To make a small solar-powered model car, build a light, straight chassis, mount two freely turning axles and wheels, attach a small solar panel and low-voltage motor, and connect the motor to an axle with a gear, belt, or friction drive. Test it in direct sunlight, then adjust the alignment, friction, panel angle, or gearing. This guide covers an educational model car; a road-going solar vehicle involves separate vehicle, electrical, structural, and safety engineering.
Parts and materials
You can assemble the car from separate components or use a solar-car kit. A kit can reduce the work of finding compatible parts; building from scratch gives you more freedom to choose the chassis and layout.
As an Amazon Associate I earn from qualifying purchases.
- A small solar panel compatible with a low-voltage electric motor
- A motor, two axles, and four wheels
- A light, stiff chassis, such as corrugated cardboard
- Axle supports or bearings; drinking straws can serve as simple axle bearings
- A gear pair, belt, or friction drive to transfer the motor’s rotation to an axle
- Secure electrical connections, such as alligator clips
- Mounting materials; paper clips are one simple way to support a panel
For reference, the National Renewable Energy Laboratory supplier list specifies 3 volts at 3 watts for certain listed Junior Solar Sprint and Ray Catcher panels. That is a specification for those products, not a universal requirement for every model car. NREL’s component supplier list names kits and parts from suppliers including Solar Made and Pitsco. Pitsco’s SunZoon Lite listing describes a kit with a chassis, panel, motor, gears, wheels, and axles and marks it as a clearance item; check the listing for current availability and terms.
Build the car
- Make the chassis. Cut a light, reasonably stiff base. It must support the panel, motor, and axle supports without flexing enough to throw the parts out of alignment.
- Fit the axle supports. Attach supports under the chassis, keeping the front and rear axles parallel. If using straws as bearings, make sure each axle can turn freely inside its support.
- Install the axles and wheels. Check that the wheels are secure and do not rub against the chassis. Spin each axle by hand to find friction or binding before adding the motor.
- Mount the motor and transmission. Fix the motor firmly to the chassis and align its gear with a gear on one axle. A belt or friction drive can also transfer rotation. The drive should engage without being so tight that it binds.
- Attach the solar panel. Secure it above the chassis and handle it carefully; the panel can be fragile. Choose a position where it is exposed to light and does not interfere with the wheels or drive.
- Connect the motor to the panel. Use secure connections between the panel leads and motor terminals. Keep the wiring clear of moving parts.
Test and tune it in sunlight
- Hold the car in direct sunlight with the panel facing the sun. Check whether the motor turns and whether the drive rotates the axle.
- Set the car on a flat, open surface and let it run. Note whether it starts, travels straight, or stalls.
- Change one factor at a time: reduce rubbing, correct axle alignment, improve a slipping drive, adjust the panel angle, or try a different gear combination.
- Record each change and what happened. Speed and distance depend on the particular parts, light, and surface, so there is no single result to expect from every build.
Gearing involves a trade-off: a combination that spins the wheels quickly may not start the car as readily, while another may provide more turning force at the wheels. Test rather than assuming one arrangement will work best. NREL’s Junior Solar Sprint guide describes the design choices as having “never one right answer.”
#1 Best Overall
- SOLAR-POWERED SCIENCE FUN: Build 4 solar-powered toy cars that convert sunlight into motion! Each kit contains everything required, a mini screwdriver, and step-by-step instructions for hands-on STEM learning. Watch physics in action as solar energy drives the wheels—no batteries required! (Pack contains 4 cars, 4 manuals, 4 screwdriver)
- PERFECT FOR YOUNG ENGINEERS: Designed for kids ages 8-12 to explore robotics, engineering, and renewable energy. Ideal for school projects, STEM clubs, or family bonding. Younger builders (under 8) can participate with adult guidance, fostering teamwork and problem-solving skills
- BOOST CREATIVITY & CRITICAL THINKING: Combines science, technology, and crafts to spark curiosity. Enhances fine motor skills, logical reasoning, and environmental awareness through interactive play
- THOUGHTFUL GIFT FOR CURIOUS MINDS: Packaged in a colorful box, this STEM kit makes a unique birthday, holiday, or back-to-school gift. Parents and teachers love its educational value, while kids adore building and racing their creations
- DURABLE & SAFE MATERIALS: Made with non-toxic and premium materials. Weather-resistant components guarantee long-lasting durability for indoor and outdoor adventures
Troubleshoot common problems
The motor does not turn
- Move the car into direct sunlight and point the panel toward the sun.
