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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ManjulaB1 month ago

I am using a 4.7V, 500mW, 120mA solar panel. This is supplying three 1.2V(x3=3.6V), 2100mAh AA batteries through a 1N914 diode. The output of my battery pack is supplying a DC-DC boosting circuit with USB output. I am getting an output of 5V. But when I connect my phone to the USB port, the charge percentage goes down. What can I do about it? Is my current or power not enough?

Cmwhitt042 months ago

how many amps does the apple circuit produce

i_ken_fly5 months ago

also, when i charged my iphone with the apple circuit, it didnt charge. But when i used my android, it worked BUT it only showed that its charging but the battery actually went down, please help

JoshuaZimmerman (author)  i_ken_fly3 months ago

Make sure your batteries are all charged up. Also, some phones draw more power than the USB circuit puts out. They are CHARGING but their percentage goes down since they're using more power than you're putting in.

Cmwhitt043 months ago

Does this work for iphone5 also because its a USB?

JoshuaZimmerman (author)  Cmwhitt043 months ago


ThumbSucker5 months ago
How did you make the board? Can I ask for a guide? Sorry im new
i_ken_fly6 months ago

hi, i was wondering what are the dimensions for the laser cut box. If you can reply, thanks

apinnette26 months ago
While it is off does it still charge the battery
mcoleman1310 months ago
Awesome! Looks like the ghostbusters ghost trap; ) we need more solar stuff! more more!
JoshuaZimmerman (author)  mcoleman137 months ago

We're working on it!

landman1210 months ago
If i wanted to buy one of these could i purchase one from you?
JoshuaZimmerman (author)  landman127 months ago

Thats the idea. We have kits, and we highly recommend you building one on your own. It was designed for middle school students to learn how to solder with.

Divisible_By_010 months ago

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

JoshuaZimmerman (author)  Divisible_By_07 months ago

The big issue isn't the voltage, it's the amperage. Thats what will determine how fast things charge up. Typically the ones out of garden lights are super low amperage. You'll be waiting weeks to charge up the internal batteries.

mikathigga2210 months ago
I like the bleach wallpaper on the phone in the pictures
JoshuaZimmerman (author)  mikathigga227 months ago

Ha, not my phone!

jackbell1610 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 ?
JoshuaZimmerman (author)  jackbell167 months ago

It's to prevent the solar cell from sucking power from the battery, which would destroy the solar cell.

gabbas19 months 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?

JoshuaZimmerman (author)  gabbas17 months ago

Pretty much. 1N914 is super common and cheap, and has a low voltage drop. Thats why we use it for a lot of our projects.

SoHa SMART made it!10 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.

JoshuaZimmerman (author)  SoHa SMART7 months ago

Hot glue is the way to go. Looks nice.

jgonzalez939 months ago
Or anyone if they could answer
jgonzalez939 months ago
I promise I am not a narc
jgonzalez939 months 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?
Divisible_By_010 months ago

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

WW11371 year 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)  WW113711 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.

ekeesee11 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_ZA1 year 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_ZA1 year 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).

nbaldan1 year ago

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

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)  Archimidious1 year ago

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

dzulfaqar1 year ago
if i change the battery with battery size D 1.5v and 6000mAH. solar charge still works?
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