Introduction: Standalone Solar-to-USB With Battery

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This is how to put together a little solar setup that I use for demos. The panel charges a 12 V battery, which is converted to a 5 V USB output. In a video at the end, I show how I use it to power a small water fountain. As always, please be cautious of electrical and fire hazards associated with batteries and power sources like this solar panel.

If you share an interest in electronics-based educational projects related to physics, water use, and energy, it would be great to connect!

Step 1: Parts

(1) 15 W Solar panel - I used the Acopower HY015-12P (here on amazon)

(1) 12 V Battery - I used the EXP1270 from Expert Power (here on amazon)

(1) Solar Controller - I used this one

(1) Adjustable DC to DC Buck converter - I used the LM2596 (here on amazon)

(1) USB port - I used this one

(6) Fork terminals for connecting to the solar controller

(2) Quick Connect terminals for connecting to the battery tabs

In addition, wire and heat shrink wrap are needed for the connections

I found it nice to include a power switch, too

Step 2: Assembly

Attach the fork connectors to the 1) solar panel leads, 2) wires that will run from the controller to the battery, and 3) wires that will connect the controller to the load. Attach the quick connectors to the battery end of the wires going from the controller to the battery. Solder in connections from the controller to the power switch, then to the buck converter, and then to the USB port. [In my picture I have the switch and converter in the wrong order]

Plug the battery, solar panel, and buck converter in to the controller.

Step 3: Set the 12 V to 5 V Converter

Use the small adjustable screw on the buck converter to set the USB output voltage to 5 V.

Step 4: Enjoy Your New Solar Power Setup!

As shown in the photo, I mounted the components to a wooden board. [Here I have the switch and buck converter in the correct order]

One option is to use this setup to power a USB water fountain. I added some plastic conduit for waterproofing and placed the battery and controller inside a waterproof box with plenty of space so it keeps cool. In the video you can also see that I have it set up to power an Arduino (which can be used for wireless control of the load) or provide 120 V AC using an Energizer inverter.