Solar USB Charger

By Steve Hobley
Category: Computers & Mobile, Electronics
Time Required: 1 hour
Difficulty: Easy

Charge up your USB devices with the power of the sun. By adding a small solar panel and two diodes to a standard USB cable, you can plug that cable into USB devices needing a recharge. It’s so easy. Let’s get started.

The Solar USB Charger being tested on a sunny day

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Steps

Step #1: Hack the cable

Cut one end off of a USB extension cable.
Cut away the cable's outer insulation and isolate the power lines. These are the red wire (+5v), and black wire (Ground). Strip the ends.
The solar panel already has corresponding red (+) and black (-) wires.

Conclusion

If there's one thing we have in the US, it's sunlight. And where I live, the summers can get incredibly hot. It's a shame to let all of that free energy go to waste, and this project shows you how easy it is to put that solar power to use.

8 Responses to Solar USB Charger

Nick Normal on April 15th, 2012 at 2:41 pm said:

Sorry there isn’t one currently available – but it’s really only two diodes and two cables, so I hope the pictures alone are enough to follow along with.

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Steve Hobley on June 8th, 2012 at 11:46 am said:

I would check to make sure the charger isn’t shorting out http://en.wikipedia.org/wiki/Short_circuit

Are you charging an iPhone?

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blanket on June 8th, 2012 at 6:09 pm said:

i’m charging a samsung phone with android running on it.

i’ve used a multimeter to check the voltage across the different components, and i’ve also tested it in the same way as in the last picture above. when the sun is steady, it produces a voltage right around 5V.

i’m fairly new to electronics, so i’m not sure if there is another specific spot to check for a short, or if there’s something else i should utilize on my multimeter?

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blanket on June 8th, 2012 at 6:12 pm said:

oh yeah, i’ve also tried to ensure that all the wires and components are well insulated from one another when testing, so there shouldn’t be a short in that way.
would the test in the last picture above work if there were a short, or would it produce a different result?

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Nick Normal on July 19th, 2012 at 4:55 pm said:

hi Blanket, sorry for the slow reply. Do you have a multimeter of any kind, to see where you are getting signal and where it is falling off?

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Frank Carter on November 18th, 2012 at 4:52 am said:

@ blanket – “i bought all the parts linked to, with the exception of the 25 pack of rectifier diodes. this wasn’t available, so i bought some 1N4001 diodes”
The 1N4001 is not a zener diode and blocks voltage. Zener diodes limit voltage. In this case, substitution is not allowed the part you have does a different job.

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blanket on January 29th, 2013 at 4:02 am said:

@Frank Carter – I subbed in a diode from the 1N4001 pack for the rectifier diode in the relevant parts list, not the Zener diode. It turns out my phone needed a larger solar panel (2 panels actually), since this setup made it act as though it were charging but really didn’t provide enough power (i.e. wattage). Having it in this “charging” mode drained the battery more quickly than if it had simply been idle.

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sbicy on May 22nd, 2013 at 10:20 am said:

Hey, can I do this with an iPhone 5 charger? Does this have to be done with a dual end USB, or can I do this with anything that charges via USB? (This may be a dumb question, but I am totally new to the Make culture and this will be my first project – father’s day gift for my dear ol dad…
Thanks in advance for any help and advice!

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