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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sjean3 made it!4 days ago
I made one that was this, then I am currently, soldering 5 seconds ago, making one that also has a crank charge too :). the advancement abilities to your project here are amazing and easy as pie.
BenH281 month ago

If you added more batteries ie. enough to make it to 5 volts would it still charge on apple devices

MicroCookie2 months ago
I realIy liked your project idea :) . So I wanted to ask if you can charge the phone battery when you have your solar panel and the batteries connected/active? Or can you only firstly charge AA batteries with your solar panel then turn off the solar panel and then charge phone battery from AA batteries?

If you can have all the components active at the same moment wount the solar panels 6v be too much for the charging circuit? The charging circuit can take voltage between ~2,6v and ~4,8v ( correct me if I'm wrong) . Would using a solar panel with lower voltage but with higher amperage solve this for example?
ANugget2 months ago

Hi, I just finished making the Solar USB charger and put in a new pack of rechargeable batteries. But when I charged it into my iphone 5s, it could only charge for about 7% before the small coil on the DC to DC Boosting Circuit with 5V USB Output (the red one not the Apple one) started to get really hot and made very weird noises. Does anyone know whats wrong with it? I checked my wiring and it doesn't seem to be wrong to have caused a short. Any suggestions?

Will this charger work with an iPhone 6?
ManjulaB5 months 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?

Cmwhitt045 months ago

how many amps does the apple circuit produce

i_ken_fly9 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_fly6 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.

Cmwhitt046 months ago

Does this work for iphone5 also because its a USB?

JoshuaZimmerman (author)  Cmwhitt046 months ago


ThumbSucker9 months ago
How did you make the board? Can I ask for a guide? Sorry im new
i_ken_fly9 months ago

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

apinnette210 months ago
While it is off does it still charge the battery
mcoleman131 year ago
Awesome! Looks like the ghostbusters ghost trap; ) we need more solar stuff! more more!
JoshuaZimmerman (author)  mcoleman1310 months ago

We're working on it!

landman121 year ago
If i wanted to buy one of these could i purchase one from you?
JoshuaZimmerman (author)  landman1210 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.

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_010 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.

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

Ha, not my phone!

jackbell161 year 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)  jackbell1610 months ago

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

gabbas11 year 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)  gabbas110 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!1 year 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 SMART10 months ago

Hot glue is the way to go. Looks nice.

Or anyone if they could answer
I promise I am not a narc
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?

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)  WW11371 year 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.

ekeesee1 year 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?


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