Semi-agree w your mostly agree w @Cheesesteak. Any piece of emergency equipment, even a traditional full-sized spare tire, needs to be serviced periodically. The kind of folks who buy stuff and throw it in the trunk unseen, expecting it to be useful 5 years later are fooling themselves from the git-go.
When I bought a rechargeable jump starter I charged it fully and set a task to check it 4 months later. When my computer alerted me I brought it inside and found it was still full. Waited a couple months, checked it again, and found that after 6 total months (in a benign climate) it was down to 3/4ths. So I recharged it, set a repeating task to check & charge it at 8 month intervals and now it’s out of sight out of mind. My computer will bug me when I next need to think of it. But now I’m confident it’ll be useful to me whenever I eventually need it.
IMO that kind of thinking is the minimum buy-in for everything seldom use. A plug-in compressor may seize, the stuff in a first aid kit will dry out or rot or …, your cold weather emergency blanket will become mold- and mouse-infested etc.
My bottom line to everyone:
“Buy it, dump it in the trunk, and forget it” is a plan to fail. No matter whether the thing has a battery or not.