Introduction: Inexpensive Garage Lights From LED Strips

Picture of Inexpensive Garage Lights From LED Strips

Hello all you happy people. Welcome to my first instructable.

This project came about as I recently rebuilt my garage and found myself in need of complete lighting throughout.

I had two main objectives: I wanted bright/even coverage and I wanted to do it as inexpensively as possible.

For a number of reasons I wanted to use all LED lighting for my project but the commercial products were cost prohibitive. At the time of this writing, 4 foot shop lights are going for $40 and higher. I did some research and before long came across inexpensive lighting strips from China. The strips are sold in 5m lengths (16.5 ft) and can be found on ebay for $5-7 each. But how to use them?

After a lot of thought, I came up with the idea of putting them directly onto my trusses. This would give me even lighting throughout and a clean modern look.

I found that one LED strip wasn't bright enough, so I added a second for more light. This is probably enough for general lighting but I wanted MORE POWER and added a third. Why not at this price, right? To give you an idea of the coverage, my garage is 24'x40'. I'm putting lights on 5 trusses and they are 8'6" off the ground.

The other piece of the puzzle is powering the lights. The LED strips run on +12vdc and require an external power source. You can easily buy 12v power supplies but I'm trying to go cheap, right? So I used old discarded PC power supplies. Cost? Free!

You won't need to know electronics for this project but you will need some basic soldering skills.

Let's begin!

Step 1: Prep the Trusses

Picture of Prep the Trusses

Although the light strips come with adhesive, I found that it wasn't strong enough to support the weight of the lights when mounted facing down. Therefore I needed a better solution. Through trial and error I ended up with Scotch outdoor tape. This stuff is super strong and holds in extreme temperatures. It is 1" wide and works perfectly for attaching three LED strips to a truss.

Grab a ladder and roll the tape along the bottom of the truss. Only roll out as much as you can reach so that the roll doesn't fall to the ground and get dirty. Place the tape directly on the center of the truss.

I used a small roller to securely press the tape onto the truss. I think I bought this roller years ago for sealing the edges of wallpaper. A rolling pin would probably work as well or even better.

Step 2: Add the Lights

Picture of Add the Lights

A note before we begin. I purchased LED lighting from two different sources on ebay. One had power connectors on one end, while the other had power connectors on both ends. Either one will work fine. Roll your LED strips so that the power connectors all line up in the same spot. This will simplify your life when it comes time to connect the power. In other words, if you have the single ended type, don't put one down one way, then another the opposite way.

Peel off some of the protective backing on both the tape and the LEDs. I found it worked best for me to run the center LED strip first then butt the other two along side of it. Do this step anyway you choose. One strip at a time if you like. To save myself going up and down the ladder a hundred times I did it like this:

Ran tape down the entire length, using the roller as I went.

Starting at one end I pulled an arms length of tape backing, Then pulled the backing tape off an arms length of the first LED strip and pressed it onto the center of the tape. I followed that by doing the same for the remaining two tapes.

You will now need to firmly press the LED tape onto the outdoor tape to ensure a good bond. Do not use a roller for this step as it may damage the strips. I tried using the palms of my hands with fairly good success, but the best solution was using pressure from both thumbs.

I repeated this step until I had covered the entire length of the truss.

It's very unlikely that the length of LED strips you bought will fit the truss perfectly. So what do you do? One of the many cool things about these LED strips is that you can easily cut them to length without damaging them. Each strip has little copper pads every few inches where it's safe to cut (and join) strips. Take care to center your cut.

Step 3: Run the Power Line

Picture of Run the Power Line

Now that the strips are up and looking good, you're probably excited to light them up. Time to run the power lines.

For this step I used 18 ga speaker wire. It was perfect for the job but you could use whatever you like. The wire just has to be able to handle the combined current load of the lights you are sending through it. Not a big concern unless you are running a lot of lights.

This is where you test your soldering skills.

Strip a little insulation off all the leads, then twist them together red to red and black to black. Simple eh? Solder the leads together. I'd strongly suggest you invest in a few pieces of shrink tubing for this project. Makes things tidy.

You could avoid soldering by using wire nuts or crimp-on solderless connectors. I prefer solder for the solid connection.

I used low voltage staples for my runs spaced about 3 ft apart.

