How To Make A Solar Powered USB Charger
Turn those so-so solar powered garden lamps into a useful, portable, USB device charger!
Step 1: Introduction
Solar powered garden lamps were a great idea that just haven't worked very well. Let me show you to turn these garden lamps into something really useful.
Step 2: Items
Prices for garden lamps are so cheap these days that I found this set of four on sale for ten dollars. But you can easily find them at garage sales or maybe even have some old ones lying around in the house.
The only other things you'll need are some wire and a female USB connector. I used an old floppy drive cable and a throwaway internal USB connector. Grab a throw-away baseball card sleeve and you're all set to make your own solar powered USB charger and power supply that works incredibly well.
Step 3: Take Apart The Unit
Taking apart the units is relatively easy, but in this case I had to do a little extra work to get to the solar cell. Normally they'll pop right out, but occasionally you'll find some attached with a weak adhesive. The cells are coated in plastic and our very durable.
Step 4: Voltage
Testing with a voltmeter shows an output of two and a quarter to two and a half volts. We'll wire two together to give us a four and a half to five volt output and then wire another set of two in parallel to give us the necessary amperage. If you don't understand what all this means, don't worry about it. Just follow the instructions.
Step 5: Floppy Drive Cable
I like the idea of using a floppy drive cable because the wires are designed to be flexible. Peel two off and separate the ends. Make several sets of these wires.
This is how you'll want to solder together your four units: positive to positive, negative to negative, a bridge on one set from negative to positive, another bridge, which we'll add later, a black wire to the negative post, and a red wire to the positive post. This configuration illuminated with a forty watt bulb will show us our target voltage of between four and a half and five volts.
Step 6: USB Connector
Next I removed the USB connector from the plate and then snipped off the two extra wires, leaving us with a positive and negative wire and the USB cable.
I then soldered these wires to the black and red wire of the solar unit. A plastic sportscard sleeve is ideal for holding the solar cells firmly in place, but I needed to cut a couple of flaps in two of the pockets in order to accomodate the wiring.
I slid the first two cells into the lower pockets and then slid the second two cells under the flaps. Then I secured each of the flaps using clear tape. Next, I trimmed off the excess plastic. This gave me a very flexible unit that could easily be folded into a shirt pocket, a backpack, or a glove box of a car.
The final step was to cut away small sections of plastic and solder the final bridge into place, and use some colored electrical tape to make it look nice.
Step 7: Testing
The final test was to take it outside. Here's my cell phone. The battery's completely dead. It shuts off by itself. I plugged it into the solar array and after a few seconds, the charge light came on. Not only was there enough power to charge it, I actually had enough power to turn the phone on and use it.
So now I have a portable, powerful, flexible solar power unit. I can use just about anything that requires a USB port for charging.