Instructables

Solar Altoids iPhone/ iPod Charger

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Picture of Solar Altoids iPhone/ iPod Charger
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I love my iPhone 4 to death.  I really do.  Even if it sucks juice faster than a 1st grader at snack time and I often find myself on low power with a long train ride ahead of me.

I originally made my Altoids USB Charger to use with my iPhone, only to find that Apple being Apple doesn't let it's products play nice with generic USB chargers.  I then set out on a long journey to find a cheap charger that would work with an iPhone 4.  After sacrificing many a cheap Chinese charger to my garbage can I eventually found a great little circuit with the added bonus of having a retractable cable.

It's a cheap and easy project to put together and a great gift to give.

*** Update:  I've since retired this kit.  It's not held up over time very well.  I've done an updated version called Solar USB Kit 2.0 and a more rugged version called Lithium Heavy Duty 2.0.  If you're looking for something pre made, especially for camping or emergencies, you should try out one of our Folding USB Solar Cells.  They're inexpensive and much much more powerful than what you'll find here.

Time: 30-60 minutes
Cost: Under $20
Difficulty: Easy
 
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Step 1: What You Need

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Parts:
Charging Circuit
2x AA Battery Holder
2x Rechargeable Batteries
1N914 Blocking Diode
Solar Cell greater than 4V
Stranded Wire
Tape

Optional:
Altoids Tin

Tools:
Soldering Iron
Solder
Hot Glue Gun
Wire Strippers
Protective Goggles

If you're interested in this project I have kits available on my website, browndoggadgets.com, that have everything you need to make the charger.  If you're not one for making things I  sell premade chargers as well. 

More than 12% of all profits go to dog and kitty toys.  You wouldn't make a kitty cry, would you?

Step 2: The Charging Circuit

Picture of The Charging Circuit

For this project I've stolen a charging circuit from an Emergency iPod charger I got off ebay.  You can find these all over the place.  The key is to find one that will work with an iPhone.

Apple decided to have it's newer iDevices not follow USB standards.  When an iDevice is plugged in it checks the data tabs on the USB to see what it's plugged into.  Depending on what it finds it sucks more or less power, which makes sense but is annoying because NOTHING ELSE DOES THIS.  Thus no charger out there has any power flowing to the data tabs.

So the key is to find one that works for your newer iPod or iPhone.  If you have an older iPod or iPhone when you don't really need to worry all that much.

(For a USB Version of this, check out this instructable.)

If you want to make your own circuit you can always use a Mintyboost kit.

Step 3: Batteries

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What I really find annoying is that on all the commercial solar chargers I see their internal battery is only 1000 mAh. That isn't a lot. A rechargeable AA battery has between 2000 - 3000 mAh of current in it. We can do better.

We need to use rechargeable batteries for this project. I prefer NiMh AAs over everything else because they're easy to find, cheap, and reliable. You probably even have a few at home. Since we're using two AAs in this project our charger will have 2000 - 3000 mAh of current. You could even have two sets of AAs in parallel and boost that capacity to 4000 - 6000 mAh.

An added bonus from rechargeable AAs is that you can take them out of the Solar Charger, charge them up or replace them, and be on your way. 

Find some cheap ones and use them.

Step 4: Choose Your Solar Cell

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If we use two rechargeable AAs that put out a total of 2.4Vs we're going to need a solar panel that is at least 3 - 4Vs just to meet basic levels of charging. The higher the voltage of our solar cell (or cells) the less light we need to charge up our batteries.

Now we're also trying to fit this into an Altoids Tin, so we're limited in space. I have found some great 4V solar cells that perfectly fit into Altoids Tins. They're the same ones I use with my Solar AA Atoids Charger.

Sure, a bigger and better solar cell would give us added power, but it wouldn't fit into our tin. (Something that has annoyed me with nearly every Altoids Solar Guide out there.)

You could also use a combination of several smaller cells to get your four volts. For example, 2V cells are very cheap and small on ebay. You could easily connect two of those in a series to get your 4Vs.

Just remember that when charging NiMh batteries we don't want to throw more than 10% of their capacity at them at any one time. For instance if your battery has a capacity of 2000 ma we can only use a solar cell that puts out 200 ma or less of current. This isn't usually a problem unless you're using a massive solar cell or a big combination of cells. None the less, keep this in mind.

Now if you're not using an Altoids tin you can always go crazy with a big solar cell.  As you can see in the picture I have a lot of cells to choose from.  Variety is the solar cell of life.

Every cell pictured above is available on my website, browndoggadget.com.  Great for all sorts of fun projects.

Step 5: Strip Your Wires

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First strip your wires. 