Note: If you are making a long run that requires multiple LED strips to cover the distance, do NOT daisy chain or power one from another. If you do, the more LEDs you add the dimmer the lights will become. Take your time and wire each strip individually. In other words, run the power in parallel, not in series. By wiring in parallel, each LED will have full brightness. On the first truss I made individual power runs for each of my 9 LED strips. This was way too much work. After that I wised up and ran one power 'bus' the length of the truss and tapped off the bus to each LED strip. I used the same 18 gauge speaker wire for this. Much less wiring, much less ladder time, much neater installation. Live and learn eh?

Step 4: How Many LED Strips Can I Run Off of a Power Supply?

Picture of How Many LED Strips Can I Run Off of a Power Supply?

Eventually you will find yourself asking this question. Here is how I determined how many strips per power supply.

On the side of most PC power supplies there will be a chart that tells you the current load per voltage rail. On my power supply photo you'll want to look at the intersection of the YELLOW +12V Column and the 300W Output row. It reads 14A. In simpler terms, this says that when using a 300 watt power supply the 12volt yellow wires can output up to 14 amps of current.

Okay, now that we know how much current we have to work with, the next question is: How much current does each LED strip require? A search of the LED specs shows that each 5M strip draws 30 watts of power. Interesting, but still doesn't answer our question. How many 30 watt LED strips can I run off a 14amp power supply?

To answer that question I searched online for a power calculator. I entered the value of 12 for the voltage we're using, and the value of 30 for the Power of each LED strip, hit calculate and it tells me that each LED Strip will require 2.5 amps of current.

So to answer the question of how many lights can I run off a power supply, the answer is..... it depends.

In our example the power supply we used can output 14 amps. Divide 14 by 2.5 and you get 5.6. Or in other words, you should easily be able to run 5 strips off this power supply.

I also said the answer depends. It depends because power supplies will vary in their current ratings. The example I used was just for this one particular power supply. Many dedicated 12vdc power supplies are rated at 30 amps for example. More amps = more LEDs. Look at the label and do the math.

Step 5: Make the Power Connections

It's time to connect your LED strip lighting to the PC power supply. There are a couple of ways you could do this and now is the time to make that decision.

Hardwire: Connect the power leads of the LED strips directly to the PC power supply. This is an okay solution but what happens if you ever need to replace a power supply? You'd have to cut and resolder/crimp a new one in place. There's nothing wrong with this solution. I just choose the next option.

Connectors: Solder a PC power connector on the LED power ends and connect it to the power supply. This way if the power supply dies, you have a quick disconnect. Be up and running again in seconds with minimal hassle

At this point we should talk about the power supply. A PC power supply is not instantly ready to use for our project. We need to make one quick modification for the power supply to turn on when plugged in.

This guy does a pretty good job of converting a PC power supply into a source for your lights. Remember, we're only interested in using the +12 volts.

Once the power supply has been modified and you have your connection on the LED lights, connect the two and plug it in.

Since this was a new lighting installation and my only source of light, I installed switched outlets between my trusses to power the PC power supplies and in turn, the LED strips. Walk in the door, flip the light switch and let there be light!

Step 6: Final Thoughts and Sources

Picture of Final Thoughts and Sources

I'm really happy that this gamble paid off. The lighting is bright, even, and fantastic. I believe I spent maybe a tenth of what a commercial application would have cost.

The LEDs are available in all colors but two flavors of white. Cool white and Warm white. Cool is similar to florescent lighting where Warm is closer to incandescent. I went with all Cool white. While it looks terrific, I think it's slightly too blue. If I were to do it over again I would have gone 2 cool, 1 warm.

They also come in a waterproof version. The non-waterproof ones are a bit cheaper and that's what I used.

I ran out of lights during the project and had to buy more from a different source. The second ones were cheaper but had two small dead spots. Get what you pay for? Regardless, dead spots are not a big problem. They can be easily cut out and replaced.

Even though there is plenty of light, I think it still needs more light directly over the workbenches. I like LOTS of light. But your mileage may vary. I'm going to convert my old shop light into LED using this same method.

One source for lights: They've only been up for a week but seem to work fine.

Just pick one that has free shipping and a good rating. Expect a week or two shipping from China to the US.

You can get them from any of a hundred vendors on ebay. Do a search on: 5M 300LEDs SMD 3528 5050 5630 3014 RGB Flexible LED Strip Lights

If given the option, choose the 5630 non-waterproof variety. At least that's what I used.

Computer Power Supplies: I work in IT and have access to lots of discarded computers. That's exactly what you want. Ask the IT guy at a nearby school, or business or anywhere that's large enough to have an IT staff. Be friendly, bring candy, most likely they'll have a few laying around that they'll give you.

