I’m only half kidding. I’m a bit of a prepper and I have lots of powerbanks and devices that charge from USB but besides idling my truck I really had no other way to charge any of them in case of a long-term power outage which seemed a bit of an oversight on my part.
Not like this solves the issue. 30 watts (under ideal conditions) isn’t much but it’s a start.
Ofc, that’s on a whole different level.
Your 42 kWh is huge. Pair that with an approriately sized roof solar panel, and you won’t need a grid much. Seriously, look into that. Not even for living off the grid, but for financial reasons.
Though yeah, having the lights on and appliances running, might paint a target on your house in an apocalyptic scenario. But nobody’s forcing you to use the lights, and a heat pump with ground water or earth collector as a source is pretty stealthy. So you can sit in a dark, but warm, house.