That may be true, but I don’t think it matters that much in this context, because the actual implementation isn’t the point. It’s more about the idea behind it.
Can’t wait to see it!
I think I have the gear to set up the solar panels into a controller that offers a USB output without the 2000Wh battery, and could set it up into a far more reasonable USB power bank, though I'm not sure I have one that can be charged at the same time as it discharges. It's still a day minimum for an RPi to discharge one of those with a touch of tuning, and far less than a day to recharge them.