I did some nerd math to figure out what the break-even point for a fully electrified RV would be, compared to diesel.
Here's the numbers I came up with.
amortizing the expense of a solar power system to determine the per-mile expense of an off-grid solarized electric RV, and the break-even point vs a diesel vehicle.
Standard RV has around 10 mpg efficiency, at $6 per gallon (current prices, likely to increase into the future, that's 1.6 miles per dollar, or 0.625 dollars per mile, just in fuel.
Let's assume school bus dimensions. big rectangular vehicle, 40 feet long, 10x 600 watt solar panels, for 6000 watts, triple that for 18000 watts if a slide-out system is implemented.
200 kWh system around $8000 for just the batteries (if the batteries are bought on the secondhand market. I've seen a 105 kWh CATL setup online for just $3800 before), assume $10k for motor, and $10k for inverter system, $200 per panel, $6000 for panels (triple gang extensible setup with 30 panels.
$34,000 for electrification setup, not including installation.
What is the break-even point of the installation?
Let's assume over a 30 year lifespan, the electrified setup might require $10,000 in repairs, for a total of $44,000.
What is the break-even point? at 10 mpg, 1.6 miles per dollar, the electrified bus has to travel at least 70,000 miles. Is that possible?
In the summer in a sunny region, there might be 12 peak sun hours, collecting 18kWh per hour, or 216kWh per day, enough to drive between 100 and 150 miles depending on wind resistance.
In winter, assume an average of 6 peak sun hours per day, for full sun, less for cloudy days. Average to 4 in winter, for a winter average of 72 kWh per day, enough to drive 36 to 54 miles.
split down the middle, summertime range is 125 miles per day, and wintertime range is 45 miles per day.
Each year theoretical range is 22,750 in summer (just under 3800 miles per month), and 8190 in winter (right around 1350 miles per month). (split the year in half. Assume half the year is making full summer capacity, and half the year is making full winter capacity. The difference evens out over the spring and fall months.
The break-even point is just before two and a half years, which is to say, if every opportunity is take to drive as much as possible on whatever energy is in the bus, it would take just less than 2 and a half years to drive 70,000 miles.
More realistically, someone on a long perpetual road trip might drive 1000 miles a month.
At this pace, the break-even point would come at just before 6 years of driving, assuming a steady 1000 miles of driving a month every month for the whole time.
To make this somewhat more realistic, 1500 miles a month is very realistically achievable during summer, which comes out to a pace of 375 miles per week, which is plenty of time to enjoy whatever there is to enjoy.
In the winter, find a nice place to park and hunker down, or greatly limit travels. We don't need to be pretending that the world is bright and full of life in the middle of winter. Humans are made to hibernate. Chill out.