# Five minute solar phone charger

Need to charge your phone?  Have nothing but a clothespin and some P-N junctions?  Have no fear!  The (solar) power is in your hands!

## Step 1: The Big Idea

So, what's the plan, stan?

Well, we're going to make a solar panel from scratch that can charge up a simple phone.

See, cheap phones like mine are real simple to charge--they just need 5V and they'll take care of the rest.  They'll draw as much power as they can (my little nokia will draw up to an amp while charging), but they're smart enough to limit their current draw to whatever the source can provide.

So, that means we need to make a 5V solar panel.  Solar panels are made by wiring up a set of solar cells--big silicon P-N junctions.  A solar cell puts out a very low voltage--0.65V open-circuit, or around .55V under an ideal load.  To get the 5V that we need to charge a phone, we have to wire up a bunch of solar cells in series.

But how many solar cells?  Well, a solar cell without anything connected to it will produce .65V in bright sunlight, but as I draw power from the cell, the voltage will drop.  This relationship is called an I-V curve.  The max current the cell can output is based on the area of the cell, the intensity of the sunlight and the temperature of the cell, but the max voltage is always the same, regardless of the size of the cell.
Every solar cell has a peak power point, a current-voltage combination that gives me the most possible power for that cell.  For my panel, I want to run my cells at their peak power point.  I happen to know that the peak power point of my cells is .5V at 130mA.  So, if I want to put out 5V, I need to stack up at ten solar cells in series, giving me an output of 5V.  If I'm drawing less than 130mA, my output voltage will "float" up, and if I draw more, my voltage will get pulled down.  Now, it so happens that phones are pretty smart and robust, so I can actually give them a bit more than 5V, and they'll be fine.  I'm actually going to add an extra cell, giving me a total of 5.5V coming off my cell.  This makes my panel a little more robust--the higher voltage means that, in lower light, it'll still put out enough voltage to charge up my phone, and it'll be less sensitive to shading or pointing it away from the sun.

So, I'm going to make a solar panel with eleven solar cells in series, I'm going to wire the output into a phone, and it's going to charge.  Cool, right?  It's pretty quick and easy to do, too.  Here's a video of the whole process:

 1-40 of 73 Next »
Cris JohnM1 month ago

its a song from a Filipino band..are you a filipino?

prank (author)  Cris JohnM1 month ago
nobody's perfect
Ploopy1 month ago

Cool!

eknath.naik.1697 months ago

the video was very fast dude cant u write it instead of video

abhinavonowinew8 months ago

Hey Prank! From where to get such thin solar cells?

RyleeF11 months ago

Congratulations! I'm gratified you have discussed this particular essential information beside me. Many thanks!

owald12 years ago
Mobile phones have become a necessity, needing frequent charging thereby consuming a lot of electricity and consequently leading to time without contact. After extensive research, EC Trading offers unique iPhone 5 Solar Mobile Phone Charger with sufficient battery backup. When fully charged, the Solar Mobile Charger can be used at any time for charging any type of mobile phone.

Retailing at a fantastic £39.77 this fully featured case has a higher spec and more connectivity, than solar chargers costing twice as much. And for added convenience, the iPhone Solar Mobile Charger can be added to the pack, giving access to charge the unit in over 180 countries!

Lasting up to a brilliant 1100 hours on a single charge, and a massive 3000mAh extended battery the iPhone Solar Charger case has been extensively tested and re-engineered to include all the necessary accessories straight out of the box, The iPhone Solar Charger Case is a great way to keep safe and not have to worry about your iPhone losing battery when you are away from home.

Tak Lai, founder and MD, said: “It‘s great to present this product. After working to perfect, we feel we have a finely tuned product ready to meet the needs of the mobile consumer, with the widest selection of compatibility at an unrivalled price-point.”

Effective Capital Trading Ltd is one of the leading suppliers of innovative gizmos and gadgets.They also have a wide base in Solar related technologies. It's headquarters are in Hampshire and has various international offices that sell its listed products globally.
1 year ago

After a rudimentary search...http://www.scamwarners.com/forum/viewtopic.php?f=34&t=75520

kornedo1 year ago
kano ung copper tape?? tsaka..bilang cell gamt mo
echauz992 years ago
where can i buy the solar cells??? ps i live in manila
sanchitkhera72 years ago
Any chance of damaging the mobile phone? Does it work for smartphones too?
contactscolored2 years ago
I am fairly new to Instructables so I will have to take a look at putting it together. I definitely want to get a video up. I'll let you know when I get either up. (I tried replying but the captcha thing seems messed up)
Fhev2 years ago
sir, anu pa pwedeng ikapit sa clip bukod sa copper tape? anu ba pwedeng applicable bugod sa copper tape? pwede din q ba gamitin ang universal charger cable? iisa din lng ba xia? kung saka sakaling ganun gawin q, mas mgnda diba?
JensonBut2 years ago
I made these last night and the were delicious BUT the flattened out...
Gigean2 years ago
Is it possible to do make this for a smartphone? Is it recommended? I'm looking for a way to safely charge my Android phone
prank (author)  Gigean2 years ago
Sure! The charger I make in the instructable just outputs 5.5V at ~100mA. If you slap the appropriate USB connector for your smart phone onto the alligator clips, there's a good chance it'll power it up. It depends on your smartphone--some phones will be more finnicky about their power, but you won't hurt it. I say give it a shot!
prank (author)  Gigean2 years ago
Sure! The charger I make in the instructable just outputs 5.5V at ~100mA. If you slap the appropriate USB connector for your smart phone onto the alligator clips, there's a good chance it'll power it up. It depends on your smartphone--some phones will be more finnicky about their power, but you won't hurt it. I say give it a shot!
rimar20002 years ago
Very clever design!
lwillen2 years ago
jesus-i cannot see the clip because in germany it is blocked because of music copyright
prank (author)  lwillen2 years ago

It's the same video, but with creative commons music. Another guy, also from germany, had the same problem. I learned my lesson--all movies I put up from now on will have cc soundtracks.

