Introduction: Solar USB Phone Charger With Battery Backup

In this instructable I will show you how to make a solar powered USB charger for your phone or mp3 player. This is item is great because it doesn't always have to be sunny for you to charge you phone or other USB device. The way the circuit is designed lets the solar panel be constantly charging the batteries and by flipping the switch the batteries start to charge your USB powered device.

Hope you like it.

Step 1: Supplies

To make the Solar USB Phone Charger with Battery Backup you will need:

6 volt Solar Panel
4 AA Battery holder
4 AA  Rechargeable Batteries
2 diodes (I used 1n4007 but any will work)
Female USB 
Solder and soldering iron (optional)
2 100 Ohm resistors (only for apple devices)
Heat Shrink (optional)

You can find all of these parts at your local Radio shack.  Lets start making it.

Step 2: Making It

To make it just follow the circuit diagram as shown. Make sure all of your wires have good electrical connection. If you don't have a soldering iron than you can twist the wires together and cover it with tape. The first circuit shown charges all USB devices except apple devices. To charge all devices including apple products add 2 100 ohm resistors connected to the two data pins on the female USB as shown in the second picture.

If you have any questions then post it in the comments.


mehmood925 made it!(author)2016-11-08

what is the output voltage and current?

Zach+the+tech+guru made it!(author)2016-09-12

very simple ill think i make this because for what ever reaason my battery on my tablet dies really quickly.

ChandanZ made it!(author)2015-08-08

Super cool project, super cool.

CjB2 made it!(author)2015-07-13

So, my female usb, I'm pretty sure it has only 2 data pins. There would be no point in putting the resistors in parallel with a wire because the wire would just short them out. Is there a way to modify the circuit to make it work with the usb I have. I could be over looking the other data points so here's a link to the exact usb I have. Thanks

SuthentT made it!(author)2015-07-06

chrisbpr made it!(author)2015-05-13

What about using a spare usb car charger ,that way you get voltage regulation and a charge led for a few pounds at the most.

varun99 made it!(author)2014-11-05

can it charge ipads/iphones by changing the usb port

dgatchalian made it!(author)2014-03-01

HI. :-) I Made my own schematic with 5v voltage regulator to get 5v voltage output.

fhopkins1 made it!(author)2014-06-29

now can you add 3 things?

2 leds one after the swch and one after the solar panel

and a usb in for charghing

bootch made it!(author)2014-04-28

Having trouble with continuing the charge. Occasionally get a device not supported message. Reason why?

Lars223 made it!(author)2013-06-28

You wrote that you need a 4AA Batteryholder but I only see a 2AA one. Which one do I need?

mshbi made it!(author)2013-06-28

Its is a 4AA battery holder. In the picture there are two more AA batteries under it

etirado made it!(author)2014-04-27

how can I prevent overcharge I basically want to know when the batteries are full so I can shut it off or a piece of logic to keep it from overcharging them

geotheos made it!(author)2014-03-09

What end of the resistors do you attach to the female USB

Charly_ZA made it!(author)2014-02-26

Hi. Thanks for the great tutorial. I'd appreciate it if you could help me with my take on this project.

gsteiner1 made it!(author)2014-02-22

This is Fantastic! Could you make a tutorial/video on how to make a pure solar charger (no battery's.) I think you could use a 4.5v 1w solar cell and instead of a female usb you could use a 3-5v to 5v voltage step-up/inverter.

minetorials79 made it!(author)2013-07-29

how long does it take to charge an iphone

xyndaen made it!(author)2013-07-02

simple but effective. anyway there may be some improvement. for example i advice germanyum diodes in this project cause of gaining the voltage when it is compared with silisium ones. the other thing i advice is using and capasitors zener diode 5v for the usb connector to stop voltage changes. 10nf is OK. 7805 is also good choice for this kind of circuits.

mshbi made it!(author)2013-07-02

Good ideas. Thanks

rmarc made it!(author)2013-06-30

Then how does the altoids container shut?

mshbi made it!(author)2013-07-01

Good question. I can't get it to shut all the way. I would recommend using a different container

jclaudiu made it!(author)2013-06-30

is this working? do u have a video on that?

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