The Nintendo DS Lite seems like it was made to have solar cells put on it. It has a large amount of surface area on the top and bottom that both face upward when the DS is opened. The top and bottom faces each have exactly the right amount of room for two 60x60mm solar cells side by side (four total). Each one has a maximum power output of 3 volts at 40 ma. The top two are connected in series and so are the bottom two. These two sets are wired in parallel to get a total of 6 volts at 80 ma, perfect for trickle-charging the battery.

My original instructable had a couple of flaws, some of them very important. I was originally going to post the updates on my first instructable, but there were so many changes that I had to make a whole new one.

Among these changes are:

Overcharge protection (the main reason I wrote a new Instructable)
Only one wire connecting the top to the bottom, not two little annoying ones
No wires around the edges
No annoying diodes where your hand goes
You can get the stylus out now (I accidentally put a solar cell over it the first time, silly me)

Another thing I need to mention is why I didn't use a 5v regulator and hook it up to the charging jack of the DS. The reason I did not do that is because I would have to rewire the solar cells to produce a higher voltage for the voltage regulator. This would give me less than 40 ma. Running that through a voltage regulator reduces that even further. Also, the DS would have its charging LED on if I did this. That would suck about half of the remaining current, leaving next to nothing for the battery. If I did it that way, the battery would charge about 4 times slower.

This is my third Instructable, and if you have any questions, don't hesitate to post a comment! Don't forget to rate and vote either!

Step 1: Materials

The materials required for this instructable are:

Four (4) 60 x 60 mm solar cells http://www.allelectronics.com/make-a-store/item/SPL-61/SOLAR-CELL-60MM-X-60MM-X2MM/-/1.html
Two (2) diodes, almost any kind should work http://www.allelectronics.com/make-a-store/item/1N4001/RECT-DIODE-1AMP/50PIV/-/1.html
One (1) Overcharge protection chip http://www.batteryjunction.com/prcimopfor3l.html
Some thin wire (preferably at least two colors)
Scotch tape
Electrical tape
4.2 cm long piece of thin heat-shrink tubing
Some ribbon
Nintendo DS lite (really?)

Tools:

Hot glue gun with glue
Soldering iron with solder
Wire cutter/stripper
Multimeter
Helping hands tool (not required, but helpful)
Solder Sucker (helpful if you mess up)
Sandpaper
Small phillips screwdriver

Step 2: Make the Panels

This is probably the only step that is the same as the old instructable. Take two of the solar cells and solder the positive end of one to the negative end of the other. You can tell which is which because the negative end came with a little black mark by it.

After you made one panel, use the other two cells to make another.

Step 3: Wiring Part 1

Pick one of the panels you just made, this will be the top panel. Cut a length of wire a little over 10 cm long and strip the ends. Solder one of the ends to the positive (no black line) end of the panel. Run it to the middle of the panel, tape it, and bend it straight down. Do the same thing to the negative end with a wire about 20 cm long.

Step 4: The Top Diode

Take one of the diodes and glue it at the bottom of the panel, right between the two cells. Solder the anode, or positive side of the diode (the one without the white line) to the wire coming off of the positive side of the panel (the short wire). You may need to cut off some wire if it is too long. Cut off any excess wire from the diode when you are done.

Step 5: Wiring Part 2

Solder one end of a wire that is at least 10 cm long and solder one end to the negative end of the diode (the one with the white stripe). Bend it to the right, along with the other wire from the panel. Tape it in the middle of the right cell and bend them down. Put some tape over the diode, also. This helps hold it in place.

Step 6: Heat-Shrink Tubing

Take your 4.2 cm long piece of heat-shrink tubing and slide it over the two wires. Rub it with your soldering iron to make it shrink to a tight fit around the wires.

Step 7: Join the Panels

Take the other panel and set it under the one you were just working on. Overlap the heat shrink tubing onto the bottom panel (just a couple of millimeters) and glue (or tape) it.

Step 8: Add the Overcharge Protection

Take your overcharge protection chip and glue the bottom to the bottom panel as shown in the picture (it doesn't take much glue). Solder the positive wire from the top panel to the P+ terminal on the chip. Solder the negative wire from the top panel to the P- terminal on the chip. If you don't know which wire is which, use a multimeter. Tape the wires down to the panel.

Step 9: Bottom Panel Negative

Cut a short wire and strip both ends of it. Solder one end of it to the negative end of the bottom panel. Solder the other end to P- on the chip. Tape down the middle of the wire.

Step 10: Bottom Panel Positive

Cut another short wire and strip both ends. Solder one end to the positive end of the bottom panel. Solder the other end to the anode of a diode (the anode is the end without the white line). Glue the diode to the bottom panel in the place shown in the picture, then put some tape over it. Cut one more short wire and strip both ends. Solder one end to the cathode of the diode (the cathode is the end with the white line) and the other end to P+ on the chip.

Hooray! You completed the panel assembly!

Step 11: Prepare the Battery

Take the battery out of the DS by taking off the battery cover and prying prying the battery out. Cut two medium pieces of wire (a little over 10cm) and strip both ends. Use one color for both of them, you will need the other color for something else. Clamp the battery into one arm of the helping hands tool and one of the wires into the other. Position the wire so that it touches one of the battery terminals. Solder (you heard me right, solder) the wire to the battery.

You guys are going to kill me in the comments for soldering directly to the battery, I just know it. But there was no other obvious way to do it, and it had to be done.

