An uninterruptable power supply is a battery that goes between your main power outlet and critical devices that you don’t suddenly want loosing power, like your PC. You can use one to power your wifi and other critical, low power drain devices, such as ham radios. They will not last a very long time, maybe a few hours, depending on what you have connected. In most instances if you loose local power the chances of your internet staying up are good, but you can only access it if your router stays powered up.
This is one such device you can find on Amazon. One of my Patron’s said this will run his wifi and a couple of other devices for about 4 hours. I currently have one half the size that just powers my wifi router and power to my ham radios, however I have other 12v batteries I can move my ham radios to as well.
A UPS is a good start to having some backup power for critical devices, mostly your communications.
I will do a show-and-tell on a portable solar kit that I won a few years back in the near future.