How to Make a Cheap Solar Usb Charger




About: I just like making things and stuff

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)

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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

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


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    42 Discussions


    3 years ago

    Can the smaller round ones be use and how do I know how many I will need?

    since you post about 3 years ago I doubt i will get a reply but, my son is doing a solar power project and wants change something into a solar powered remote. Will using the panel from a garden light work directly? I'm not sure how to set any of this up

    3 replies

    Reply 4 years ago

    Actually a ps3 remote. They house a rechargable 1800 mah battery. We bought a 5v solar panel that if we can somehow create a way to mount it and plug into a mini usb we could hand it in a window to charge. Directly. He has to make an invention and although it wouldn't be overly practical, for his 3rd grade science fair, it would be a great way to show how to use solar power In a way a child would understand. I just want to make sure we don't blow up any hands or remotes in the process.

    it should work. the chaarge will be slow ut I see no reason why it would not work. I would recomend checking the voltage output of the panel just to make sure its around 5V or you could potentionaly damage the remote.

    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?

    1 reply

    Reply 5 years ago on Introduction

    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.


    6 years ago on Introduction

    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


    Reply 6 years ago on Introduction

    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


    6 years ago on Introduction

    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.


    6 years 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).

    4 replies

    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

    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.