A mini UPS with 5V, 9V, 12V DC output and optional PoE can be used to power a WiFi access point, a broadband router, an SBC, ...
The Luminous Zelio+ 1100 Inverter is a 900 VA/12V pure sine ... for uninterrupted power supply. Buyers find it compact, silent, and reliable, but some mention battery backup duration varies ...