This website made me reconsider if 99.9999% SLA and always online is really that important for lots of websites. I used to self-host my own server in my own apartment, but gave up on that after my internet provider had their first major outage that lasted almost a week. Also I didn’t want to worry about the fire hazard, or the server going down when I was traveling etc.
But a solar powered server seems interesting, if the batteries could be made fire safe.
Uptime for home users is useless. More important is recovery, reboot and resume (the 3’Rs)
You server should reboot automatically, storage should restore itself from unsafe shutdown and your services should resume operations like nothing happened.
This means test your reboot, ensure stuff doesn’t break, and so on.
Failing storage after an hard reboot is the hardest.
For network, i have two ISP connections and a an auto switch script Incase one goes down. But honestly it’s overkill and not needed for 99% of home hosters.
Buying some kind of UPS like a battery powered power strip is also nice but keep in mind that require maintenance to replace batteries once every few years (long enough to forget) and so be useless. The ups shall only last enough to perform a controlled server shutdown using NUTS.