Picture of Solar USB Charger 2.0

Everyone has USB gadgets. It's pretty much a fact of life. Another fact of life is that these USB gadgets also continually run out of power when you most need them. No need to fear, solar power is here! Ditch those crazy wall adaptors, throw out the laptop, and start making your own solar charger!

One of the most popular projects for new Makers is creating their very own Solar USB Charger. While there are many right ways to do this, there are also many highly inefficient ways. In 2011 I posted designs on how to put a simple USB charger in an Altoids tin. While this proved to be a very useful and fun project that design hasn't held up well over time. With each new generation of cell phone or MP3 Player batteries get bigger and my original design proves to be less useful.

This guide will show you step by step instructions on how to make your own Solar USB Charger as well as files on how to make a nice looking laser cut wooden box. This charger will charge most small USB devices such as cell phones, mp3 players, iPods, and iPhones. These direction are designed to use parts from my Solar USB Charger 2.0 Kit though you can also find many of these parts elsewhere online. You can also choose to ignore the laser cut wooden case aspect and use a different enclosure, though I'd recommend not using Altoids tin anymore.

This project was designed for beginner Makers and students. It requires a base knowledge of soldering. While you can charge small gadgets, this project is not appropriate for camping or to be relied on for extreme emergencies.

Difficulty: Easy
Cost: Low
Time: 30 - 60 minutes

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gabbas11 month ago

Do I have to use this 1N914 diod, or can I use (nearly) any other? Go some electrical waste here..
What do I have to care when choosing the diod?

jgonzalez931 month ago
Or anyone if they could answer
jgonzalez931 month ago
I promise I am not a narc
jgonzalez931 month ago
Hey guys i need to know ASAP... I have created my own model of solar charger, i have searched up the patents on solar chargers and Tsann Kuen Enterprise Co Ltd seems to hold a patent for solar chargers have you guys received any threats since you sell your products?

so i have 4x 1.2v (= 4.8v)solar panels from those yard lights you buy from walmart they suck as lights but they come with a solar cell and rechargeable batteries so it can last all night (they dont) so im using them would they work or since you need 5v do i need to add another

each of my solar cells puts out 2.2v +- 0.2v so with the 4 i get 9v

so do i need all 4 and all 4 batteries or can i can i do with the 3 like you

oh by the way my batteries are the 2/3 aa the weird short ones but normal sized around

they just say this charger is not recognized and then charge anyways or atleast thats what mine did

landman122 months ago
If i wanted to buy one of these could i purchase one from you?
mcoleman132 months ago
Awesome! Looks like the ghostbusters ghost trap; ) we need more solar stuff! more more!
jackbell162 months ago
Thank you for share your project. I think you will be right to use a boost up from the Solar power to the USB. Anyway, you use the diode to drop the voltage from the solar power to the battery and not to let the current flow from the battery to the solar power, isn't it ?
mikathigga222 months ago
I like the bleach wallpaper on the phone in the pictures
SoHa SMART made it!3 months ago

Great instructable and a fun build. The only mods I made were hot glueing the battery holder, USB connection and solar panel on.

WW11378 months ago

How long should it take to charge? I left it in the window for about a week and it charged my phone (galaxy s3) for maybe 5 minutes before cutting out . While it isn't super sunny out, I expected a little more. Is that normal?

JoshuaZimmerman (author)  WW11373 months ago

Depends on many things. I've found that Galaxy S3 phones are tough to charge due to the fact they want 1A or more of power, plus they have huge batteries. For those phones you really need to use a Lithium Battery instead of AAs (plus the right protection on it).

Instead of foam two sided tape, i used a hot glue gun

Yup, that works just fine as well. Hot Glue is not conductive, though it is a tad messy.

ekeesee4 months ago

Would a DPDT center off toggle switch work? If so, are there pros and cons?

Thanks for putting this together! Can you please tell me what the the voltage across the USB pins before hitting the voltage booster would be?

Charly_ZA7 months ago

Hi, if I used a 12v lead acid battery would it be necessary to use a charge controller? How many AHR would be sufficient?


