Introduction: How to Make a Solar System for Your Bike That Turns on the Lights and Charges Your Smartphone

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About: I'm a 17 year old boy who loves doing projects from drones and arduinos to projects with wood in the backyard

Today I'm going to show you how to make a solar system for your bike that powers the bike's lights, front and rear and also has a usb output to charge your cell phone where there is no electricity or during your trail.

I had some lights for the bike, which worked with batteries, but they don't last long and so with these batteries I can have them on for much longer without having to recharge.

Let's see what is needed:

Supplies

  • 5v solar panel (3-10w)

  • Bike front and rear lights (You can replace with flashlights)

  • Two 18650 3.7v batteries or one 5000mah lipo

  • Step up convert from 3v to 5v with usb output

  • 3.7v battery charger

  • A small plastic box

  • Some wires

  • Soldering Iron

Step 1: Schematics and Soldering Batteries

The first photo is the circuit diagram that we are going to make. It's a very simple system and basically what works like this: The solar panel is connected to the battery charger that charges the batteries and the batteries turn on the usb converter that is connected to a switch and the same happens with the lights are connected to a switch which turns the current to the LEDs on and off.


Now we are going to solder the two 18650 batteries in parallel, that is, positive pole with positive and negative pole with negative, if it were connected in series the voltage would double and we don't want that because it would ruin our whole system

Step 2: Connecting the Battery Charger to the Solar Panel

This step is quite simple, just connect the positive and negative of the panel to the positive and negative of the battery charger (input) and connect the battery to the output of the charger.

Step 3: Install 5v Usb Converter

Now let's make an opening for the usb connector and do the wiring. Just connect the usb converter to the batteries and put a switch on the negative wire to not waste energy when we are not using it.

Step 4: Gluing the Solar Panel and Drilling Holes for Fixing to the Bike

In this step, glue the solar panel to the box cover and make the measurements for fixing it on the bike, which usually have a pair of screws to hold a water bottle or an air pump.

Step 5: Bike Lights Wiring

To make the connection, just connect the two wires of each light to the battery and put a switch. In the photos you can see how I did it.

Step 6: Connect the Wires to the LEDs

This step varies a lot for each person as each bike light is different but basically what I did was connect the wires directly to the battery connector and solder the switch to ON.

There are more information in the photos.

Step 7: Fixing

When everything is ready and working you have to arrange everything inside the box and fix it to the bike.

When it is well fixed, you can start winding the light wires around the bike frame to the desired place: one on the handlebars and the other behind the seat the red light.

Step 8: Finished

Now you have finished your project, in photo 1 is the cell phone connected to the charger. and in photo 2 and 3 you can see the bike at night with the lights off and on. In 4 and 5 you can see the light intensity which is quite good.