This is excellent, wait does this actually work

Depending on how the laptop is setup, it probably does (many are actually pretty "accepting" of slightly varying voltages because they're just charging a battery/changing the voltages internally anyway).

You can also get an "official" adapter for the various battery brands such as this: https://www.milwaukeetool.com/Products/Batteries-and-Charger... (45w over USB C) or https://www.dewalt.com/product/dcb094k/usb-charging-kit (100w over USB C)

Yup. https://i.imgur.com/hYRje5h.jpg

Plug adapter is https://www.ebay.com/itm/253555244977

And I just hacked up an old cheap hat charger to become an output connector.

I miss the days when the ThinkPads came with both an internal swappable battery and external swappable battery. You could just swap out the battery if it was running empty and continue working. All of this is neat and all, but it's a horrible messy kludge in comparison.

Oh no, the laptop has that too. :) It's a T460, has a 23.5wh internal battery under the palmrest, part number 45n1113, and another also-23.5wh removable battery that slides out the back, part number 45n1127.

But Ryobi batteries are cheaper than Lenovo batteries, and I can use them for more other stuff so it's easier to justify owning a whole pile of them.

I miss the days of the docking-station-shaped "battery slice" which added even more to the bottom of the machine. But evidently they may still make those and I'm just not seeing them in the wild? Anyway, the Ryobi solution is so simple and efficient, it's not worth shopping for alternatives.

Ah right; it just seems like a right hassle to carry around.

Ryobi does sell inverters for their 18v batteries though: https://www.ryobitools.com/products/details/46396026750