Low voltage landscaping lights are 12 volt - the same as a standard LED spool. So why not take advantage of this and create your own LED landscape lighting? The steps are simple, and the results can be amazing. It all comes down to how and where you mount the lights. Under stairs? Around a contoured surface? You can even use your existing landscape lighting transformer, or pick up a relatively low power one.
In the above photos, you'll see I have side lighting on our stairs, lighting under our railings, under stairs and even under a deck ledge overhanging our pond. I'll be using 12V white LED 5050 spools for these - a spool of approximately 14 feet averages $15 online. You can get cool or warm white. You could also use RGB full color, but I'm not covering that. My install / project can be done by anyone.
You'll need LED spool(s), 1/2" clear shrinkwrap (in diameter - I used Insultab 3005000C1A5 HS - 1/2" x 50' Clear Polyvinylchlorid Heat Shrink Tubing), silicone sealer. 1/2" aluminum channels or 1/2" metal strips for rigid install.
Step 1: Flexible Lighting Build
I wanted to wrap the LED's around wooden posts we have going up the front stairs. First I figured out how long I wanted the strips. I used waterproof LED's, but after a year of them being in, I would not do that again - I'd go with the non-waterproof ones. Why? Because these are on stairs, they may get kicked, bumped into, etc. I wanted extra durability, so I also sheathed the LED strips in clear shrink-wrap. I could have used the non-waterproof ones and saved time and money. The silicone covering on the waterproof LED's sticks to the clear shrink-wrap. I used soapy water as a lubricant to slide them in. After a year in the sun, the "clear" silicone covering the LED's has started to yellow. I've seen this on ALL waterproof LED spools that are exposed to the sun. The silicone covering yellows. So if the LED's are exposed to the sun, waterproof with clear shrink-wrap.
Cut the length of LED required. Solder on the wires (hint - use liquid flux on the LED's and wires - the solder will bond instantly.) Cut shrink-wrap 1.5" longer than the LED strip. The next step can be pretty or not - mine was, er, not. But it's out of sight and after a year, it's still waterproof.
TEST each LED before the next step. I assembled all I needed at one time.
Slide the LED segment into the heat-shrink. Leave equal amounts past each end of the LED's. Assemble all of them. The next step is messy, so do them all at once. Wear gloves. Put the end of the silicone into the shrink-wrap until the tip touches the LED end. Squeeze silicone out and pull the silicone tube out at the same time, leaving a "plug" 1/2" long of silicone. Do the same for the wire end. Don't go so far that the silicone is coming out of the heat-shrink.
Next, use a hair-dryer and shrink the tubing. Aim all over and shrink uniformly, from the inside outwards. As it shrinks, the silicone will be pushed outwards. Leave the non-wire end alone - you'll use that to mount the light. For the wire end, I formed the silicone to a cone.
Step 2: Fixed Lighting Build
This is when you need the LED to keep a shape. Under a step for a long, straight run. Under a railing. Basically UNDER anything.
