Picture of Solar Altoids iPhone/ iPod Charger

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I originally made my Altoids USB Charger to use with my iPhone, only to find that Apple being Apple doesn't let it's products play nice with generic USB chargers.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

Step 1: What You Need

Picture of What You Need

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

Altoids Tin

Soldering Iron
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?

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VidDroog4 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.
This is an awesome website. I hope that you are able to make big bucks off of it. PS I really like the usb kit design. It looks rustic but also helpful.
RelientOwl3 years ago
Do you have any idea of how to identify a solar panels Volts and Amps?

use a Volt/Ohm multimeter with Amps included usually cheap analog or slightly more for digital Most home building supply stores - even wal-mart.

JoshuaZimmerman (author)  RelientOwl6 months ago

Volt meter and amp meter.

Do you have to have the blocking diode?
JoshuaZimmerman (author)  schoonovermr6 months ago

Very much so.

SpinedWave2 years ago
Can i use a another Blocking Diode instead of the 1N914 Blocking Diode? Because they hardly to get in me country. Thank You.
JoshuaZimmerman (author)  SpinedWave6 months ago

Anything similar would work.

this is awesome! But what if I use a different lightning to usb cable for my apple devices? I prefer the longer ones something like this one ,

http://bit.ly/legitapplecable .

Do you think it will worked? You are awesome man. I think I'd rather do this one than buying a new one. Thanks I will keep you posted after I finished mine.

JoshuaZimmerman (author)  eureka.gomez.356 months ago

Use make up one with a standard USB port on it. It's much easier and then works with anything, including a lightning cable.

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.
amblowe2 years ago
Wish you had been my science teacher back in the day!
Schmidty162 years 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.
spek142 years ago
could i replace the charging circuit for a female usb port instead. what would happen
gpmelendez2 years 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?
OzzyManson2 years 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
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?
DoctorDv3 years ago
What is the difference between this charger and your other solar USB charger?
JoshuaZimmerman (author)  DoctorDv3 years 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!
JoshuaZimmerman (author)  DoctorDv3 years 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.

rcisneros4 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.
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.
inquilab3 years 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:


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)  inquilab3 years 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)  blinkyblinky3 years 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)  NanoRobotGeek3 years ago
The circuit boost the voltage up to 5. Thus why we can use 2 AAs.
Oh... right. thanks i get it now
xxhydrax3 years ago

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.
wchiong3 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
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