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August 25, 2012 11:34 PM   Subscribe

How to build a Solar Mobile Charger in 5 minutes. Full instructions here.

Note that the charger is 5V, so it won't work for all phones.
posted by Deathalicious (36 comments total) 20 users marked this as a favorite

"11 solettes"

If I'm going to have to order something anyway, I'm pretty sure I can beat his time by four and a half minutes by clicking on amazon links for "solar cell phone charger"
posted by Tell Me No Lies at 11:43 PM on August 25, 2012 [12 favorites]

I looked, but could not find any mention of how long the charging time is supposed to be. How long does it take to get your phone (or AA battery, in the case of Deathalicious's link) fully charged?

Or is the phone thing not actually meant to fully charge a phone, instead just giving you the option to talk while your battery's dead and sunlight is handy?
posted by Sleeper at 11:55 PM on August 25, 2012

I'm not 100% of this, but in the phone's case I think it's suppose to serve as a source of energy for the phone but not sure if it charges the phone at the same time.

Apparently the "solettes" are from China & somewhat hard to find. I suspect they are similar to these "Commercial solar cells" which are $0.20 apiece. These guys are actually working on setting up a way to get them more easily in the States (did not link to that info since it's tied to a Kickstarter and thought the video was interesting enough on its own).
posted by Deathalicious at 12:04 AM on August 26, 2012 [1 favorite]

So basically this is about how to make a solar charger by getting solar panels and a charger?
posted by Pyrogenesis at 1:30 AM on August 26, 2012 [4 favorites]

Yep, kinda disappointing. Here I was hoping to see someone building circuit boards and making a solar panel from scratch and it was basically just "take one phone charger and some small solar panels, solder them together, and enjoy!"
posted by Mokusatsu at 3:30 AM on August 26, 2012

I see it as much more liberating. So you have:

- Lots of computing devices with low power requirements - 'phones and tablets.
- Mass-produced dirt cheap solar power cells.
- Basic cabling and wiring and soldering skills.

Cheap computing and communication for poor countries with poor infrastructure, essentially. I'm sure this is just something your local corner shop does in Nairobi.
posted by alasdair at 3:45 AM on August 26, 2012 [1 favorite]

Actually, after posting, another thought: who cares if it's not rocket science? We bemoan STEM education and how Youth Today doesn't understand the basics of electronics and computing. Let's celebrate fun little projects like this. Send it to your local youth group leaders!
posted by alasdair at 3:47 AM on August 26, 2012 [8 favorites]

That's yet another thing straight out of a cyberpunk novel. A reasonably smart guy has a handheld, battery-powered computer, which doubles as a wireless video telephone, with more computational power than mainframes used to have. It runs on batteries and, sadly, doesn't last more than a day or two without being plugged in.

So, using a scavenged plug with a couple feet of wire, a clothespin, a couple of pieces of metal, and eleven small pieces of wizard-class tech from China, he rigs up a solar cell to charge it when he's away from mains power.

And then he makes a video of it, possibly with a similar phone, and shares it on the worldwide data network. Hundreds of millions of people can see the exact process he used, for free.

I'm telling ya, folks, we are officially in the future. It has arrived. It is here.
posted by Malor at 4:53 AM on August 26, 2012 [20 favorites]

I am with the yay-sayers*. Ok, I don't have any of this stuff handy, but I had no idea how simple solar chargers were. I would totally try this from some salvaged crap. A few of those garden lights people keep throwing out, a charger from the bin of lost stuff at work... It's clear to me from this that the plastic/resin etc that the cells are encased in is purely supportive, not necessary to the function. I liked this, accessible!

posted by Iteki at 5:00 AM on August 26, 2012

"What an age we live in" aside, was this particular video useful to ANYONE? Seems like it kinda sucks.
posted by ShutterBun at 5:04 AM on August 26, 2012

Moving on... That soundtrack? (wrist to forehead) Horrid, I say!
posted by hal9k at 5:12 AM on August 26, 2012 [1 favorite]

I wonder if solar cells will be like LEDs were a couple years ago, when there was lots of web advice for getting cheap LEDs from products (christmas lights, cheap toys) for projects. I bet you could source some solar cells via some tchotchke like a calculator given away at a conference.
posted by 445supermag at 5:49 AM on August 26, 2012

He wasted an awful lot of paper right there. Not very green. Not very green at all.
posted by JeffK at 6:29 AM on August 26, 2012 [1 favorite]

I like this general concept, but I'm glad they are billing it as something for dumbphones (which don't require as much juice as smartphones). With such a small solar collecting area I don't think it would do much of anything to charge a fancier, more power-hungy gadget. And I don't think the little clothespin panels would provide enough power to allow someone to actually talk on any kind of phone without also being able to run down the battery (unless maybe you were experiencing the glorious solar power available on the planet Mercury).