Cut off 1/3rd of the wire from the battery holder and then strip some coating off the end.

Now cut a couple lengths of wire about 8 inches long.  Strip the coating off each end.

Done!

Step 6: Solder The Solar Cell


First wrap one of your 8inch wires around your diode.  Look at the diode.  One side has a black bar.  This is the negative end.  Wrap your wire around that end.

Then just solder the wire to the negative end of the diode.

The positive end of the diode should then be soldered to the solar panel's positive tab.

Use your second wire on the negative point on the solar cell.

Step 7: Twist Up

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Take the red wire (positive) from the battery pack and twist it together with the positive wire from the solar cell.

Take the black wire (negative) from the battery pack and twist it together with the negative wire from the solar cell.

Don't solder.  Seriously don't.  Go get a cup of tea and relax.

Crazy fools.

Step 8: Solder The Circuit


This is the most difficult part of the project.

Look at the circuit.  You should be able to find a Positive (+) and a Negative (-) point on it.  Just look for the battery tabs.

Now you don't have to remove the battery tabs, you can leave them where they are.  Usually they are very easy to break off and it does save you some space.

Now just solder the positive cluster of wires to the positive point on the board, and the negative cluster of wires to the negative point on the board.

Now the big problem I see people having with projects like this is that they use too much solder.  Lets refresh how we solder so we don't cause any shorts.

Touch your soldering iron to the wires and wait five seconds.  Then touch the solder to the wires.  DO NOT directly touch the soldering iron with the solder.  The goal is to heat up the wires.  When they're hot enough the solder will flow nicely.

You don't need a lot of solder to get the wires to stick.  Just a dab. 

Step 9: Tape Things Up


Now that we're all done you can tape things up.

Use some electrical tape and tape up your solar cell.  Cut off any extra diode or wire.

If you're using a tin it wouldn't be a bad idea to tap up the area where you're going to put the circuit.  Just on the off chance that you might get a short because of the tin surface. 

The top right corner is a good spot. To put the circuit.

Step 10: Glue It Down

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BUT WAIT!  Before we glue down why not test out the circuit to see if it's working?  You can even just throw in some regular AA batteries to see if everything is charging up well.

Throw some hot glue down on the far left side of the tin where your battery holder will be.  Then, put the battery holder down. 

TAKE BATTERIES OUT BEFORE YOU DO THIS.  Otherwise they'll probably get glued down as well.

Now throw some glue down where you want your circuit to be.  Place the circuit on top of it and hold it down.  You want it as far back as you can in the tin.

Once the glue is dry we're going to go back for Round 2.  We want to make sure the retractable cable is nice and secure.  I usually scrunch the cable into the back corner and then throw down a whole lot of glue over the top of it.  This was I don't have to worry about pulling the cable off.

Once that's dry you're totally done.


Step 11: Before Using

Before you start using the charger you should do a couple of things.

1st, charger up the batteries.  You can do this either through large amounts of sun or by using a wall charger.

I've found that if the batteries get low on power the iPhone will throw out an error message saying "Not compatible for charging with iPhone" and then refuse to charge.  Just charge up the batteries again and life will be good.

2nd, figure out how everything fits in there.  The retractable cable will lay flat on the bottom if you've got everything spaced out correctly.  The solar cell will also fit inside the tin. 

If you're having issues with the solar cell try turning it around clockwise.  This bunches up the wires and allows for it to fit in a bit better. 

It can sometimes be a tight fit, but believe me, everything fits.

3rd, if you're having issues with your iPhone or iPod and charging try using some regular batteries.  If they work then that means that your rechargeable batteries just need a recharge.  Also keep this in mind.  In a pinch you can always throw in regular batteries to charge up your phone.  Like if zombies are attacking at night.

Step 12: Enjoy!

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And you're done.  Easy as pie you bought from the grocery store because you don't know how to make pie.

The only downside to this project is that you can't get an iPhone to charge directly from the sun.  Our little solar cell just doesn't put out enough current to charge up the iPhone.  Sadness.

If you're interested in the project I do have kits on my website available, as well as all the parts you might need for making a similar project.

Its amazing what you can do with a couple of solar cells and batteries.  Plus things like this make great gifts.

*** Update:  I've since retired this kit.  It's not held up over time very well.  I've done an updated version called Solar USB Kit 2.0 and a more rugged version called Lithium Heavy Duty 2.0.  If you're looking for something pre made, especially for camping or emergencies, you should try out one of our Folding USB Solar Cells.  They're inexpensive and much much more powerful than what you'll find here.

VidDroog2 years ago
Thorough and well thought out instructions...as would be expected from a teacher..

