> I'd guess it'd be enough for something like 1-2 miles a day on an electric drive train

It's probably more 10~20, possibly as much as 30, if it's a long and sunny summer day FWIW.

For references:

- the F150 lightning gets close to 2 miles / kWh on average, ~1.5 at highway speeds but as much as 3~4 at consistent low speeds

- on the other side of an RV, Volvo markets their FH Electric (cabover semi) for 1.1kWh/km — 0.7 mi/kWh — at 80km/h (50mph), DAF/Innovate UK's Battery Electric Truck Trial yielded similar results (1.08kWh/km over 287000 km), it's also close to the numbers of the electric trucker in their very recent MAN eGTX video (0.83 kWh/km = 0.75 mi/kWh)