The solar charger I built to use with an iPhone and iPad has a much bigger solar panel along with batteries to store the energy. When I was camping this summer, I left my charger out all day and then charged my gadgets when I got back to my tent. The charger was in full sun for more than 12 hours each day, and would build up enough charge to bring an iPhone up by about 50%.

The solar panel I used is so much bigger than the little clothespin panels that I don't think the little set of panels would much more than just keep the display powered up on a smartphone, if that. My charger has some losses from going through the intermediate battery, but it beats trying to keep the charger on the phone and in the sun all day.
posted by exogenous at 6:32 AM on August 26, 2012

So wait, you buy two things and break one of them so that you can put together something you can easily buy in the first place? Wasting a bunch of paper in the process and yet failing to mention that the polarity has to be correct?
Yay! The future!
posted by c13 at 6:32 AM on August 26, 2012 [2 favorites]

Well it is sorta cool that you don't have to solder the cells together- that part can be a real PITA. As for using scavenged cells from cheap calculators, he's using monocrystalline silicon cells in this project- you can tell by the color (blue). The cheap calculators and whatnot typically use amorphous silicon cells which are less powerful, so you'd need more of them, and would also have to run sets of them in parallel to get the current up where it can actually do some charging in a reasonable amount of time.
posted by Phyllis Harmonic at 6:58 AM on August 26, 2012

Moving on... That soundtrack? (wrist to forehead) Horrid, I say!
posted by hal9k at 5:12 AM on August 26

That never-before-seen camera angle with the fast-motion was making me feel like I was on a rickety roller coaster.
posted by Lukenlogs at 7:17 AM on August 26, 2012

I think you need a phaser and a visor to do this. Without those, you'll never get your communicator working properly.
posted by cjorgensen at 7:36 AM on August 26, 2012

Nokia did a study on solar cell phone charging, showing that solar charging is still really, really impractical.

How impractical? In the desert, near the equator, it took twelve hours of charging with the device off to get 20 hours of use. With a "dumb phone".
posted by fake at 7:57 AM on August 26, 2012

Well, it's impractical when you are surrounded by wall sockets. When you're off the grid without a generator, it's another story though.
But that applies to all other uses of solar charges, not just charging phones.
posted by c13 at 8:09 AM on August 26, 2012

"What an age we live in" aside, was this particular video useful to ANYONE?

It seems to have demystified solar cells for Iteki. Does that count?
posted by pompomtom at 8:31 AM on August 26, 2012 [1 favorite]

It seems to have demystified solar cells for Iteki.

Ah, but wait till he sees what happens to the phone when the charger gets shaded for some reason.
posted by c13 at 8:35 AM on August 26, 2012

Nokia did a study on solar cell phone charging, showing that solar charging is still really, really impractical.

That's not what your link shows at all. It shows that solar cells only on the phone can keep your 'phone alive indefinitely, but you'll have to charge it to make calls. Again, that's solar cells only on the phone. Not a separate charging panel, which has been the subject of this thread.

Did you mean to link to a different study, or have I misunderstood the study?
posted by alasdair at 8:53 AM on August 26, 2012

This thing, will let you charge your USB stuff with FIRE. Which seems a little more convenient than depending the sun if you're going to insist on leaving the abandoning grid electricity.
posted by ambilevous at 9:18 AM on August 26, 2012 [1 favorite]

Well, none of these things are as convinient as plugging in. So the more different sources of power you have-the better. I have the biolite stove and it works pretty well, but for charging you need to keep it hoing for quite a while. If you drape a solar panel over the backpack and let it charge a battery pack during the day, and add to it the power from biolite when you cook, thungs get that much easier.

