Solar Model Cars
Bill Kuhl
http://www.scienceguy.org
Looking for more science projects on the Internet, I ran across the Junior Solar Sprint Competition.
I have been interested in alternative energy for a long time, so I decided I would build a solar powered model car.
EverythingHobby had two Tamiya solar panels and one motor. I purchased the motor and the ½ volt 1200 mah
panel to start with thinking both panels were the same. I later purchased the other panel which was 1.5 volts
400 mah, this would be good for experimenting with trade-offs between voltage and amperage.
For my next car I purchased the panel and motor specified for the Junior Solar Sprint Competition, in my first tests
of running this car pictured above, the speed is at a jogging speed. This car was also an experiment in using
bamboo to stiffen the thin plywood chassis.
I also purchased a 10-pack of kit cars from Pitsco because the price is below $10 a car and I thought this would
be good for a class this summer. The solar cell is rather tiny so I used lower gearing to get the car to move, but it
will work fine in bright sun.
The model solar cars appear to be a good activity to learn about harnessing sunlight, electricity, electric motors,
gearing, and construction ideas.
(A)– first car I built from Tamiya components I found in local hobby shop. (B) – second car built using solar panel
and motor specified in Junior Solar Sprint rules. (C) – Sun Zoom Lite car kit was the third car I built which is an
inexpensive kit.
Applications for photovoltaic solar panels – (A) large solar panel seen at the Minnesota State Fair was available
for rent. (B) - calculator powered by small solar panel. (C) – traffic signals sometimes use solar panel to charge
battery power. (D) – small solar panel recharges battery in garden light.
Electric Motors (A)- demonstration electric motor leaves everything exposed to show how motor operates.
(B) – close-up of brushes and commutator in demonstration motor. (C) – commutator and windings seen in
Speed 400, a typical brushed electric motor.
When looking for a motor for solar power, it helps to look at the start-up current requirements as some motors
require more electricity to start than others.
(A) – Tamiya .5 volt 1200 mah solar panel (B) – Tamiya 1.5 volt 400 mah solar panel (C) - Tamiya motor designed
for solar panels. (D) – two types of lightweight model airplane wheels I considered using. (E) – the chassis of the
car was constructed of thin plywood, brass eyelets were sandwiched between balsa for bearings.
(A) – motor has been mounted on the chassis, spur gear was from radio control car. (B) – chassis has been
flipped over, music wire is used for axles, craft beads were used for spacers next to wheels. (C) – the solar panel
came with adjustable mount. (D) – thin plywood shims were put under the motor because the gears were
meshing too tightly.
(A) – panel specified for Junior Solar Sprint is rated at 3.5 volts @ 3 watts (B) – this is the motor specified for
Junior Solar Sprint (C) – I also ordered wheels, axles, and gears from Solar World (D) – craft beads I used for
spacers (E) – bamboo skewers were used to strengthen the chassis of the car.
(A) – brass eyelet worked well for bearing. (B) – underside of rear half of car shows reinforcement done with
plywood and bamboo. (C) – electric motor ran smooth with the gears provided. (D) – after seeing the pivot on
the Tamiya panel, I built my own swivel joint using a ping pong ball.
(A) – Pitsco solar car kits can be purchased in an economical 10 pack. (B) – top side of the small solar panel.
(C) – seen from the back, the solar panel is only .45 volt 400mah (D) – I measured the voltage of the panel at .47
volt in strong sun.
(A) – screw eyes make for an easy to install bearing. (B) – side view of front axle and wheels. (C) – gear font
gave the specs of all the gears included, more gears than needed but might be useful for another project.
(D) – large assortment of gears included.
(A) – using 20-tooth pinion and 40-tooth spur gear specified in instructions, the car would only move under ideal
conditions. (B) – with 10-tooth pinion the gears would not mesh with motor on top of chassis. (C) – I flipped the
car over and tried placing the motor in the rear but panel could not rest on top of the motor. (D) – moving the
motor ahead of the rear wheels should work.
** Added 9-14-2010 Klutz Activity Book The Solar Car - I built the Klutz model solar car kit that comes packaged with a book.
(A) - Klutz sells books that have kits included on a variety of subjects. (B) - Sample of the book showing full-size solar cars and
model solar car competition events. (C) - The chassis for the car is taped into the book.
(A) - all the parts needed to build the car. (B) - view of assembled car from the top. (C) - view from the bottom,
small rubberband is used for drive belt. This runs very smooth and quiet.
Added 6-13-2011
(A) Small car I designed uses solar cell from outdoor light and framework of craft sticks.
(B) The motor is pager motor from Radio Shack, larger motors would not even spin with this solar cell.
(C) I added adjustable bracket made from pipe cleaner so solar cell could be tilted.
(D) This car was pushed by propeller, motor and prop from Air Hogs Aero Ace plane.
2-16-2012 Experiments
I built another simple car from the craft sticks but the wheels were made from 3/4" flat rubber washers instead of smiley faces. The
motor and gears were salvaged from small inexpensive model helicopter that had a bad battery. Next I would like to try two of the
small cells to see if it will move the car, single pv cell from $1 yard light would not. Goal is to build a model solar car for under $5.
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Small cell from yard light would not move car. |
Pointed the cell & gave the car a push it would run. |
PITSCO cell would move & start from flat position. |
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| With another cell added in series and better fit with the gearing, this tiny car is moving on its' own. |
I modified the PITSCO solar car to use DVD layer wheels, it is faster and will travel over rougher terrain. |