Appreciate the explanation of the non-standard apple implementation of usb charging....which probably explains why other gadgets such as my Garmin GPS and Palm Treo are aggravatingly finicky about their usb power supply..

Also appreciate your browndoggadgets.com site, as a source for small quantities of solar project related parts, that (I assume) have already been experimented with, as to their appropriateness for project/experiments (might suggest putting the wattage on the LEDs though).

One question I had: what would be a good source for the little tabs that one could solder on to NiMH AAA/AA batteries when replacing same in such items as Norelco rechargeable shavers and such? I have found sources for the Heat Wrap (like All-Battery.com) to bind multi-AAA/AA packs and such, but not the metal tabs (which would seem to be more stable/useful than a bit of wire, esp. when putting the battery pack back on the circuit board)..

Thanks again for the great instructable... bet you are one of the favorite teachers at your school..
Don't know if you still looking for this solution or not.

But you can buy "battery bars" at just about any hobby shop. They come in various sizes, just bring in the cells you want to connect to get the size you need. I have some rather small lightweight copper bars. Bars used in multi cell RC buggy racing (If the jump to LiPo has not been made) are longer and at least an eighth inch thick.
So i purchased everything from Radio Shack execpt the usb port(ripped one from a car charger). Wired all together last night but didn't glue in tin yet. Wanted to test it today first. Noticed this a.m. that my positive wire from battery box came off so I just twisted them together and placed it in the sun. Went to check a few hours later and plugged device in but it wouldn't charge. The only way I can get it to charge it to untwist that wire then the solar panel will charge device if in sunlight but if i hook that wire up it stops....need help.
amblowe8 months ago
Wish you had been my science teacher back in the day!
Schmidty1610 months ago
I want one of these but I want it to have a usb and be able to charge my iPod or anything else I had lying around and I still want it to be solar powered I also want to get everything at RadioShack if u get back to me soon that would be greatly appreciated.
if I cant find something like this I guess I will go to a minty boost and see if I can get everything at RadioShack.
spek1411 months ago
could i replace the charging circuit for a female usb port instead. what would happen
SpinedWave1 year ago
Can i use a another Blocking Diode instead of the 1N914 Blocking Diode? Because they hardly to get in me country. Thank You.
gpmelendez1 year ago
I'm mostly worried about the temperature that can be reached while charging under the sun. The eneloop datasheet ( http://bit.ly/YfvnqN ) says I can fast charge them up to 40 C. It doesn't say anything about trickle charging. What do you think?
OzzyManson1 year ago
i found a cable that looks like the one pictured, but was wondering if i still need to find something else? i don't think the bit with the capacitors on it is actually a part of the usb. sorry if this is a dumb question, im a DIY noob :3
Do you have to have the blocking diode?
Could I modify this with two pairs of AAs in a series-parallel arrangement? (one pair in parallel with the other pair, for double the capacity still at ~3V) Would I need a stronger solar cell, or would this one work fine?
DoctorDv1 year ago
What is the difference between this charger and your other solar USB charger?
-Doctordv
JoshuaZimmerman (author)  DoctorDv1 year ago
This has an iPhone cable, so you'd only be able to charge up iPhones or other apple gear.

USB chargers have a USB port, they are generic and work with everything.
Quick question, how come you can charge multiple types of phones with your solar USB charger, but you are unable to use one phones wall charger with another phone? Thanks!
-Doctordv
JoshuaZimmerman (author)  DoctorDv1 year ago
You probably can. Usually it's due to the type of "plug" that goes into the phone from the charger. Each company has a different shaped plugin (unless they're nice and use a generic mini USB port), which requires you to buy stuff from only that company.

Joshua
rcisneros2 years ago
I hate to tell you, but I've tested dozens of batteries brands. Literally. And almost none of them come close to their rated mAh.

Most no name recharagables are 50% at most.

Second tier, what I call name brand generics like Tenergy, yield around 75%+. (They have several lines and I have NOT tested the ones pictured.) Problem with these types is that the ones that test higher tend to drain faster that higher quality batts.

Name brands tend to be in the 90-99%+ range. Rayovac, Energizer, Duracell, etc.

The kings are the Sanyo and Sony Cycle batteries. They test at 100% and the the results are exactly the same for each battery.

-Bottom line is there is NO such thing as a 3000mAh battery as far as I know.
-Bottom line is there is NO such thing as a 3000mAh battery as far as I know.

Yeah, but there are 2850 mAh batteries like the ones in the pics.
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Yeah you missed the point. I can post pictures of batts that are labeled 3000mAh. That doesn't make them 3000. If you had a decent tester you could check it yourself.
If you tested the ones in the pictures, I really doubt you'd get near that number. Good luck with it though.
What the author meant was that with two batteries he can get 3000, not one has 3000, and with two sets he could get 4000-5000.
Actually, they're in a series to increase voltage. Two of them together is 2.4-2.5V with 3,000mA.

