Who said old button cell batteries are useless?

Stack a lot of them in series and squeeze every last milli-ampere from them...or create a high voltage DC source.

Just stack all your (20mm) button cells +/-/+/-/etc. in series.

I filled mine half-full and measured 63V !!!

Prusa

Prusa Mk2

No

No

0.4mm Nozzle, 0.2mm Layer Height

20% HoneyComb, and 5 layers wall, top and bottom.

Use a 5mm Brim and 5mm Skirt.