JoshuaZimmerman (author)  Charly_ZA7 months ago

You'd want to build a much much bigger setup if you were using a 12V Lead Acid. You'd want a big old 12V charge controller and a big 12V solar cell (18V actually).

nbaldan8 months ago

Would i do any changes if i do it for charging an Iphone 5?

Archimidious9 months ago
that's understandable, but in my case I need something lightweight and easy to pack around so its perfect, but to each his own.
JoshuaZimmerman (author)  Archimidious8 months ago

They're just limited in size and metal. A small plastic container would work far better and be far easier to waterproof.

dzulfaqar9 months ago
if i change the battery with battery size D 1.5v and 6000mAH. solar charge still works?
JoshuaZimmerman (author)  dzulfaqar8 months ago
You need to have rechargeable D batteries, regular ones won't recharge. If you have rechargeable ones it would work just the same, only it would take a much longer time to charge up as their capacity is greater than AAs.
Archimidious10 months ago
As I am in the army and need to keep in contact with people this is absolutely necessary for me I switched out the small solar panel for a 5w one and I fit everything into an altoids tin and it fits very nicely, as long as you layer the bottom of the tin with electrical tape you won't have any problems with shorts.
JoshuaZimmerman (author)  Archimidious9 months ago
True, I do love Altoids tins. They're just… not my medium of choice any more.
Archimidious10 months ago
I made this and I absolutely love it the efficiency rate I have calculated at ~90% +/- about 3% for error on my part
JoshuaZimmerman (author)  Archimidious10 months ago
Wow, nicely done!
highestshelf10 months ago
I only have a unused high school knowledge of circuitry, but would it be possible to make a solar charger that could be worn as a bracelet, similar to the wide copper ones popular in the 70's? I see charging bracelets, but they seem to be just battery packs that need to be separately charged.
JoshuaZimmerman (author)  highestshelf10 months ago
Sadly no. The problem is the amount of space the solar cell needs. Yes, you can find some "chargers" with super small solar cells. The issue is that they'd take weeks and weeks of full sun exposure to do any good. Putting one on your wrist would leave it in the dark most of the time.

Now making a backpack or jacket using super expensive flex solar cells, we can do that.
dupes88810 months ago
yeah why havent you
JoshuaZimmerman (author)  dupes88810 months ago
Why haven't you...... what?
astral_mage10 months ago
why havent u though of selling flexible solar panels by now on yr website. way easier to work with. an almost unbreakable as well.
JoshuaZimmerman (author)  astral_mage10 months ago
More expensive, lower output, lower demand from hobbyists. I've tested out several types, but they're not worth it for what I'm doing or the projects I'm making.

I could, but you'd be paying three times as much for the same output solar cell (that is also almost twice the physical size as well).
ferjanyen10 months ago
Hi and a very good project. sell it without box, it will do us a favour as we will have just you to obtain all the bits. Let us decide what type of box we like to use. Make it easy, just put the bits un buble wrap envelope and sed it, no fuss. I'l be the first one to buy one kit from you. thanks. Ferd.
JoshuaZimmerman (author)  ferjanyen10 months ago
All the parts (and more) are available on my site, you can grab whatever you'd like to make this project. Mix and match.

I made the wooden box because I've spent way too much time trouble shooting shorted out projects due to Altoids tins. Insane amounts of hours and replacement parts.
czhanacek10 months ago
Ah okay awesome. Also, is it possible to just use an LED as the diode? Of course, it'll use a bit more power, but that's all I've got lying around right now.
JoshuaZimmerman (author)  czhanacek10 months ago
That wouldn't be a good idea. There would be too great of a voltage drop. A simple 1N914 diode can be found nearly anywhere and are insanely cheap. Go that route.
The trouble with 1N914 (or 1N4148 or 1N4001) is it uses up almost a volt when you pass charging current through it. I'd splurge on a shottky type diode here. You lose less than half a volt. Shottkys leak more than Si P-N diodes like '914 but we don't care about that here. 1N5819 seems to be the "jelly bean" part. Anchor has them for 15 cents in hundreds, Mouser 40 cents each.

An LED would be terrible. You lose two or three volts across it because it's turning it into light.
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