Something like this.
That one seems like it has a pretty small battery compared to the ones ingame though.
Neither, spend some more and get a UPS.
https://www.amazon.com/dp/B085JJZDFK
https://www.amazon.com/dp/B00DBAA696
Its extra piece of mind for sudden power outages or brownouts. Not meant to run your devices for a long time just long enough for you to shut them down properly in the event of an outage or get you through those quick flash outages that only last a second or two in bad weather.