How long will it keep running?
The short version
Tap what you want to keep on during an outage. You'll see how long each size of battery lasts, and how big a surge it has to handle.
Together they average about 20 W (0.5 kWh a day). The biggest startup surge is about 150 W, so pick a station rated for at least that.
Add a couple of folding panels and a power station refills itself on sunny days, so it can run indefinitely for small loads. See the emergency guide.