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.
The usable south-facing roof area is full, unfortunately. I'll have to do ground mount in the back yard and run a bunch of conduit if I want to add any more PV.
The 32 kWh of batteries are made of two 16 kWh batteries in parallel. Since this system is in lieu of a backup generator, I have it configured to only draw the batteries down to 50%. That leaves the bottom 16 kWH available for emergency use. Basically, for day to day usage, I treat the battery as being half the capacity it really is.
I've only been running this system for about 3 weeks now, but the batteries have been operating between 65% and 90% pretty consistently even running the A/C pretty heavily. They've been closer to low 60s this past week, but the wildfire smoke was choking out the sunlight Thursday and Friday.