[PinguTS]

The HTW Berlin has a autarchy calculator. Unfortunately only in German language: https://solar.htw-berlin.de/rechner/unabhaengigkeitsrechner/

They also test and publish yearly the latest battery combos.

[bootsmann]

Extremely underrated how important just a small battery is for autarchy, very useful site.

[oezi]

The calculator makes it very clear that adding more batteries becomes more and more inefficient.

Being 100% independent is just completely unnecessary.