[Prepadoodle]

The problem is that 1 horsepower equals about 750 watts. (745.699872 w if you wanna be picky) So 2100 watts is only about 2.8 HP.

Since they wouldn't be oriented right, you would expect maybe half this. You also lose power in the wiring and when you convert or regulate the voltage. In the end, you would end up with just over 1 HP on a sunny day, and the panels/cells are kinda heavy. You would have to cart this weight around at night and in rain, and at other times when the sun isn't out. You wouldn't see a net gain from putting panels on a car.

Yeah, thin film and other super light cells exist and would change this a little, but probably not enough to make it worth doing. A better solution might be to roof parking lots with solar panels and let each parking slot plug in to recharge. The excess power could go to the grid.

An idea I have been playing with is to design electric cars that use snap-in modular batteries. These would weigh like 20-25 pounds and each give you about 10 miles. Your trunk would hold maybe 10-20 of these in a rack. Existing gas stations could have solar or wind powered chargers (or charge off-peak to even the loads) and would allow you to swap your discharged batteries with fully charged ones for a fee, much like you would exchange a propane tank. This would give electric vehicles unlimited range, and keep the gas stations in business as we transition from fossil fuels. This would be better than going with a fuel like hydrogen because it wouldn't require us to build a whole new distribution infrastructure.

 

[Prepadoodle]

Watts are a unit of power. P=IE, where P is power in watts, I is current in amps, and E is potential in volts.

A 2100 watts of solar at 15 volts will produce 140 amps because 15 X 140 = 2100. If you fed this into a 96 V system, you would see 21.875 amps, but still have 2100 watts because 21.875 X 96 = 2100. In other words, the power has to remain constant, so if you increase the voltage, you have to decrease the amperage. Power is the ability to do work, and that ability isn't affected by the voltage.

Look at any motor rating. A 1 HP motor will draw twice as much amperage at 120V than it will at 240V, but it's still a 1 HP motor. (a horsepower is another unit of power, and is equal to about 750 watts)

Edited to add:

A 240 watt panel at 24 V will put out 10 amps. 2 of them will put out 480 W, which would be 20 amps at 24 VDC if wired in parallel, or 10 amps at 48 VDC if wired in series. (24 X 20 = 480; 48 X 10 = 480)