I bought a Portable Power Station (e.g. Anker SOLIX C300) to use as an Uninterruptible Power Supply (UPS) for my homeserver (~ 40 Watt) to buy me - or better my utility company - a few hours in case the power fails.

If you want to use Kiwix as posted by @ChogChog@lemmy.world above, you can find the data here: https://dumps.wikimedia.org/other/kiwix/zim/wikipedia/

The latest (January 2024) total dump for Wikipedia (English) is: wikipedia_en_all_maxi_2024-01.zim

…but there’s other languages and sizes available as well.