It's about time they figured out how to do a solar powered car. Way overdue.

Miracle must be inserted: The Sun is brighter. How much brighter? Let's quickly estimate.

A car needs about 10kWe just to keep moving. The maximum Sun insolation is about 1kW per meter square. The surface area of a car that we can stick solar panel on is about 3 meter square. That means the unrealistic maximum power a car can receive from the Sun is only about 3kW.

Now, get real. The maximum efficiency of a solar panel achieved in the best labs in the world is only about 25%. This would give a car the maximum power of only 0.75kWe.

So the Sun must be about 13 times brighter.

Let's dream that Toyota engineers invented a solar energy receiver that has 100% efficiency. Then the Sun only has to be 3.3 time brighter.

"Although the sun will shine the same,
I'll always look to a brighter day." - Mariah Carey

Ok, let's do get real. You are talking about real time energy production to the power system. The way most people use their vehicles is to park them outside while they work or shop or whatever.

The goal here should be *REDUCED* dependence on fuel, not elimination of it. As you say Lum, total coverage will not be possible. But better battery tech will help capture the Sun's rays during periods of inactivity (when the car is parked in the sun). That WILL increase overall gas mileage and depending on where you live, the savings could be significant.

Ahmen, CT

Luminous, it's that type of negative thinking that kept us off the Moon and had people thinking the world was once a flat surface. At least they (Toyota) are trying. I agree with CT, that it will assist us in using the Sun to help move away from oil dependancy. If it provides 80-100mpg vs the already good 50mpg, I'm all for it. Keep up the good work Yoda!

Luminous is correct. One simply can not make a viable solar powered vehicle or even one that has a significant power contribution. The energy/unit area is just not there. You really can't break the laws of physics.

Now, one can cover their roof with tens of thousands of dollars of solar cells, leave the car at home all day for charging then take a short trip to the mall after work to demonstrate to all the neighbors how superiorly "green" one is.

And isn't that all you really need? Toyota understands that green is a religion and doesn't need to be rational. Good for them.

I don't think powered should be their idea. I think it would be a good method to help charge when parked, but not the sole source of charging.

USREFL,

The current world record for conversion from solar to electricity was set on 02/02/2008 is 31.25%. I was a part of that solution.

It's a long shot, however, it is still doable. Let's just crossed our fingers and hope for the best.
Go solar power!

First: Replace all exterior body panels with solar cells, then replace ALL light exposed surfaces Inside the vehicle as well such as dashboards side rails, which would give an additional 30% surface area. If you included solar fabrics as well this would be as much as 50% more light gathering surface area.
All light exposed surfaces of the car must be cosidered such as windows (dye sensitized solar glasses) wheel wells ( convex hubcaps) so about 1.5 suns brighter is all that would be needed for full power runs, but with idle time this wouldn't be needed at all, recharge times on an electrospun carbon non-fiber capacitor battery system has the highest energy density in the world. This power storage option charges very very quickly and can be discharged as fast as needed. it is also very light weight and doesn't explode when you use them.

First: Replace all exterior body panels with solar cells, then replace ALL light exposed surfaces Inside the vehicle as well such as dashboards side rails, which would give an additional 30% surface area. If you included solar fabrics as well this would be as much as 50% more light gathering surface area.
All light exposed surfaces of the car must be cosidered such as windows (dye sensitized solar glasses) wheel wells ( convex hubcaps) so about 1.5 suns brighter is all that would be needed for full power runs, but with idle time this wouldn't be needed at all, recharge times on an electrospun carbon nano-fiber capacitor battery system has the highest energy density in the world. This power storage option charges very very quickly and can be discharged as fast as needed. it is also very light weight and doesn't explode when you use them.

toyota can try solar and dynamo (htbrid) to charge the battery.....

jump on it!