A solar conversion is a fun and educational way to bring new zing to an old toy car. Although hobby-size solar panels produce low currents more suited to charging batteries than turning motors, they can still supply enough juice to run a small car with low power requirements.
Calculate the operating voltage and current drawn by your toy car. As a rule of thumb, two fresh alkaline AA batteries in series, end to end, provide a total of 3V and a current of 700 mA. The same two batteries in parallel, side by side, will provide 1.5V and a current of 1400 mA. A single alkaline AA battery should have a voltage of 1.5V and current of 700 mA.
Select a solar panel with a voltage and current rating close to your car's needs. However, if the solar panel does not produce as much current as your original batteries, the car may still run, but at a lower speed. Solar panels may be connected in parallel to increase current.
Locate the battery panel of the car. Open it and test your solar panel in strong light by attaching the positive, or red, lead of the panel to the positive connector of the battery holder, and the negative, or black, lead to the negative connector. If the car will not power on, your panel may not produce enough current.
Mount the solar panel on the roof of the toy car, using tape or hot glue. If necessary, add cardboard or wooden supports to tilt the panel.
Run the leads down to the battery holder, and solder or tape them to the contacts. If the leads are not long enough, splice them with extra wire and insulate the joints with electrical tape. Hot glue any loose wire to the car or panel.
If the car does not run, try adjusting the angle of the panel or going outside in bright sunshine to increase the amount of light.
Things You Will Need
- Lightweight, battery-operated toy car
- Two AA batteries
- Hot glue gun
- Mini solar panels
- Insulated wire
- Wire-cutting/stripping tool
- Soldering iron
- Electrical tape
- Panel supports
Instead of soldering the solar panel leads directly to the terminals, attach them to alligator clips so you can turn the car off and on by detaching and reattaching the clips. If the car runs backwards, try reversing the leads.
Hot glue and solder are burn hazards.