The numbers won't be as much as you could hope for:
For example Southern California might get an average of 5 to 6 kWh per Square Meter each day, but that is only the amount of energy falling on the Square Meter of area. (A Square Meter is 3.28 feet by 3.28 feet, roughly 10.8 square feet.) Our best solar panels can convert up to 25% of this energy; however most are around 15% efficiency.
Take the area of a sheet of plywood 8' x 4' or 32 square feet. Now take 32 square feet / 10.8 square feet to a Square Meter = That gives us about 2.96 square meters of area, BUT at 25% efficiency it's 1/4 of that or 0.74 Square Meters. 5 to 6 kWh x 0.74 = 3.7 to 4.4 kWh per day.
Now the Smart Electric battery capacity is 17.6 kWh, so a whole day of charging would charge the battery from 1/5 to 1/4 capacity. With a range of 76 miles, that's about 15 to 19 miles after a whole day of charging.
Detailed data is found here:
Solar Radiation Data Manual for Flat-Plate and Concentrating Collectors