Recycled, multi-voltage solar panel

If you have a bunch of old solar garden lights that don't work so well anymore, and you're thinking about pulling the solar panels off and making something cool with them (since, even if the lights themselves are dying, the panels probably still work), this instructable is for you!  This array combines versatility with efficiency; it can produce several different voltages, but without using a power-wasting voltage regulator or boost circuit.  It can be made with a few simple parts, tools, and minimal electrical knowledge.  The wiring is kind of complicated, so I'll endeavor to explain it as best I can.  Post a comment if you have any questions.

Step 1 Materials and tools

Solar cells; I used nine panels from the tops of solar garden lights; note that I mean only the panels themselves, not the batteries, charging circuits and lamps.  Save these for some other awesome project.
Wire; lots of it.  I used wire salvaged from two broken strands of incandescent christmas lights.
DIP switches; if you don't know what these are, they're little banks of two-terminal switches, usually used for programming microchips.  You'll need about 28 switches for 9 panels, or three banks.  Two should be ten-switch banks, one can be an 8-switch bank.  You can buy them from many electronics stores for a few bucks, and I guess you could just use a whole bunch of individual two-terminal switches if you can't find any.  These are just more convenient.
Wire clamps; the most versatile power output system.  You'll need two; red and black makes things easy.
A surface to mount the panels on; I used cardboard.  You could use almost anything.
Soldering gun; you'll probably need this to make wiring connections.  If you don't have one, good ones can be had for not very much money, and soldering will make your life easier.  Trust me.

Comments

[HarveyH44]

Wow, that's a lot of work. A little skeptical about if it was worth all that effort and added expense. The thing with solar panels, is that the output varies widely throughout the day. They are great for charging batteries, since they are usually very forgiving of spikes and interruptions. Some electronics don't like that too much, so directly driving them from solar panels isn't ideal for them. Voltage regulators to consume a whole lot of power, it's the excess that is wasted in linear regulators, and you need 2 to 3 volts over your target voltage, so it has something to work with.

[Deutschmann]

It was worth the effort; if you salvage the wire, it doesn't cost more than 10 U.S. dollars, tops. The power output actually doesn't vary as much as you'd think, if you keep the panels pointed at the sun. You are right that certain electronics wouldn't do well if connected to a system like this; Iphones spring to mind. But many devices will run just fine off of this; the output of the panel is only severely effected at the beginning and end of the day. This system wastes minimal power, since the power can be adjusted without regulators; I admit it sounds overcomplicated, but it could be made in a couple of hours, and it is capable of powering a wider range of devices than anything else I've been able to find or build.