Repeat this with the other wire and the other battery terminal. Cover the terminals with a piece of electrical tape. Test your wiring with a multimeter by connecting it to the wires from the battery. DO NOT LET SOLDER SHORT OUT THE TERMINALS OR ALLOW THE WIRE ENDS TO TOUCH, THE BATTERY COULD EXPLODE!!!!!!

Step 12: Prepare the DS

Cut and strip two medium lengths (a little over 10cm) of the other color wire. If you don't have another color, mark the ends of these two, you will need to tell them apart from the others.

In the slot where the battery was, you should see two terminals. Wedge one end of one of the wires into one of the terminals and use the helping hands tool to hold it in place. Solder the wire there using only a small amount of solder. Repeat this with the other wire and the other terminal.

Place a strip of ribbon into the battery cavity so that the ends come out of both sides. Because we added some stuff to the terminals of the battery and the DS, it is very cramped in there and the battery has to be forced in. The ribbon is very important and it is near impossible to get the battery out without it.

Step 13: Prepare the Battery Cover

Because we are trying to squeeze four wires through the battery cover, it is very important to sand a nice space into the side of the cover. This is pretty much a required step. I already cracked my battery cover from trying to force two wires through it in my previous Instructable, so with four this is a necessity.

Do this outside because it creates lots of tiny plastic particles that float in the air and probably isn't the best thing for your lungs.

After that is over, screw the battery cover back on the DS. The four wires should fit nicely through the groove you created. Put a piece of electrical tape over it to hold the wires in place. Put a piece of tape over one of the wires from the battery to keep it from shorting.

It is also a good Idea to turn on the DS at this point in time. If it doesn't turn on, you're doing good! If it does turn on, you probably forgot to cover the battery terminals. Do that now if you have'nt.

Step 14: Unite the Panels and DS Together!

Set the DS and the bottom panel right next to each other, and make sure the wires from the DS can reach the chip. Solder the positive DS wire (the blue one near the top of the battery compartment) to P+ on the chip. It should be the third wire being soldered to that terminal. Then take the negative wire from the DS (the blue one near the bottom of the battery compartment) and solder it to P- on the chip. It should be the third wire to be soldered to that terminal. Tape the wires down.

Take the positve battery wire (the red one near the top of the battery compartment) and solder it to B+ on the chip. It should be the only wire on that terminal. Now, before you solder the negative battery wire, test it with a multimeter to make sure there are no shorts. Set the multimeter to measure current, touch the positve terminal to B- on the chip, and touch the negative terminal to the negative battery wire. I got about .01 ma, because the DS uses a small amount of power in standby. Now do the same thing with the voltage setting, and you should get about 3 volts. This means that power is ready to flow through the DS. If either of your readings are way off, check your wiring. If you got them, proceed.

Take the negative battery wire and solder it to B- on the chip. It should be the only wire soldered to that terminal.

You are now ready to test it!

Step 15: Test the Setup

The title is pretty much self-explanatory, turn on the DS. If it turns on, CONGRADULATIONS! This means power is going through the chip and coming back into the DS. If it doesn't turn on, first check to see if the battery is charged. Then check all of your wiring with a multimeter for shorted or missing connections if it still doesn't work.

You can now proceed to attaching the panels to the DS.

Step 16: Attach the Panels

Now that you know that it works, it is time to attach the panels. First hold the DS on its side (see first picture) and arrange the bottom panel underneath it so that no wires poke out the side. Use tape to hold stubborn wires in place. Once it is arranged properly, put a dab of glue on two of the corners of one side (for example, the upper-left and lower-left corners). Quickly press that side of the panel onto the DS, making sure it is straight and isn't covering anything important (L and R buttons, stylus, etc.) and hold it until the glue has cooled. Then gently lift the other side a little bit, apply glue in the corners, and press it back down. Having glue in the corners instead of a big blob in the center makes the panels easier to take off if something doesn't work.

Once you have the bottom panel attached (see second picture), fold the top panel onto the top of the DS (see third picture). Use the same glueing method as with the bottom panel.

Tip: press hard while the glue is drying so the panels don't stick out as much.

NOW IT"S FINISHED!

Step 17: Option 2

In my previous instructable, many people were saying they wanted to build a base that would stay in the sun all day collecting power and transfer it to the DS overnight. So I came up with a schematic for a device like that.

This switch changes between charging the battery from the solar cells and transferring the charge to the DS.

Step 18: Enjoy Not Using the Charger!

Hooray, you finished!

Whenever I am not using the DS and it is sunny outside, I set the DS in the sun to charge. I never leave it outside, I just set it by a sunny window or on the floor. Unlike my previous instructable, it doesn't mattery how long you leave it in the sun because the chip protects the battery. The solar panels are made for charging the battery, so don't get the idea that you have to hold this in the sun to play it. Also, the way I did this still works with the charger,

Ever since I did this, my DS never needed to use the charger. It works excellently and looks cool too. It has a much sleeker design than my previous solar DS and the protection circuit saves the battery. Not only is this good for the environment, but you will never have to worry about bringing the DS charger with you again!

By the way, do not let the security people see this in an airport. You have been warned.

Here are some pictures of it charging. It is propped up on the stylus to get as much sun as possible.

Thanks for viewing, and don't forget to rate! I hope you try my project, please send me pictures if you do this! If you have a question, don't hesitate to ask, I will gladly answer it!