I needed to tuck a light under a landscaping brick overhang. It's invisible, but would look really nice. If you look at the brick stairway photo, it's the one on the bottom step. For this I took a metal galvanized plate, ground and sanded the area where the LED would stick so it would adhere, and stuck on the LED (after soldering on the wires and testing!) Then I slathered on silicone. See the photo - what a mess. But it's out of sight, and almost TWO YEARS later, it's holding in place. Photo #1
For long runs I use aluminum C-channel - an 8' section is around $7 from the big-box stores. Stick the LED strip to a side or the top - the reflected light looks different depending where you mount the LED's (on the inside left, top or right of the channel), so experiment with the look you like. After it's stuck in place, slather on the silicone. This insures the LED's stay in place. Important: You should use waterproof LED's here, as they are out of the sunlight (won't yellow), and they'll stick to the Aluminum channel. Make sure you seal the ends. On my deck stairs the wires are run through small holes drilled in the wood risers. On the brick stairs/wooden poles, the wires are buried in the dirt. I have used a variety of adhesives and caulks - the Aluminum eventually falls off. I wound up using Aluminum nails to hold the rails on the stairs. If the LED's are mounted to the C-channel top, pre-drill holes through the front and out the back of the channel, low enough so you just miss the LED's. You only need three nails for a typical wide stair. If the LED's are mounted on the sides of the channel, you'll need to pinch the C-channel between the nail and bottom side of the tread, then tap the nail up to "lock" it in place. Photo #2
The most complex build was under the handrails. These are iron, and on either side of our front door landing. The bottom is only a few inches above the concrete. I wanted the light to spread out, not just down, so aluminum C-channel was out. Here I used a 1/2" wide piece of metal - $3 for a 4' long section. After sanding and cleaning the steel, I stuck on the LED's, then encased the entire run in clear heat-shrink. Sealed the ends with silicone as done previously. I mounted them with black tie-straps, making sure the straps were not covering any LED's. I used one strap every 8". Photo #3
Our deck overhangs our pond, and I wanted a downward pointing LED strip - this is 8' long in an aluminum C-channel. Photo #4
Step 3: Planning, Execution, Final Thoughts
Of course you'll want to test all the LED sections before mounting and after - you don't want to undo several steps because you forgot to test! For the stair lights, I spliced each light into a run of wire, sealed each connection, and the next day buried all the wires in the landscaping under the lava rock. For the railing, I ran the wires down the side - they are invisible unless you look for them.
You're dealing with low voltage and a low voltage lighting transformer, so you're not going to be shocked or hurt. There are a few reasons for making sure everything is sealed - if the LED's get wet, they can short out. If you get water in the heat-shrink, you'll probably get mold or algae. The electricity can drain into the ground, causing corrosion and shortening the life of your lights.
How powerful a transformer do you need? 5050 LED spools come in 30, 60 or 120 LED's per meter. 16.4 feet / 5 meters per spool. Or another way of putting it, 150, 300 or 600 LED's per spool (Don't use 150! They are too far apart. From a distance, the 600's look like a continuous light.) Different manufacturers give different power requirements. In addition, RGB led's draw much more power because each LED is actually three LED's (Red, green and blue.) White is created by all three lighting. So RGB LED's draw up to 300% more than a single color LED.
LED's are in segments - these are indicated by "cut" lines - where it's safe to cut the strip. Different LED densities have different cut lengths. For example, with 300 LED's per spool, the cut line is every three LED's.
There are plenty of references on the web to calculate this. Unless you're doing an extreme amount of LED lighting, you can get away with a small outdoor low voltage transformer. You MUST use one for outdoor use. Things get more complex when to start lighting entire spools. For example, we trimmed our entire house in white LED's. It took 6 spools. I ran individual pairs of wires to each end of every spool. That's because the current and voltage drops along the run of LED's. If you wire spools together, the first LED will be bright, the last one will be much dimmer. Again, check the web for wiring and power calculations. Our front stairs, landing and more are lit by a small transformer. The back yard has 18 DIY LED light's on stands, stairs, the deck and more - all on one transformer.
Simple calculation - look up the total wattage for the spool of LED you plan on using. Most 300 LED 5050's use 72 watts. $60 buys you a 200 watt transformer. So you could power two, 300 LED spools with a room to spare for $60. I recommend the 300's for most uses - unless you have money to spare on transformers.
One final thing to think about: how much light is needed? If you look at my front stair lights, there are 9 LED's per step (or three LED segments per stair.) Under the railings there are three feet - around 36 LED's per side. This is plenty to walk by, especially on the stairs. If you need more light, then you have options: Use longer LED runs. Use higher density LED's (600 instead of 300) or use 24 volt LED's. 24 volt LED's cost considerably more, and you'll need a different power supply setup. For maximum brightness, I'd use the more dense LED's (600 per spool)