alt Hacker NewsThat actually sounds like a pretty good plan.
I did something similar with my lawn mower. I bought a battery and a single solar panel from Harbor Freight, along with the controller and wires need to hook it all together. I'd set the panel in the yard when I needed to charge the mower's batteries.
The whole thing, including the mower, cost less than half a year's fees from a yard crew, and I ended up saving money overall.
After the experiment was done (and I realized the mower was too low for my grass and was harming it) I sold the mower and gave the rest to my father-in-law for his shed.
We then got professionally installed solar panels for our house and a full-house battery. (It isn't strong enough for the air conditioner, but oh well.)
If I had it to do over again on the small scale, I'd buy an Ecoflow battery (which I have actually bought) and a solar panel made for it, and your fridge idea is a good one. It'd probably also power a fan, a light, and some light entertainment, I think.
Edit: Might go with "Anker" or "Jackery" instead of Ecoflow now, as it might be cheaper for the same thing.
For comparing those brands (EcoFlow, Anker, Jackery), you might want to check the wh/$ ratio - it's basically the best way to compare power station value (for newer LFP systems). I went through this same analysis recently - gearscouts.com [1] has a pretty good comparison table that tracks actual street prices vs capacity.
I've found the sweet spot is usually in the 500-1000Wh range for emergency backup. Enough to run a fridge for 8-12 hours but not so big that the solar panel costs get crazy. The LFP (LiFePO4) models tend to last way longer than the regular lithium ones - worth the extra cost if you're planning to use it regularly.
Your lawn mower experiment sounds like it was a good learning experience! Those small Harbor Freight panels are great for tinkering. I started with something similar before going to a full house system.
[1] https://gearscouts.com/power-stations