Instructables

Simple Solar Powered USB Charger and Speakers

Before making this, I figured out what people (9+ years) use a lot nowadays and I came up with: cell phones and mp3 players.
A lot of people waste energy using these two items by buying the speaker systems for their mp3 players and charger their phones. Both uses usually end up with leaving the charger or system plugged into the wall, which is a big big waste of electricity.

So I developed a simple, green and cheap solution that everyone can do. This whole instructable can be made with recycled materials around the house, as long as you keep broken stuff like I do. If you don't that's totally okay, but you will have to order/go out to buy a few things.

Depending on your experience, it should take about 1.5hours for full assembly.

*Please read*
The black charger below is one that I made for me. I like the color black and I designed it based on what I like. I think that it's better to design something that you like and that you can put in you're own creative input into. So, I'm going to show you the basics on how to build one and I'm going to leave it up to you on how it looks. Have fun with it.
By following this instructable step by step you will have charger that looks like the white one pictured below
 
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i love the project!! i really want to create one.. can i have the circuit diagram for that project? i really really love the concept..
inotnrml3 years ago
the best wire strippers I've used is a good pair of finger nail clippers. In my tool box i have snap on pair a craftsman and a generic set of wire strippers but for small electronic/electrical wires finger nail clippers work the best
each of my solar panels has 3 wires due to a light sensor on top, how do I know which two are the electrical wires?
 Multimeter.
Rali9294 years ago
The problem with this design is that it is not compatible at all. If you think about it you are charging the battery, not running the phone or iPod of the solar panels. The only thing you would be able to charge is a larger model iPod like the 5G video or the Classic. Phone-wise the battery on a usual phone is only about 3.7 volts to 4 volts. when you are sending in 5 volts into the battery you are running the high risk of damaging your battery. A solution to fix this is to get rid of the voltage regultor and put in a potentiometer with a volt meter in order to get a safe voltage for the device. Also have the amperage at around 400-800 ma. This may charge a bit slower but it keeps your device safe.

*** Speakers are a smart idea but you need to have better speakers other than headphone speakers and have an amplifier to increase the volume.
I believe the point of the batteries would be in case the voltage from the Solar panels drops below around 6V. In this case without the batteries the volt regulator would stop working properly, however with the batteries the volt regulator can still work, and hence the iPod can still be charged. Also you can buy USB phone chargers which makes your voltage point a moot one, as if they run off the standard power supplied by a computer's USB (5V) then they clearly change the voltage supply before allowing it into the battery, otherwise there would be a lot more angry people out there!
But computers will adjust accordingly to the voltage
 False, it sends 5v, batteries need more voltage than they put out to charge, also the charging circuits are designed to take (usually) a decent amount over what is rated as a "just in case". If the phone charges from a usb port, it can take up to at least 5.5 volts no problem, the phone regulates the incoming current, the computer can't control the outgoing volts (it can't even keep it's own voltages in its rated range, so thusly 5 volts goes from 4.5-5.5volts without problems).
Eirinn Rali9294 years ago
a USB port from a computer delivers 5volts and a maximum of 500ma. The iPod nano charges directly from a usb port to the device so i assume it uses 5volts and a max of 500ma :)
Rali929 Eirinn4 years ago
i was not commenting about the charging capacity of the iPod but of cellular phones.
erosser Rali9294 years ago
I've been researching building something like this. Most iPod models have 3.7 volt batteries, rated from 300 mA/h (for the nano) to 800 mA/h (for the Touch). Ironically enough, cell phone batteries, or at least my very basic Motorola model, are also 3.7 volts! I imagine most iPod chargers tone down the 12V from the outlet to the voltage required, probably via a regulator, but I have never personally dissected one. After looking at this I-ble and many similar devices, however, my advice is don't worry too much about getting the exact voltage rating, since Solar panels tend to pump out a little less than they are rated for. If it were any more efficient, the world and its atmosphere would be a cleaner place... This is all speaking as an EE n00b, so please please correct me if I'm wrong! I like Rali929's comment about adding a pot. instead of a regulator, Much more versatile! Happy wiring!
Rali929 erosser4 years ago
Well thanks, but I have actually bought some solar cells from Radio Shack that actually go beyond what they are rated. I have some solar cells that should be producing 1.5v at around 300 mah but produce 1.8 -1.9v at 450 mah.
erosser Rali9294 years ago
Crazy! Woot for efficiency! I should look into those when I make my device. Thanks!
Rali929 erosser4 years ago
But thats in full direct sun... plus I live in California, so I guess it will adjust accordingly.
Rali929 Eirinn4 years ago
or... you could look on the back of the nano or on the web and find the battery rating.
killroy4 years ago
Do you know the voltage of the solar cells combined?
insane26424 years ago
Won't the audio quality be quite poor due to the fact that you are running a Stereo output, from the iPod, into a Single speaker? Also what power ratings are the speakers you've used in the black model?
Rali9294 years ago
Well it would probably be better to connect the batteries in parallel to the solar cells in order to charge the batteries faster. Usually those solar powered lanterns have low amperage and this would increase the amperage. Not much but some what... Overall you should probably use different solar cells if you amp this project up.
NightChaser4 years ago
I think you forgot to mention that the positive lead from the solar panels should connect to the negative lead from the batteries
zuner20124 years ago
Hey guys.. I was looking at a similar tutorial onlines. I found some great voltage regulators here: http://www.st.com/stonline/ . They give out free samples of the 5V 0.5 amp.. that's what you want
pshinoright4 years ago
and would'nt adding a heatsink to the regulator increase the amperage? what would that do to the charging efficiency?
Sylvanus4 years ago
Cool idea, very simple and clear instructions. I think I might make one, maybe add a small pocket amp too.
ldelmuro4 years ago
I want one! I am looking for the junk to build it now!
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