Solar Bluetooth Speaker With Powerbank

Have you ever looked at an old stereo or speaker gathering dust and thought, “I could make something cool with this”? 🌞

In this project, we’ll transform a vintage speaker into a solar-powered Bluetooth speaker that can also charge your phone or gadgets via USB. It’s a fun way to reuse old tech, learn a bit of electronics, and end up with a unique eco-friendly gadget.

Let’s dive in!

Main Components

1. 1 old stereo speaker (or any old portable speaker box) or you can buy one like this: Amazon / AliExpress
2. 1 Bluetooth audio module Amazon / AliExpress
3. 1 Lithium battery Amazon / AliExpress
4. 1 USB output module Amazon / AliExpress
5. 1 MPPT solar charge controller Amazon / AliExpress
6. 1 12V 5W solar panel Amazon / AliExpress
7. 1 On/off switch Amazon / AliExpress
8. 1 Battery indicator display
9. 1 Charging jack (DC input) Amazon / AliExpress
10. 1 Acrylic box for modules

Tools & Materials

1. Drill and jigsaw Amazon / AliExpress & Amazon / AliExpress
2. Soldering iron + solder Amazon / AliExpress
3. Hot glue gun Amazon / AliExpress
4. Marker and ruler
5. Small screwdriver Amazon / AliExpress
6. Spray paint (optional)
7. Diode (for solar protection)
8. Wires, terminals, and screws

Start by carefully opening your old speaker.

Remove everything you don’t need: cassette mechanisms, radio boards, old amplifiers, etc.

Keep the main speaker driver, since we’ll reuse it for audio output.

Once it’s empty, clean the inside thoroughly — remove dust, glue, or loose cables. You want a clean base before adding new components.

Now that the speaker is empty, we can prepare the hole for the Bluetooth module.

Measure the module dimensions, mark the outline on the front panel, and drill a small hole to insert your jigsaw blade. Cut carefully along the line and smooth the edges with a file or sandpaper.

🧠 Tip: Take your time with this step — a clean cut will make your final result look professional.

Let’s make space for the rest of the controls and ports. You’ll need holes for:

1. The USB output port (powerbank)
2. The main switch
3. The battery level indicator
4. The charging jack

Use the battery height as a visual reference to align the components. The acrylic box that holds the power modules can go a bit higher.

This layout keeps the power management section separate from the Bluetooth controls — but you can design your own arrangement if you like!

Don’t forget to drill two more openings:

1. One on top for the carrying handle
2. One on the side for the solar panel cable

Here’s the wiring diagram I used — it shows how each component connects (battery, modules, switch, and solar panel).

1. Start by soldering the charging module, USB output, MPPT controller, and switch.
2. Follow the diagram step by step and double-check polarity before connecting the battery.
3. Secure each module inside the acrylic box using hot glue.

⚡ Tip: Test each part before closing the box — it’s easier to troubleshoot with everything accessible.

Even if it looks a little messy, as long as the wiring follows the diagram, it will work fine.

Before connecting everything together, it’s important to properly adjust the output voltage of the MPPT controller to match your lithium battery. This step ensures the panel charges the battery efficiently and safely.

1. Connect the solar panel to the controller’s input terminals.
2. Use a multimeter to measure the controller’s output voltage.
3. With a small screwdriver, turn the adjustment screw on the controller until the output reads 12.6V, which is the correct full-charge voltage for a 3S lithium battery pack.
4. Move your hand over the solar panel to create some shade — you’ll see the voltage drop slightly and then recover. This is how the MPPT system works: it automatically adjusts to keep the output voltage stable even with varying sunlight.

💡 Tip: Double-check the polarity (positive and negative) before connecting the battery to avoid damage.

Once the controller is properly tuned to 12.6V, you can mount it inside the project box and continue with the wiring.

Now it’s time to make your speaker solar-powered!

1. Preparing the Solar Panel

Use a 12V 5W solar panel — it’s enough to keep your speaker charged outdoors.

Add a diode in series with the positive lead to prevent current from flowing back into the panel at night.

2. Mounting the Panel

Attach the solar panel to the top of your speaker box using small hinges.

This lets you tilt it toward the sun for maximum efficiency.

To adjust the angle, I repurposed an old radio antenna as a support arm — a simple and creative way to recycle parts!

Feed the panel’s cable through the hole you made earlier and connect it to the MPPT controller via a terminal block.

3. Fixing Components and Closing the Box

Once the panel is connected:

1. Mount the USB/charging module box.
2. Fix the Bluetooth module in place.
3. Add the switch, indicator, and jack.
4. Reinstall the speaker driver.

Finally, reattach the plastic top and grille to close the box.

4. Testing Everything

Before calling it done, let’s make sure it all works:

1. Plug in the solar panel and confirm that the battery is charging.
2. Turn on the switch and check if the Bluetooth module lights up.
3. Connect a phone to test the USB charging.
4. Pair your device and play music to test sound quality.

If everything works — congratulations!

And there it is — your very own solar-powered Bluetooth speaker with a built-in powerbank, made from an old stereo that was collecting dust!

Now you’ve got a gadget that not only plays your favorite music anywhere, but also charges your phone using free solar energy. No outlets, no waste — just clean power from the sun.

I hope that you enjoy it!

You can see this project in Spanish here