I’d much rather do that than purchase a NUC with a built-in battery. Keeping the two pieces separate makes them easier to repurpose later.
Regardless, the market for such a device is relatively small.
I think it’s possible to build one. Get a bunch of 18650 cells from a reputable brand (or just an old laptop battery, if you’re brave enough), then look for a 18650 powerbank kit on AliExpress – some of these would be with slots you can just plug the cells into, without welding/soldering.
this is a supposition, but i don't think the numbers are very far off. Most powerbanks are 18650 or 26650 inside - flatter or "better" ones are lifepo or lipoly or whatever, instead of cylindrical Li-Ion. anyhow those are 4.2V nominal and USB wants 5V so all single cell or parallel'd 18650/26650 power banks are going to use a boost converter to get the voltage to 5.1V nominal at the USB terminal (assuming a dumb power bank, a power bank with power delivery will boost that even higher but also probably has multiple batteries in series, but that doesn't matter, it makes efficiency worse for our daisy chain regardless!). So these boost circuits "charge" something and store it until there's the correct number of electrons to equal whatever charge/joules is required to run the load. There is >15% wasted as heat either in the capacitor or the inductor (depending on the style of boost converter). There's another ~15% or so lost in the charging circuit, as it has to take 5.0VDC in and run a charging circuit (similar to mppt) on the battery at different voltages and/or amperages which again waste is generated as heat. Cable losses in the daisy chain probably account for a percent or two each, the indicator lights across all the power banks, plus all the microprocessors/etc inside of them probably waste another couple percent.
Look for "PD in" on this sheet for some examples (columns BW-BY): https://docs.google.com/spreadsheets/d/1SWqLJ6tGmYHzqGaa4RZs...
i left it at stock bios settings and did not put it into higher TDP mode though, since i use it as an htpc and it mostly idles, i'd rather it stay at more comfortable operating temps.
the nvme cost me more than the pc, which for $207 includes 16GB ram, 512GB nvme, and a Win11 Pro license. insane.
[1] https://www.amazon.com/MeLE-Mini-Quieter-4C-Astrophotography...
I need a somewhat powerful GPU for work, so I'm seriously considering buying one of the more powerful handhelds with removable controllers and just taking them off. The screen would be superfluous but it's probably the most powerful travel PC, at least for the price, that's available right now.
I don't even need the battery that much. But all the options I've seen for SFF PCs that would fit in a backpack look fragile and I wouldn't feel confident carrying them around often. Plus, they're either expensive (because it's a tiny market) or geared towards office work.
On the other hand, the Mac Mini exists and is exactly what I'd want in terms of hardware. Why don't us Linux/Windows folks have this option?
Also, those gaming handhelds are pretty power and temperature limited. They're often a good bit less powerful than a halfway decent gaming laptop, just a more convenient form factor for portable gaming.
There are SFF PCs a little bigger than NUCs that do have strong graphics but they're crazy expensive.
Intel's Lunar Lake is another option. The iGPU on that line will match or exceed a Legion Go too. Right now, it's mostly in laptops but some NUC models have been announced.
Have you considered dropping the portable monitor for an angled laptop stand that will elevate the screen to eye level? I've got one that collapses down small enough to fit in a reasonably deep pocket.
anyhow you can get a 12V PSU that does whatever amps (12? 15?) in a pretty small formfactor, and the "additional" stuff the motherboard needs is, as shown above, insignificant. The PSU can be pretty dirty, as in in the US do literal 10:1 winding to get 12V out (i know it'd be slightly different winding amount to account for losses in rectification and lines and whatnot but 10:1 looks nice to the math) and rectify it straight into one of those nanoPSUs. believe me i've seen me do it.
also don't ask to see my laptop DC-DC supply for running straight off a solar panel... it's larger than most NUCs, too. oh wait, you still need a laptop brick, plus the DC-DC. So you gotta DC-DC -> DC-DC -> laptop which -> DC-DC and probably DC-DC again (1.2v/3v3 rail probably clocked off 5v rail, that's what i'd do naively)
those "dashes" in "DC-DC" are doing a lot of heavy lifting
Had to do a repaste to get proper cooling.
Crazy expensive.
Less highly specced AMD-based NUC-lookalikes are like $600, comparable to low-specced mac minis.
Which is surprisingly hard to find for a portable (usb-C) battery.
Annoying during a power outage though.
Works on all APC UPSes that I've tried, at least.
It provides streaming access to from large libraries of HDR content on the go.