Sheesh, you're being argumentative, I agree with you.
That's why I said "energy density of sunlight just isn't there." There's no way around that we get no more than 1.4 kW/m^2 of radiation. But before 1940 the idea of a PV cell at all was only hypothesized so we're in our infancy in the field.
That may be. But the reality is that you won't get more energy than that (at the very, very max - ideal position of the sun etc.). So it doesn't matter if PV cells are around 25% efficient, or even if they were only 3 % efficient by now. We know for a fact how much we should be able to get at the very max. And even the max is not enough.
The paradigm I'm speaking of is a 4WD box van that is heavy and not particularly aerodynamic. It might be feasible already to spend one day charging and the next going 250 miles on a motorcycle or e-bike. That's already the case. How far will 10 gallons of gasoline take each of those right now?
That's not a "paradigm". But, yes, you can charge for 250 miles for one day, but you can't actually carry that much solar on an ebike or motorcycle. And for an ebike to go 250 miles in a day? Yeah, not happening. At that stage it would have to have a huge battery, it would have to be even bigger if you aimed to do that many miles in ten hours or less (drag), and at that stage, you basically have to have a huge battery like in a motorcycle. And with that comes an increased need for solar panel wattage, and therefore panel size/panel numbers.
So the paradigm shift would be for off grid travel huge MANs and Unimogs can't be used anymore.
Yikes, you want to go 250 miles
offroad? Yeah, you have to at least double (triple, or even quadruple) the Ah of the batteries, and likewise for the solar panels.
I never said I welcome what seems like a negative evolution in our technology. That's a philosophical argument, though. Is it really any better to perhaps put a solar farm every 100 miles to charge vehicles in the Australian Outback than burning fossil fuels?
Who would pay for that sort of grid and to maintain it? If you have solar farms that has to story battery somehow, why not build out the normal grid with charging stations and power that with much bigger solar farms and wind?
Is it at all practical to attempt solar charging if it takes four times as long?
It takes way longer than "four times as long" if you have to carry your own panels.
Now you need to carry 4 times the water and food, which puts you in a downward spiral of adding weight that reduces range to the point it can't be done at all.
It does take way longer than 4 times, but you could charge a pretty large battery bank with (a lot of) solar in a couple of days or three, whereas it may only take 1-2 hours to charge it with a level 2 charger. But if you really want to go off grid, you will be out for a couple of days or even a week anyway. I am not sure carrying "extra" water is that much more in practice. You want to carry enough water anyway or a way to clean water (and knowing how to find it).