How to Build LEGO Solar Cars

Solar power is an increasingly popular idea, and one which is just a really cool and savvy concept. Heat and light energy from the sun is constantly flying toward our planet, so we've built devices--solar panels--which turn that energy into electricity. A great way to experiment with sun energy is making a LEGO solar powered car 2. If you have a solar panel, the trick is wiring it to a LEGO motor to make a car run 1. This isn't difficult, but requires a little extra work.

Build a LEGO Car

Build the chassis for a car out of LEGO bricks. You can make it any size or shape that you choose, but make sure to include somewhere to mount the motor and solar panel, as well as building points for the axles to attach 1.

Connect a tire to a Technic rod. Use a rod which is long enough to fit through the car with extra length to attach wheels on either end. Repeat to make two wheel axles.

Thread one axle halfway through the chassis, then attach a Technic gear to the rod inside the vehicle. This gear will become the drive gear for the car.

Push both axles all the way through the car, then attach the remaining wheels. Test the vehicle to ensure that the wheels roll freely, but aren't too loose.

Attach a gear to the LEGO motor, then attach the motor to the chassis so that the motor's gear meshes with the drive gear.

Connect a LEGO wire to the motor, and leave the other end loose, but hanging out of the vehicle.

Mount the solar panel on your car. You need to point the solar cells upward to collect solar rays. Make sure you can access the wires or LEGO connection point on the solar cell so you can wire the solar cell to the motor.

Connect the LEGO wire to the solar cell. If you are using a LEGO brand solar cell, attach the hanging wire from the motor to the solar cell at the metal connection point. If you are using a solar cell that doesn't connect to the LEGO motor with the LEGO wire, see the instructions below.

Wiring a Solar Panel to a LEGO Motor

Select a LEGO wire that you will not use again. Make sure this wire is not connected to a power source or any components.

Cut one of the brick connectors off the end of the wire,and split about 1 inch of the wire.

Strip about 1/2 inch of the wire, exposing the copper wire. Place the wired brick on the table so that the wires point toward you.

Attach the left cable to the red or positive lead on your solar cell. Twist the two wires together, then wrap the connection in electrical tape. Repeat for the right wire to the black or negative lead.

Attach the brick connector on your solar cell to the brick connector on your motor or the hanging lead and test that the connection works.


LEGO brand solar cells are available as part of the eLab Renewable Energy Set. They can be found separately online or through LEGO's Education site under Resources.


Be careful when cutting electrical cables and wires. Never touch an exposed wire which is attached to a power source of any kind.