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.

Important addition: You’ll have to set browser.urlbar.update2.engineAliasRefresh to true in about:config to see the option to add search engines via URL. Otherwise you’ll just see the option to remove them and a link to the add-ons page.