Solar Powered Cell Phone Charger

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Introduction: Solar Powered Cell Phone Charger

About: I know I can change the world--one person at a time--with one random act of kindness at a time. Affecting the outcome of someone's day positively is one of the greatest accomplishments, and it's contagious.

Power you cell phone via the sun.

Step 1: Materials/Tools

You don't need much to get this project up and running. I actually bought everything I needed at Radio Shack, and will provide the SKUs for each item in case you want to do the same.

Solar Cell (I used a 6v 50mA one)
SKU: 277-1205
Project Box (I used a 5x2.5x2 and it fits perfectly but any small enclosed box that you can cut holes into will do fine)
SKU: 270-1803
12VDC Car Power Outlet Socket
SKU: 270-1556
Vecro (or your adhesive of choice)
SKU: 64-2345

You will also need a soldering iron (15 watt. SKU: 64-2051B), solder (62/36/2. SKU: 64-013), and something to cut 2 holes in the project box (I didn't have anything available designed specifically to cut holes, but I just used my CRKT knife and it worked fine)

Step 2: Cutting Holes

Remove the top of the project box. There are already 4 holes for the screws it comes with. Holding the top horizontally, cut a hole at either the left or right end in between the current holes. This will be used to put the solar cell's wires into the box.

The next hole will be cut in the bottom part of the project box. Standing the project box up vertically, the hole will be cut in the small square side that is facing up in the air. The hole needs to be big enough to have the 12VDC socket fit in, but small enough to keep it snug. Basically start small and keep testing to see if the socket fits. You can always make the hole bigger, but can't make it smaller...as easy.

Step 3: Assembly Before Soldering

Take your solar cell and pull the wires through the top of the project box. This should leave the solar cell resting on the top of it. Next take the 12VDC socket and pull the wires through the hole that you just made in the bottom of the project box and firmly push the socket into place.

Step 4: Time to Solder

With the wires through each hole, solder the red wire of the solar cell to the red wire of the 12VDC socket, and the black wire to the black wire.

Step 5:

Once this is done, place all the wires into the box and place the top on. Velcro the solar cell to the top of the box. And lastly screw the top of the box down.

I had to wait 2 days before the sun came out, but it was worth the wait. It charged my phone right up!

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105 Discussions

please send this project with detailed explaination to my mail id - helen.merary@gmail.com

Great device! I'm curious about the input voltage from the solar panel - did you have to match it to the car charger or the phone?

6 replies

I would guess that the car charger device would regulate the voltage for him.

Incorrect. The car port is just that. A port. All it does is allow power to flow through it to the charging device. It, itself is not electronic in any way, except having power flow through it.

Example:
If you have twenty-four instead of twelve watts run to it, it will output at twenty-four, not twelve.

Incorrect. The car charger itself has voltage regulation circuitry in it.

I realize I've a tad bit late here, but I meant that the car plug does not regulate voltage; the charging device plugged into it does.

However, looking back on this, I'm pretty sure that this would be a near useless device as 50mA isn't going to be enough power for any modern device to even keep its screen going.

kenshi, there still needs to be enough power for the charger to knock it down to the correct level

knuxz the PORT is just a contact, as you stated. there is nothing else there.

lloydrmc, you are right in the charger, but technically Knuxz is also right, as he specified the PORT, not the CHARGER. the charger would be expecting 12V at like 10 Watts (i am not sure on the wattage, if i am wrong, i appologize) the charger probably has a transformer in it set to about 2.4:1, so if 6 volts go in, you will not have the 5V the phone is expecting, or what every the phone wants. i am going off current phones which normally go straight from USB at 5V.

Hello! I recently attempted your project but ran into a problem :-/ I have a droid x I am trying to charge and when I plugged it in, the battery kept draining. I figured the panel in your instructions was not enough to charge it so I upgraded to a 6v 1w 236mA panel from radioshack and it still drains even though it says charging. Also, in direct, full, sunlight the battery icon goes red with a "!" with the upgraded panel. I am at a total loss at this point and any info would be appreciated. Thanks for the awesome project! Lots of fun to scavenge and build lol!

1 reply

You can purchase a Diode to place in to the wiring. It will stop power from going in the reverse direction if the solar panel does not have enough amps/voltage. The local radio shack should have what you need for under $2.

Searching the internet on how to use the diode should give you plenty of examples.


Shon

how about adding a battery and charge that so u can leave it to charge in the sun and when you come home you can charger you fone =)

7 replies

You don't need a voltage regulator if you're using a car charger. The car charger takes care of that.

iPhones can be tricky, as they require voltages on other USB pins to be convinced to charge (which is accomplished by resistors between the 5V lines and the other pins). Look for the instructables on minty boosts (there are a number of versions), as they have info on how to make this kind of thing work with an iPhone.

if you use a 12V car to USB thing, and plug the Apple USB cable into the USB Port, then the cable handles the resistors, and all you need to do is make sure that you have 5V at about 2.1 A ( if i remember right) for optimal charge on the iPhone.

you could find a way to hook it up to a spare phone battery that way you charge your extra battery in the sun while you use the other one, and then when you need more power, just put the full battery in your phone and start charging the dead one.

I would be VERY careful about hooking any sort of solar cell to any kind of lithium (e.b. LiON) battery, which is what most cell phones have nowadays. Overcharging a lithium battery can result in a rather spectacular fire and/or explosion. Check YouTube for video of what this looks like.

with the system he designed, he could connect anything under 6v to it. as currently configured, he has to have it as a car style plug... if he spliced in another power port, say to screw terminals, or aligator clips, he could direct charge just about anything, and maybe use the terminals for a battery, with diodes so the panel could charge the battery, and the battery could power the port. WARNING! WARNING! WITH OUT VOLTAGE REGULATOR ON BATTERY RISK OF FIRE, EXPLOSION, DEATH! Some capacitors in a bank with some resistors and diodes may work better, and through a friends, ahem... experimentation... ahem... in electronics class... caps don't appear to suffer from overcharge problems... he plugged some 2000 mA caps into breadboard power supply at much greater than recommended voltage/amperage, and they did not suffer problems after multiple charge/discharge cycles. i know small caps can power small circuits depending on drain for at least a few seconds. So with the right circuit, and the right cap(s) you could build this with a decent "charge" capacity. and ultracaps would be even better, but have not seen any other than online.