? Or should I put some heat sink?
Edit: My devices drawing 2.8A when Batteries are at around full charge.
I would definitely put a heatsink…I think they are rated for 2A so be careful with the current draw.
What device is pulling 2.8A?
I can say with confidence that these modules (make sure you select dual batteries and 5vdc) do work well as a UPS…I got 2 of them, 3D printed the case, soldered in a USB A port and put 2 used harvested 18650 cells from a cordless drill and it runs my OPiZero2W with no issues
I think they are rated at 5V/3A, so you are runnig at max. I have an OrangePi 5 on it and it does not even get hand warm. No cooling needed, not on the UPS module and not on the Pi (I have the cooling kit but disabled the fan, so it’s pure passive).
One reason yours is getting so hot could be a too high input voltage, I just use a standard USB 5V charger. If you power it with 9V or 12V it will get hot.
