Picture of How to make a cheap solar usb charger
In this instructable I am going to show you how to make a solar usb charger from old garden lights 

With that charger you can charge every device that uses the usb port to charge like : (mp3 player, iphone,psp's etc.)

(In my solar charger i put some led's to be able to use it as a torch)
Remove these adsRemove these ads by Signing Up

Step 1: What you will neeed

1) two solar panels from garden lights
2) 4AA rechargable baterys
3) 4AA baterry holder
4) one female usb connector
5) a small button
6) a case
7) some wires
8) three 3.6v led's
9) two 1n5817 blocking diodes
10) one dpdy 6 pin push switch
11) one 150 ohm resistor

Step 2: Taking the solar garden lights apart

Open the solar light and take the solar panel out of the light

Inside there is a small circuit where you can take the two diodes and also some leds

(the battery that come with the light will be about 800mha. we don'd need that low capacity.The capacity that we need from each baterry has to be about 2000mha)

Step 3: Diagram

Picture of Diagram

Now you need to heat up your soldering iron and wire every thing as seen the diagram so be carefull and make sure that all the connections are covered with electrical tape

Step 4: Some photos


Could you possibly re-post the schematic with labels that will download in PDF format?

Could you please send me a copy of this design also? I'm trying to solder your charger here but my iphone 4 doesn't get charged. HAve to say I have soldered everything except the solarpanels. But my batteries are chaged so I guess the LEDs should at least work or the iphone should charge?
In order to charge an IPhone or apple device you actually need to use a different set-up as apple devises need more input than just a charge. The usb cable has 4 wires.. red & black for power and green and white for data. The IPhone and other apple devises use the green and white wires to confirm that the charger is compatible with it. so you will need a different circuit in order to charge your apple devises.
michaelb21 year ago
NiMH will show a higher voltage ( 1.3-4) The nominal voltage is close to NICd at 1.2.
Some solar lights use two cells so it is a good idea to put the solar cell on a voltage tester in bright light and use accordingly
Can I just wire it straight to the USB and forego the batteries?
Yes, see below:

aekara (author) in reply to ticouneJun 26, 2011. 7:30 AMReply
if you don't use the batterys the charge will be very slow and it has to be under the sun and if you use the batterys tha cahrge will be very very faster!!!!

remember that if you have big solar panels it may work :D
anetos1 year ago
Could you inform me how many voltage have the solar panels?
Thats because i dont have the same and i suppose that not all solar panels have the same voltage.

Thank in advance.
jjones1221 year ago
I'm doing the same thing with a store bought usb battery charger, solar panel and usb cable, Q? Where would the USB black and reds connect too?
Your system has a lot of flaws.

First, you're getting a max of 5V. 2.5 + 2.5. Thats a max potential of 5V. You're only going to get that during the summer, at noon, with a clear sky. The other 99% of the time you're going to be under 5V.

With solar you always want to over shoot for power. Big 12V charging systems have solar cells with a max output of 18-22V, so that even in poor conditions you're still getting the 12V you need.

The other problem is that you've got 4.8V of battery being charged by a max of 5V of solar. To charge up 4.8V of battery you're going to want at least 6V worth of power going to the batteries, otherwise you're going to be waiting for a very very long time for them to charge.

Lastly, USB is 5V. Your batteries only put out 4.8V. A lot of gadgets won't charge from it. In fact newer iPhones (3GS and 4) won't charge from this setup because they require special USB settings to work. Believe me, I've tried.

A better solution, one that uses less batteries, is to use a boosting circuit. This way you can use two batteries and boost them up to 5V. You can buy them off the internet for under $10. This way you could also use your 5V of solar to charge 2.4V of battery (2 AAs).
aekara (author)  JoshuaZimmerman3 years ago
yes i know that the solr panels need LOT of time to charge the batterys

and about the battery:each battery sais that puts out 1.2v but mines put aou 1.36 so 1.3*4=5.2volts and becouse my batterys are ratted 2000mha can charge up to 3 devices

and also if anyone wants to charge and iphone ipod etc. can put a 10k diode in the data+ and data- and trust me it works on my iphone 3g

10k diode??
100k ohm resistor for the iphone 4 and 4s
As batteries lose their charge their voltage drops. This means that you're not going to be able to get a full 2000 mah of charge out of the batteries because when they drop below 5V your iPhone will probably stop charging, or slow charging down quite a bit.

3 devices? That all depends on how big the batteries are in the 3 devices you're charging. I was under the impression that iPhones had batteries that were over 1000 mah, which means your charger would charge up one at best. That is if your voltage doesn't drop to an unusable level.

Also, while your iPhone may work fine NEWER iPhones, those being the 3GS and 4, will most certainly NOT work with this setup. A 10K resistor to the data ports may work for newer phones. May.
aekara (author)  JoshuaZimmerman3 years ago
well when i said 3 devices i mean that i charge 2 mp3 players and one mobile phone :)

and about the 10k resistor i tested the charger to a frient iphone 4 and belive me or not it works :P
Hey, I really like the USB thing, but Josh might have some great advice for improvement on it... I'm gonna be using some of your ideas with Josh's improvements and another guys waterproofing for my own project, thanks man.
Or, for a couple of bucks, you could build a joule thief circuit
oscaram123 years ago
Hi, thank you for your instructable, greetings from Mexico; I have a question Can I use another diode in the proyect? it´s difficult to me here find that model, I understand that I can use a standar rectyfing diode like the 1N4007, it would be less eficient I think, but you think that will work? Thank you for the answer.
aekara (author)  oscaram123 years ago
if you use that diode it will drop the votage about 0.8v and if you use the 1n5817 diode it will drop the votage for about 0.2v

but if you want try it with the 1n4007 diode and tell me if it works!
did the 1n4007 diode work cause the best i can find is a 1n4005 diode... do you think that will work? btw, im 15 so i dont know much about this.
Yes it will also work.
bluebox173 years ago
hi, will this work with a 1N4003TR rectifier diode?

linuxjunkie3 years ago
is there any type of regulator on this rig??
aekara (author)  linuxjunkie3 years ago
no there is no regulator at all
Hydra Head93 years ago
Does it work with 1n5817 rectifier diodes? Because I cant find any others
aekara (author)  Hydra Head93 years ago
yep it wil work
outdoor1013 years ago
is it okey if ill be using 4AAA batteries instead of 4AA?
aekara (author)  outdoor1013 years ago
yeah sure it is posible but make sure that the batterys are rechargable and have at least 1000mha of power
thnx alot. God bless.
ticoune3 years ago
What about not usging batteries?

aekara (author)  ticoune3 years ago
if you don't use the batterys the charge will be very slow and it has to be under the sun and if you use the batterys tha cahrge will be very very faster!!!!

remember that if you have big solar panels it may work :D
auresti3 years ago
what do the 10K resistors do? can you make a diagram because I want to charge a Samsung Captivate (1500 mah battery)
aekara (author)  auresti3 years ago
you connect the 10k resistor to the data lines on the usb connector (D+ D-) and it trick the device to make it charge
auresti aekara3 years ago
Oh...Do you have a diagram?
aekara (author)  auresti3 years ago
no i dont have but i will make one for you !