- Check that the clips or other connections are secure and that the wiring is not broken or loose.
- Turn the axle by hand to see whether a wheel, bearing, or transmission is jammed.
The motor turns, but the wheels do not
- Check that the motor gear meets the axle gear; gears that miss each other will spin without driving the axle.
- If the gears are pressed too tightly together, loosen the alignment so they can turn without binding.
- For a belt or friction drive, check whether it slips or fails to contact the axle.
The car moves slowly, stalls, or veers
- Check that both axles are parallel and turn freely, and that wheels are not rubbing on the chassis.
- Make sure the chassis is light enough for the motor to move but stiff enough to keep the drive aligned.
- Check that the panel is aimed toward the light and try a different gear combination if the car struggles to start or moves too slowly.
What this project can—and cannot—tell you
A model car is a way to explore how light, friction, mass, alignment, and transmission affect motion. NASA lists a solar-powered car activity for grades 5–12 with a 30-minute activity duration; that is the duration given for NASA’s activity, not a guaranteed build time for every student or design. NASA’s Solar Power activity is one classroom starting point.
Do not treat a classroom model as a recipe for a road vehicle. The U.S. Department of Energy describes vehicle-integrated solar panels as a possible source of range extension or auxiliary power, alongside distinct integration and safety challenges. Its vehicle-integrated photovoltaics overview addresses that separate engineering problem.
Rank #2
- Junior Solar Sprint is a fun, hands-on educational program for middle/high school students to design and construct a solar powered model car.
- Includes the required solar panel and motor. The rest is up to the imagination of the student.
- Durable, reusable solar panel measures 4.5" x 13" (inches) and has an output of 3V @ 3 Watts.
- Kit meets the regulations for Junior Solar Sprint competition.
Model-car builds can also support organized design challenges. In a 2019 NREL report on its 29th Middle School Car Competition, 232 students from 19 middle schools created 82 model cars, which were judged for design and raced in time trials on a 20-meter track. Those figures describe that event, not all solar-car programs. NREL’s competition report gives the event details.
Quick Recap
Best Value
- 4 SETS WOODEN STEM KIT: These science kits contain a solar powered car, a solar powered plane, a wind powered car and an electric fan. Each toy is individually packaged. Kids will be proud of building their own models
- FAMILY BONDING TIME: Doing scientific experiments together is a good way for parents and children to build a great family relationship. Complete science projects with your kids as their friend and teacher, that’ll be an unforgettable and precious time
- UNIQUE GIFT IDEA: Our kits designed for kids age 8-12 are cool stuff for a budding inventor, very suitable for elementary students to show their talents in a science fair. Packaged in a beautiful gift box, these assembled electronic gadgets are perfect gifts for boys and girls for birthdays and Christmas
- LEARN BY PLAYING: Fun Projects! Encourage your kids to build their own model kit and enjoy DIY STEM activities. By playing with these electric toy kits, children's curiosity and interest in physics will be stimulated, and they'll know how much fun it is to create a simple model by themselves
- EASY TO ASSEMBLE: Circuit connection is very simple, NO welding, suitable for kids to complete independently. Includes detailed instructions make it much easier and convenient to assemble the models
Rank #4
- Junior Solar Sprint is a fun, hands-on educational program for middle/high school students to design and construct a solar powered model car.
- Includes the required solar panel and drive-train (motor, axles, wheels, etc.). The rest is up to the imagination of the student!
- Durable, reusable solar panel measures 4.5" x 13" (inches) and has an output of 3V @ 3 Watts.
- Kit meets the regulations for Junior Solar Sprint competition.
Rank #3
- COMPLETE KIT: 6-in-1 solar-powered STEM building set includes wooden parts to construct a satellite, helicopter, and 4 different vehicle models
- EDUCATIONAL VALUE: Hands-on learning experience combines engineering, renewable energy, and physics concepts through interactive building projects
- SOLAR POWERED: Each model features working solar panels that harness sunlight to power moving components, demonstrating renewable energy in action
- AGE APPROPRIATE: Designed for children ages 6-14, with detailed instructions and pre-cut wooden pieces for easy assembly
- DIMENSIONS: Models range from 6-8 inches in length, with the satellite measuring 8.07 x 4.92 inches and vehicles approximately 7.09 x 4.33 inches
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
