AKA: Solar powered walkway version 2

This is my second use of a distributed solar lighting system, where the panel can sit somewhere in the sun and send power to the lights that are in a shaded spot. I guess its kind of a half step between solar garden lights and wiring your home for solar power. The result in this case is a single panel mounted to a sunny spot on a wall that sends power to a string of glass bottles underneath a grape arbor.

At some point after I built my Solar Powered Walkway, my brother and his family came over for a visit. Everyone seemed quite impressed with the lights, especially his wife. Ted had just finished building a massively oversized grape arbor for the gigantic grapevine that's been cluttering up his backyard for the last several years, and Michelle asked if she could have a set of the lights to put under the arbor. I thought this was a great idea and told them that if they paid for the materials I'd be happy to build something for them.

Of course, since I'm never happy to just leave well enough alone I decided the original design could use some work. So, I started tweaking things, a little here, a little there, and soon enough the result was something quite different from my original design.

About halfway through building this I got to thinking about the fact that I never get my sister-in-law anything for birthdays and Christmas, as I'm never really sure what she'd like. I am awful at buying presents for people. However, here I'd been presented with something that I knew for certain she'd like, and her birthday was even coming up soon! I ended up finishing the build the week before her birthday, and presented it to her the weekend before her party so we'd have time to set it up in the arbor.

Step 1: Stuff You'll Need

Some of this stuff you can buy from online stores, but other parts you'll have to be creative to obtain.

Most importantly, you'll need a set of solar powered Christmas lights. I used a set from dealextreme.com and then altered it to make it work for my purposes. If you don't feel like making some major changes to the electronics, I'd recommend you find a different brand. These were not the best quality, the brightness of the LEDs was somewhat disappointing, the battery they came with didn't work, and the solar panel wasn't able to charge any battery enough to run the lights for more than a few hours. That being said, I was able to make it bigger, better, and stronger with some work and extra parts.

If you go with a different brand of Christmas lights you may or may not need the following items, but if you go with the dealextreme lights you definitely will:

A solar panel that puts out about 2v@600ma (I built one out of fractured panels from Electronics Goldmine)
A pair of decent rechargeable NiMH or NiCd AA's, 1.2v@2500ma each
Around 150-200' of light gauge speaker wire
A 2xAA (or two 1xAA) battery holder wired in parallel, not in series (I hacked up some old electronic gadget and rewired it for this)
Some sort of case to hold your new solar panel (I built mine out of . . . well, you'll see that in a future step)
Some cedar boards (I used a single cedar fence picket)

You definitely will need:

Epoxy
Silicone sealant
Paper towels
Stiff wire
Electrical tape
Nails/screws
Krylon clear matte spray
Clear glass bottles/jars/vases (get them second hand)

As to tools, you'll need the usual assortment of modern tinkerer's tools:

Dremel
Hot glue gun
Hammer
Screw driver
Wire cutters
Pliers
Soldering iron

Step 2: Prep the Bottles / Shameless Krylon Plug

A note on obtaining the bottles--I picked mine up from a local Goodwill, for $0.50 for the smallest ones up to $2.00 for a nice Patron bottle. Some of the jars had potpourri and glitter and such in them and had to be cleaned out, others were actually small vases. In all I ended up with 13 of them for less than ten bucks.

After you've cleaned them out, allow them to dry completely. I wanted to frost the glass like I do when I'm making sun jars, but I didn't want to use the same opaque frosting spray I've been using. I wanted something a bit more transparent for these lights, more fogged than frosted. I ended up settling on Krylon matte finish, which worked out great. Take each jar and lightly spray a bit of the matte finish into each bottle, then allow to dry.

Step 3: Install the Lights and Extend the Wires

Be warned, this is a fairly long and arduous step!

The reason a strand of solar powered Christmas lights works so well for this project is that it has a centralized driver that runs 60 individual lights. The big drawback of course is that you're going to have to extend the wires a bit unless you want all the bottles clustered in one spot.

With sixty lights to install in thirteen bottles, I couldn't just divide them up equally. What I ended up doing was putting four in each small bottle, five in each large one, and six in the big Patron bottle.

Before you begin putting the lights in the bottles, cut several lengths of speaker wire about three feet long. The measurement doesn't have to be precise as long as all of the strands are about the same length. Strip about 1/2" of insulation from each end.

Start at the end of the Christmas lights farthest away from the battery. Pick your first bottle and decide how many lights are going into it. In the middle of one of the wires between the last light going into your bottle and the next one in line that isn't going in, cut it in half and strip 1/2" of insulation from the wire. With the set of lights I was working on there were five wires between each light, which meant making sure to have at least that many lengths of speaker wire handy, one of which would have been separated into two separate wires.

Splice the wires Christmas light wire and the speaker wire at each end and solder them up. Cut another Christmas light wire and repeat, until you've done them all and that section of wire has been extended. Wrap each of the spliced sections in electrical tape, making sure none of the bare wires are touching.

Stuff the LEDs into the bottle. Take a strip from a paper towel, fold it up a few times and wrap it around the wires just above the electrical tape. You need just enough paper towel to create an interference fit between the paper towel and the neck of he bottle, holding the wires in place temporarily.

Once this is done, get another bottle ready and repeat.