The other option is to buy a dedicated 12vdc power supply from ebay. Search for: 12v regulated power supply. This one sells for about $20

If you go this route instead of the PC power supply, just connect the red and black wires from your LED lights to the power terminals on the power supply. This would honestly be an easier solution but I had easy access to free power supplies so I saved myself $100+

The tape I bought from Amazon. I looked at a few China knock-offs on ebay but didn't trust the quality. Go with genuine 3M.

Because this project uses low voltage DC current, it is both safe and legal for you to do yourself. The most dangerous part of this project is standing on the ladder.

One last thing. This project is fairly labor intensive. Expect a lot of ladder time!

This was a fun and rewarding project. I hope you find this Instructable useful!

In hindsight....

I was about halfway through this project when I realized that it would be perfect running under solar energy.

Why/how? The entire thing runs on 12vdc the same as your car battery. Solar panel kits are getting really cheap and it would be pretty easy to connect to the lights. While this wouldn't work for lighting your house, for occasional garage lighting I think solar would be a perfect solution. Another project for another day.


John Harwood (author)2018-01-02

I have done this before with under-cupboard down-lighting in my kitchen... Result? Low lifespan of the LEDs. Then I learned about LED drivers... Not just transformers from mains to 12 volts, but electronic devices which take care of the regulation of the voltage. Dirty DC supplies will kill LEDs. The solution? Run the buggers off a 12v battery, which will give you weeks of lighting before needing re-charge. Then just re-charge it. An old battery which is not up to cranking your car engine any more will do the job. If you need the lights to be controlled via your normal light-switch, consider using a relay.

SergeyS9 (author)2017-12-20

@happydupa wrote: "Although the light strips come with adhesive, I found that it wasn't strong enough to support the weight of the lights when mounted facing down". It's is because the light strips are not designed for this use - it overheats and falls. And it overheats because it must be cooled. To do this, light strips must be glued with an existing adhesive to the metal surface. Without proper heat dissipation, LEDs overheat, prematurely lose brightness, and then fail. Instead, you use a foamed adhesive that is a heat insulator.

You made a fire-hazardous project.

If we forget about the legal side of the question, the simplest solution is to install aluminum strips on the wood beams, and then glue light strips to it.

Sorry for the bad English, I'm from Russia :^)

Electrical Engineer

ChristopherM55 (author)SergeyS92017-12-20

While searching for the lights on EBAY, I noticed plastic clips available for mounting these lights. The clips go across the strip and are screwed in place. They seem to be a better mounting option.

SergeyS9 (author)ChristopherM552017-12-21

Yes, ChristopherM55, plactic clips looks to be a better mounting option. But I never use it, and have no issues with mounting.

As a right way, use a special U-Style Aluminium Channel Holder for LED Strip (example) You can find it in up to 2,5 meters (8,2 f) length.

As i minimum, use a Aluminum Flat Strip Bars (example) as a base for LED Strips. Strip Bars are fastened to the base on the screws, then LED Strip is glued on it. And no problems with adhesion and heating. But U-profile (mentioned above) much better, because have a special translucent polycarbonate plactic cover.

ErikH57 (author)2017-06-22

Interesting project, but I'm a little stuck on the "low cost" aspect of it. You said the LED strips were $5-7 per strip and you used 9 strips per truss. From the pictures I see 5 trusses, so that is 45 LED strips total, which at $6/strip not including shipping is $270 just in the lighting strips.

Now each strip is 16.5 feet long, so in 3 lengths per truss (you used 9 strips on each truss in a 3 side by side configuration) and 5 trusses that is about 247 feet of length. I looked up your Scotch brand tape that you used at my local HD and it comes in 12.5 yard rolls at $15.97/roll. You would need 7 rolls to cover your project, so that is about $112 in adhesive tape. We are now at $382 for the project.

Next you need power supplies. Let us negate what others have said about derating the power supply for longevity. You said you could light 5 strips with one 300 W power supply. You had 45 strips, so that is 9 power supplies! You said you got them for free, so that is great, but if someone had to buy them, a 300 W power supply is about $30. That is $270 for the power supplies. Now the project is at $652!!! I am not going to count wiring because if you used commercial fixtures you would have to wire them too.

Finally...4 foot led shop fixtures are about $40 at your local HD. You could have bought 16 of those fixtures for what it cost in material for this project. Now I would have to get the specs for those fixtures and calculate your layout, but I would think you could get more than sufficient light output from 16 or less fixtures and those fixtures would likely last longer than the strip lighting mounted directly to the trusses.

