How To Make A Solar Car STEP BY STEP

Posted 1 year ago by Kami

If you are looking for a fun science project that will teach your kids about how solar energy works, then this article is specially made for you.

This guide will show you how to make a solar car that combines learning the value of solar power and the enjoyment of building a car yourself.

Don’t worry this is a step by step that will lead you to build a solar powered car yourself even if you don’t have any previous DIY experience. 


1. 3-volt motor

The size of the motor depends on how big we need our project to be.

For this exact project, we will make a tiny solar-powered car so a 3-volt motor with a speed of 15,000 rotates per minute (RPM) and a 0.29 A Current will be good enough.

We started with the motor because it’s the engine of our project, we consider it as the heart of the car.

The motor will consume the energy from the solar panel and use it to spin the wheels and move the car.

You don’t have to buy a new motor, just search for any old broken toy and you will find one.

After choosing the motor, now it’s time to know how much power we need.

Here is how to calculate it:

  1. The first step is to multiply the current (Amps) by the Voltage (V) to get the wattage (W), this step will let you know the power rating of your motor.
    Our motor ratingsfor this project is a 3-volt with a 0.29 A, so the power rating would be 3 * 0.29 = 0.87 Watt-hour.
  2. In case we want to add a battery to our solar car, we have to assume how many hours the car will run per day, so we can calculate how mbig the battery should be. So let’s assume the car will work for 2 hours per day 
  3. The third step is to calculate how much power we use per day :

Power of the motor X Number of working hours per day = Power needed each day 

So: 6 X 0.87 = 5.22 watts.

After doing the calculations, now we know that we need a solar panel that generates at least 5.22 watts per day and a battery that can store this energy, so you can use your solar car whenever you want even if there is no sunlight.

2. 3-volt solar panel

After choosing our motor it’s time to choose a solar panel suitable for this motor.

Let’s show you how to get the best solar panel for your project :

  1. We need to know how many hours of sunlight or panel will get, let’s assume it will get 2 hours per day 
  2. Now it’s time to divide the power of the motor we get per day by how many hours of sunlight does the solar panel get 

The power needed per day / The number of hours the panel gets per day = The power of the solar panel

Then, 5.22 / 2 = 2.61

So we need a 3-volt solar panel to do the charging process efficiently 

3. 3 Volt Rechargeable Battery (optional)

If you want to make your car work at night you will need batteries 

So let’s know how to pick the best batteries for our project 

Battery capacity = power generated by the solar panel per day/battery voltage

So: 5.22/3 = 1.7 Ah = 1700Ah

Therefore, we will need a 3- volt battery with 1500-2000 Ah. 

Note: make sure that the battery isn’t too heavy for the chassis that it will prevent the car from moving. 

If it’s too heavy try to change to opt for a higher RPM motor and a new solar panel suitable for this new motor.

3. 1N914 DIODE

The job of the diode is to make the current flow in one direction, which prevents the solar panel from any damage.

3. on/off switch

We are using this switch to control our car, by attaching this switch with the panel we can control when we can make the car move or stop it.

Tools to build the chassis


We are using it as the body of our car, you have to cut it in a suitable length using a hand saw or a cutter.

Rubber wheels/Bottle camps

If you don’t have any rubber wheels you can use bottle camps, make sure that all the bottle camps you have are the same size.

drinking straw

it plays a very important in the project because it connects our body with the wheels, and it holds the shaft which connects the two wheels

wooden shaft or stick

connects both the back wheels with each other and the front ones too

plastic wheel gear

To make the car move forward, the plastic wheel gear must be connected with the wheels and the shaft of the car, when the motor starts rotating that will cause the car to move.

Rubber Band

It connects the motor with the plastic wheel gear, so when the motor start rotating it causes the gear to rotate too so the car is moving forward

A stand for the panel

You can use another bottle camp and glue the panel on it, you can also use a ball hinge and it will be useful so you can direct the panel in the direction of the sun.

Other tools

  • Soldering Iron
  • Solder
  • Wires
  • Wire Cutter
  • Hot Glue Gun
  • Protective eyewear
  • Gloves

How to make a solar car STEP BY STEP 

STEP 1: Prepare your chassis 

In our project we are using cardboard so you have to cut it in a suitable length( how long you need your car to be), then it’s time for emptying the sides for the wheels. We can also use popsicle sticks instead of cardboard.

Cut two pieces of a drinking straw in a suitable length depending on how long your chassis, insert the wooden stick through the shaft.

Use the wooden stick to connect the two front wheels and another one for the two back wheels, then glue them in the chassis.

Insert the plastic wheel gear to the wooden stick, and then insert your rubber wheels or the bootle camps.

STEP 2: Attaching the motor 

Glue the motor to the solar car chassis, then connect the motor and the wheel gear using a rubber band.

STEP 3: Connect the solar panel to the 1N914 Diode

The 1N914 Diode has two ends, the red one and the black one.

The solar panel also has two sides: the red one and the black one.

Connect the two red ends and the two black ends.

STEP 4: Connect the motor and the panel to the battery 

Attach all the red wires for the motor, solar panel, and battery, Repeat the previous step but for the black wires this time.

Step 5: ON/OFF switch

Glue it to the side of your body in a suitable place where it can be easily reached.

connect the positive wire of the solar panel to the first terminal of the on/off switch, and then connect the second terminal wire of the switch to the positive terminal of the DC motor.

Step 5: Enjoy your car

Now you have attached everything so it’s time to try it on the road, just hit the ON switch and enjoy your car, make sure that you are at a sunny place.


A passionate solar energy engineer and environmentalist who loves to create content.