--me
SelkeyMoonbeam3 years ago
Super cool!
3 years ago
Can't wait to do that tomorrow. Every day sun in the Philippines. (almost every day). But the problem the solar panel.

Thanks.

"...or stay tuned for a DIY solar kit kickstarter my friend and I are launching soon"
when???????????
prank (author)  Paulus443 years ago
Saan nakatira ka sa pilipinas? Nakatira ako sa maynila!

Kickstarter kit is coming August 15.
3 years ago
Hey cool you're in the Philippines?

Where can I buy them here? I'm in Bohol but I'm willing to get to Cebu or Manila to buy a bunch of these and make with my friends and family here. What Filipino doesn't use these Nokia phones? lol

Salamat!
prank (author)  filipeanut3 years ago
Hey Filipeanut,

We're running a kickstarter right now, and kits of solettes are one of the rewards. Check it out at http://www.kickstarter.com/projects/alex9000/the-solar-pocket-factory-an-invention-adventure.

Salamat naman!
3 years ago
Im from Netherlands and live here. Only english pls.
Thanks
3 years ago
Translation of the above. "Where do you live in the Philippines? I live in manila!"
3 years ago
I do live in Cagayan de Oro but this week we have a lot of clouds and rainy days. Anyway I have already the solarcells, but the coppertape was more difficult. But I found some scrapcopper and can use that. Tomorrow I make it and there are already some people from the mountains who will buy one.
I also read in the newspape that there there is a T-shirt what has a special procedure and it also work as a charger when you wear it. A wire from the T-shirt to your cellphone and your CP will be charged via your t-shirt.
Amazing.
3 years ago
I live in Singapore! Sun everyday too!
gemtree3 years ago
The copper foil tape can be found where they sell stained glass supplies, usually in different widths.
brintxin3 years ago
Tremendous instructable!

Please does anyone know wher to buy these wafers ? - I just can't find an outlet on the net.

Thank you.
prank (author)  brintxin3 years ago
The ebay link from the materials page shows a bunch of places you can buy them. And we're releasing a kit on kickstarter in two weeks. Stay tuned!
3 years ago
Thanks, but on the display I cannot see a materials page. I only see photos and the text and their are no links there.
I look forward to the kit.
prank (author)  brintxin3 years ago
Here you go--I should have made this an actual link. http://goo.gl/C25he

You can get the solettes from various guys on ebay, taobao, aliexpress, or anywhere else you search for "solar cell piece"
noahh3 years ago
If anyone is looking for copper tape, it's often sold at hardware stores in the pesticide section because it repels slugs.
mysss3 years ago
Awesome. So I take it a smart phone would likely be less robust?
chantie33 years ago
Do you think this would work safely and not break my iphone4? Thanks, Mary
3 years ago
Hi Mary,

This project won't "break" your IPhone as the iphone will simply say charging device not recognised. this project currently won't work for newer iDevices as they require a special circuit.

To quote Chunkyhampton
"Actually, charging Apple's devices is a little more complex than just supplying 5V on the USB port. You must also tell the device how much current to draw. This is done by supply a potential to the D+ and D- lines, using a couple of resistors.
This was reverse engineered by and is explained in detail by Lady Ada here:
and also a bit on my attempts at doing it here:
http://www.re-innovation.co.uk/joomla15/index.php?option=com_content&view=article&id=167:voltage-regulators-a-go-go&catid=48:blog&Itemid=75"

So yeah hope this helped
graghavendra3 years ago
actually these solar cell's are available which require for charging and all, at various sites,

dealsbookie.com, ebay.in also one of the sites where you can get solar cells
6v 100ma, 6v 200ma, 7v 100ma, 3v 100ma
resin laminated, cabinet, small kit, soldered with clip all available at just 4-6\$

can charge mobile phone by that, even can charge AA AAA batteries, can make solar lantern's and all
prank (author)  graghavendra3 years ago
You can definitely buy pre-made solar panels anytime you like. This instructable is about a different way of making them yourself. It's not a replacement--it's an alternative for anyone interested in what goes inside those pre-made panels.

I started experimenting with making my own small solar panels after I was dissatisfied with the existing resin-laminated panels--I was finding panels with shorted solettes, putting out a lower voltage than I needed, the resin would yellow in the sun after a couple years, making the whole panel unuseable, and after looking into how the panels are made, I started wondering if there could be a better way to make them.

Now, I'm not claiming that this instructable is a better way to make solar panels. There are plenty of flaws with the fanned design I used here. But it's just cool to make your own solar panel from scratch, and I put this instructable up to share that coolness.  Because making something yourself is always more interesting than buying it.
 1-40 of 73 Next »