Step 4: Seal in That LED Goodness

Next you'll want to keep out the constant rain that comes 9 months out of the year . . . what's that you say? It doesn't rain incessantly where you live? Preposterous! Even if that were true, you'd want to keep out the morning dew and the occasional drizzle, so that's what we'll do in this step.

Get a decent silicone sealant that's suitable for outdoors applications. Get all of your bottles set upright and make sure you've got 1/4 to 1/2 inch of room above each of the paper towel plugs. Squeeze in some sealant, making sure to get plenty in amongst the bundle of wires. Allow to dry overnight and vacate the area, uncured silicone is nasty stuff!

When it's all done you should have a strong but flexible silicone plug at the top of each bottle.

Step 5: Juice That Power Supply!

If you bought a higher quality set of solar Christmas lights, you can probably skip this step unless you really want to increase the capacity of the lights. I've not tested this yet, but I suspect the solar panel I used will be able to send enough power to the battery to light the bottles up for a while even on a gray and short day.

Testing the solar panel revealed that it was producing about 1.4 volts at around 100ma, which SHOULD be BARELY enough to charge the supplied 1.2v 1000ma battery. What I discovered was that the battery was a dud right out of the box, and even putting a functional battery in its place resulted in about an hour's worth of full power and two to three hours of steadily declining brightness.

Obviously this would not do.

My solution was to gut the whole thing, get a new and better solar panel and replace the single 1.2v 1000ma battery with a pair of parallel wired batteries that would work as a single 1.2v 5000ma battery. This is clearly overkill, but hey, it will definitely keep it's brightness for quite a while like this!

First you'll need to dismantle the solar panel and driver. Really, the only part we're keeping here is the circuit board.

Next up, find or build a better solar panel that can charge your new and improved battery pack. There are already instructables detailing both how to build a solar panel out of broken solar panels as well as how much power you'll need to charge a battery with the sun, so I won't duplicate them here. The general rule of thumb when determining how much juice you'll need is that you match of slightly exceed the voltage of the battery and get about 10-15% of the maximum amperage of the battery. I know that's not a super technical or precise explanation, but living by those guidelines I've never set a battery on fire or anything. The solar panel I made puts out about 2v at 600ma in full sunlight, more than enough to charge the batteries I used.

Speaking of batteries, I used two standard NiMH AA batteries for this project, wired in parallel. That means positive to positive and negative to negative, rather than in series (positive to negative) like you see in most electronics. The difference is that when you wire in series you add the batteries' voltages, but when you wire in parallel you add their amperage. Since I knew the circuit board was designed to operate at 1.2v, I figured I'd keep that and just increase the amount of power available to it by 5 times!

After you've got your parts, you'll need to build some sort of water resistant case with a clear panel to shove everything into. I used the paper catch tray from an old Epson CX5400 and a sheet of perspex from Home Depot, but you could use pretty much anything of the right size and shape!

Basically, I just installed everything as best I could and started hitting it with the epoxy and silicone. What I ended up with was a panel about 1 foot by 8 inches that had the solar panel in the middle, the circuit board on one side (with the control switch sticking through the back), and the batteries on the other. Check the pictures below and image notes for more details if you need them, but this is really just a step where you'll need to improvise.

After that was done, I built a little stand for it to be mounted to the top of the arbor, hopefully avoiding the grape leaves. I used cedar as I've heard about a million times that cedar is weather resistant.

After this is done, I recommend taking everything outside for a day and making darn sure it works before installing!

Step 6: Install and Enjoy

If you're in the northern hemisphere, find a good south facing spot for the solar panel near where you've decided to hang the arbor lights. My brother nailed the panel to the south wall of this kids' playhouse.

We actually started the install on the far end of the arbor and put the panel up last, but before we did anything we just lay it all out on the ground below. Once the lights were positioned roughly where Michelle wanted them, it was time to start hanging the lights. While Ted got up on the ladder and put a nail in the arbor, I would wrap about a foot of wire around the neck of the bottle. Then we hung each one, moving back towards the planned destination of the solar panel.

Once all the bottles were hung, the panel was nailed to the wall and we were done!

Step 7: Final Thoughts

Ah, another fun project come to an end! The night of Michelle's birthday party she totally bragged on me and the lights I built for her, and everyone seemed pretty impressed, so I really hope it makes up for all the presents I haven't bought her!

All in all, this one was a lot of work! I totally think it was worth it, but if I ever make something like this for someone else I will most definitely make sure to buy a better set of solar lights. These ones were just too much work.

I must truly apologize for the quality of the night time pictures! My cat, who I love but sometimes want to strangle, knocked my camera on the floor the night before I installed these. While the camera still works, the buttons that allow me to control light sensitivity and shutter speed are broken. It is currently impossible for me to take a decent long exposure at night so the full effect of the lights is lost somewhat. I will post some better ones once I get a new camera, but that probably won't be soon due to financial constraints. If anyone out there has some recommendations for a reasonably good quality but low priced camera with basic manual controls, I would really like to know about it!

As always, please take a moment to comment, rate, and/or subscribe! I really like hearing from people about their thought regarding my instructables. Also, if you build something based on or inspired by my project, post some pictures and I'll send you a digital patch! Oh, and I'm experimenting with boldfacing important points in my instructable. What do you think? Good idea or kind of stupid?