Increasing the amount of sunlight hitting the solar panel will not increase efficiency at all, although it might make it go farther or faster.
To increase efficiency, think reduce amount of heat and sound that is wasted. Quiet and cool means efficiency. It sounds like you can't do anything with the efficiency of the motor. Your transmission, whether it is chain, belt, or gears, needs to be light and efficient as possible. You need to make it as easy to roll as possible. Low friction bearings and tires that roll easily. You also need to minimize drag on the car from the air. The faster it goes, the more important it is to reduce the drag.
What is the best way to set up the gears for a solar car?
Well, a solar car isn't going to reach a very high speed, so, I would think you would want taller (a higher ratio) gearing in the differential. This will magnify the acceleration of whatever type of engine is putting out the limited power.
As far as placement of the solar panel, I would think that would depend on when the race starts and ends...and the duration of it. You will want it to be placed for best sun ray exposure, so wherever the sun will be located in the sky for most of the race. This will depend on the direction the car will be traveling too. Find that out and you will probably have a leg up on the competition.
Make it as light as possible so there is less strain on the motor.
Make it as wide as possible to get the most area for you to mount the solar cells. The more solar cells you have pointing directly at the light source, the more power will be available to the motor.
How can i make a fast homemade solar car with basic materials?
The easiest way to do it is to attach a propeller to the motor and not worry about gears, belts, rubber bands and bearings. Then you just have to fool with the angle of the propellor blades and reducing friction on the axles and or wheels to as low as possible, like on the wooden push cars.
Does a black solar car capture more solar energy than a white solar car?
are we talking about the car?
or the solar panels?
clearly, what color the car, other than the solar panels, is, does not matter.
the color of the solar panels is probably determined by what they are made of.
painting them, thus excluding light, is not likely to improve their performance.
black cars do tend to be hotter.
in warm climates, most people like to turn on the a/c.
that would sop up all the energy created by a solar panel.
look at what solar cars really look like.
there's only space for 1 small person.
they only run a few hours a day.
they don't go anywhere in the rain.
the problem that exists is that the amount of solar energy falling on the footprint of a car is really too small to provide the 40-80-160 hp that most folks seem to like.
they're just not going to be useful in the foreseeable future.
well if its going down hill increasing the weight might help, making the car itself more arodynamic might have negligable effects. trying reducing the size of the wheels. big wheels provide more power but end up being slower, small wheels have less power but are a lot quicker.
Can solar car chargers work without having the key to the car turned to accessory?
If your cigarette lighter works when the key if off, then yes, the solar charger will work. That will confirm you have popwer to the lighter when the key is off, thus the necessary connection to the battery.