I switched battery suppliers awhile back because their batteries just plain sucked. I now use much better batteries.

If you really want a long and steady charge, switch to Lithium. $15 will get you a charge controller circuit board and a decent lithium battery. Then add on a diode and a solar cell and you're golden.
RelientOwl1 year ago
Do you have any idea of how to identify a solar panels Volts and Amps?
inquilab1 year ago
Hi Joshua- How would i go about building this device but for 3x 4x or 6x AAA batteries instead of 2x AA batteries? Appreciate your help.
Okay, so I'm a newbie, but wondering if all i'd need to do is buy this device:

http://www.aliexpress.com/product-fm/536521891-free-shipping-emergency-charger-AAA-battery-external-backup-battery-charger-for-iPhone-4S-4-3G-3GS-wholesalers.html

and then connect a 3.6 volt solar panel directly to the leads on battery case within this device (with a diode on the + side)

Would that work- charging my three AAA batteries from solar panel, while simultaneously also using these AAA batteries to provide a charge to my Iphone?
JoshuaZimmerman (author)  inquilab1 year ago
I really have no idea without taking on apart and seeing how it works.

It looks like it uses a boosting circuit of some kind, as 3 AAA rechargeables does not equal 5V, and a Li-ion would only be 3.7V.

Now you could, in theory, hook up a solar panel to it if it is just a boost circuit. However, you'd want to use something far larger than a 3.6V solar cell as a 3.6V solar cell will NEVER give you 3.6V. You'd want something larger than 5V with at least 200mA of current available.

Plus having batteries is a really good idea. Solar is not consistent, and batteries or a big capacitor helps regulate the flow of power.

Man, now I'm going to have to find one of these and take it apart!
Will the circuit boost enough to charge an iPad? I read my adapter and it says 10 watts.
JoshuaZimmerman (author)  blinkyblinky1 year ago
You know, the older iPads seem to work just fine, I've gotten reports that the newest iPads have issues. As I don't have a new iPad, nor do I know anyone who does, I have no way of testing.
I thought you needed 5 volts to charge an "i device". will it work the same with 2.4 volts or will it be slower?
JoshuaZimmerman (author)  NanoRobotGeek2 years ago
The circuit boost the voltage up to 5. Thus why we can use 2 AAs.
Oh... right. thanks i get it now
xxhydrax2 years ago
SOMEONE PLEASE HELP ME WITH THIS:

Ok, first let me start off by saying I am very very new to electronics and have absolutely no idea what some of these components. None the less, I still want to build this thing. Now I have 2 AA rechargeable batteries, the blocking diode (which I don't know how to install) and pretty much everything else on the list, EXCEPT 1 THING; the charging circuit. Since I said before I have no experience, I was wondering how I can get/make this circuit. Is their a detailed instruction on exactly how to do this? PLEASE help me.
wchiong2 years ago
As what you say we can't get a iPhone to charge directly from the sun , then why do we put in a solar cell ?
Because the solar cell charges the batteries, which then charges the iPod or iPhone
okay understood ! But how long will the it charge from 0% to 100% ?
nireves12 years ago

Hi Joshua
Thank you for this nice instructable!
its awesome
i was wondering if there is a limit to the voltage of the solar panel used?
could i for example use a 9volt 109mA solar panel?
and what kind of solar panel do you think would charge the AA's the fastest with the least amount of light without adding extra parts (except perhaps a diode or voltage regulator) to the circuit?
Thank you very much!
Sev
Amsterdam/Berlin
iApple guy2 years ago
I was reading the comments to see if anyone has already posted this question and it seems that you get cheap Chinese chargers. Do you know where I can get these for a very low price. I do not care if it is in store or online, all I want to know is where I can get a charger circut. A schematic is acceptable as well too make a charger.
kerec62 years ago
I have a question. A little while ago I bought this as a kit and made it. I charged the batteries and of course, I get the error message. I tried it with standard AA's, and got the same message. The thing is, it still charges, but very slowly. This happens with my friend's iPad when you plug it in to his old computer and it still charges. Is this normal??
JoshuaZimmerman (author)  kerec62 years ago
Charge the batteries up first, if you have a 3GS they're insanely picky.
I did charge the batteries- they've been in the sun for about a week now. I'm using an iPhone 4. And like I said, it still charges but it displays the error message.
Oppidum2 years ago
Mhn..and if I want to charge an iPad? what kind of cell should I use?
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