In addition to biolite, there's also PowerPot that you can harvest additional power with.
posted by c13 at 9:53 AM on August 26, 2012 [1 favorite]

I checked out the Biolite website and was very disappointed that "Charge your devices with FIRE" was not their corporate motto.
posted by Tell Me No Lies at 10:08 AM on August 26, 2012

That Nokia article is pretty poor, no details on what they did and the link to Nokia is broken, so I have no way to tell if it was a good experiment or not. I know folks in Silicon Valley that are making cheap high efficiency cells that can easily keep a dumb phone charged - using just the back-side of the phone. The target market is the developing world.

The FPP video is pretty impractical, but it should serve to illustrate how simple solar cells really are. They're just diodes (like LEDs). When they're stacked together like that, you're creating a series circuit of diodes. You get about half a volt from each cell, so stacking 11 give you a little over 5 volts. The cells shown are cheap basic multi-crystalline cells that you can buy easily. There's no China magic there - this type of cell has been produced for 30 years.
posted by Long Way To Go at 10:18 AM on August 26, 2012 [1 favorite]

"The cells shown are cheap basic multi-crystalline cells that you can buy easily. "

You're correct and I was wrong- these are definitely NOT mono-crystalline (as I too-hastily commented- serves me right for posting before all systems are at least nominal.)
posted by Phyllis Harmonic at 10:31 AM on August 26, 2012

I tried to rig up a solar charger for a kindle a couple of years ago. Turns out it was really very picky about exactly what current was fed to it, and a simple charging circuit like this just wasn't ever going to work. All the phones we tried took charge just fine though, no problems there.
posted by Chuckles at 2:41 PM on August 26, 2012

Could you combine different sources, use them at once and cut down on charging time. Like a diy solar source, and a diy wind source, and a diy bike-powered source and a diy hand-crank source. Two people, some wind, some sunlight. I'm not saying it's practical for us here, but in extreme off-grid situations where people have time and no money and no access to a power grid.
posted by marsha56 at 3:21 PM on August 26, 2012

Of course. Even better if you put a car battery in the middle so you can store the energy.
That's similar to what people use on small yachts (well, at least wind and solar. I haven't yet seen TEGs used yet.)
posted by c13 at 3:41 PM on August 26, 2012 [1 favorite]

Nokia did a study on solar cell phone charging, showing that solar charging is still really, really impractical.

Didn't read the Nokia link, but that conclusion sounds wrong.

From personal experience I know that solar charging can be very practical, especially for smaller devices. I don't know where to get the 'solettes' shown in the OP, but I regularly pick up useable 12v solar panels on sale (eg a 12" x 5" panel with near 1W output for like $10). This sort of panel sometimes requires a circuit to step down the panel's higher voltage to the correct charging voltage, or if your device has a USB charging cord, you can easily find auto cig. lighter to USB adaptors for $5.

Another source of cheap solar cells is those solar garden lights you see everywhere. It would take more soldering but a few of these cells might charge a phone.

We use a weatherproof 5W solar panel ($40 on sale) to top up our small boat's battery when we're anchored, and I'm currently putting together a high-efficiency 12v to 5v converter (using LM2575) for powering and charging USB-powered devices like my wife's iPhone when we're away from power.

marsha56 - yes, it's not hard to combine sources. Usually this is implemented by having all the different charging sources charge a battery (or a battery bank), with circuitry to prevent conflict or draining.
posted by Artful Codger at 3:45 PM on August 26, 2012 [1 favorite]

... or what c13 just said.

posted by Artful Codger at 3:46 PM on August 26, 2012 [1 favorite]

Because solar panels of limited sizes generates so little energy, one would really want an intermediate storage device - if nothing but to provide a sink to power something else that will clean up the charge and provide constant voltage and amperage.

Chuckles - I'm super surprised that the phones picked up charge from unregulated trickle - I wonder what long-term charging of this type will do to the battery.

Electricity is fairly easy - been known since ancient Greece - but powering/recharging our modern devices is a little bit more tricky.

I really really wish Nicola Tesla got more backing (financial, political, and mental health) than he received while he was still of this world.
posted by porpoise at 8:53 PM on August 26, 2012

How about hand-cranking? There are several hand cranked phone chargers on the market, but the only one I tried (the ETON radio/flashlight/solar/crank) doesn't deliver power smoothly enough. Seems to me like a squeeze handle + flywheel + battery + voltage regulator would do the trick. Has anyone had any success?
posted by whuppy at 7:03 AM on August 27, 2012

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