This is an interesting instructable, no doubt, but I am not sure it is really a cost savings unless you have a pile of power supplies laying around.

MichaelS891 (author)ErikH572017-06-22

I get these strips on ebay regularly for about $1.25 apiece. 12v power supplies can be similarly bought for under $10. If you price your project at a brick and mortar its never going to be inexpensive.

ErikH57 (author)MichaelS8912017-06-22

I priced my 300 W power supplies online and used the OP price point for the LED strips that he used of $5-7 each. The cheapest 16.5 foot LED strip lighting I am finding on Amazon is actually about $25. I would love to see what source you are finding "quality" 16.5' LED strip lights for $1.25 each! Most inexpensive 300 W 12 Vdc power supply I can find on Amazon is $18.81. So again...I would love to see what "reliable" 300 W, 12 Vdc power supply you are getting for $10. exactly was I pricing my stuff from a brick and mortar?

ChristopherM55 (author)ErikH572017-12-20

The strip lights are very cheap on EBAY when buying direct from China and they ship for free. The only drawback is waiting a few weeks for delivery.

kevinecker (author)ErikH572017-07-29

Don't use Amazon, you can find the strips much cheaper on Ebay

jr45738 (author)2017-11-14

this is brilliant! it's just what i need. i want to back light a bathroom mirror.

two questions:

1, is one white strip bright enough to light to around a 3' by 4' mirror? the light will

be set back about 3" behind the mirror, mount on a frame and shine out on the wall. the mirror

will be set out from the wall 2" to 3" also can it be dimmed?

2, i will have a 120v power source. will the 12v power source connect

to that?

thank you,


ChristopherM55 (author)jr457382017-12-20

The strips come in 1M, 5M, or 10M length. Your mirror is 14 feet around, so the 5M (16.4ft) would be the size you need and then cut it for your length.

jthornburgh1 (author)jr457382017-12-14

Jule, I made a smaller light for my work bench, similar to the size you described. I was surprised that a single nine volt battery lit the entire string of LEDs. I reused a cell phone battery charger for my power supply. Good luck.

BrightSolderJoints (author)2017-09-19

"safe and legal" wiring - ahem - Please invite your homeowner's insurance agent over to inspect your work. Please invite your city's Electrical Inspector over to inspect your work. Your wiring and your lighting are more code violations than I can count. If you value your family's life and you want your homeowner's insurance to pay for fire damage, then you must only use UL Listed & Labeled light fixtures.

What code violations are you talking about? What danger is there to the families life? I invited my cities electrical inspector over to take a look and he thought it was terrific. I mentioned your concerns and he shook his head and I'll just omit the rest of the conversation for your sake. So again, since you seem to be in panic mode about something, please explain your fears and quote your sources and expertise.

You are simply lying about an Electrical Code Inspector approving your Do-It-Yourself-Wrong lighting system. My expertise is Master Electrician doing commercial and residential for over 30 years. The code violation is simply the improper installation of home made light fixtures that are NOT code approved Listed & Labeled UL Approved luminaries.

Hold your horses! Maybe he's in a different country! (Or even state or province)

It's 12v power. You're good here.

No, you are wrong. Only part of the circuit is 12 VDC. The other part of the circuit is the 110 VAC power supply that converts 110 VAC to 12 VDC. Low Voltage circuits can cause a fire just as easily as 110 VAC. Don't believe me: put a metal jumper wrench across the terminals of your 12 VDC car battery. You are using the mindless illogical argument of "a Red Herring". You are not responding to the comments I made. The Do-It-Yourself-Wrong wiring project is NOT the installation of a code approved Listed & Labeled UL approved light fixture system.

Leave m red herring out of this. Im sure that powere supply is fully certified and protected. Not to mention ths outlet its plugging into. The lights themselves woukd get no hotter than a baby toot. What gets hot on your store bought lightbulb replacments are the controls. They would concern me more than this setup. Car battery compaired to a pc power supply is like compairing a bycicle to a motorcycle.

unitedkingdomliam (author)2017-11-07

I have been using these for Five years in my Garage and in the bedrooms of my house Solar will be for my Home and shed in Poland.

guerroloco made it! (author)2017-11-05

I used an HP server power supply (750 watts) to run 8 high-bright 5630 strips

MattM370 made it! (author)2017-09-26

Chapter 2:

i departed again from this instructable...

1) i used more expensive lights, waterproof, 5050, 120v, so they all just plug into a long power strip.

2) they're in my garage, but my joists are covered, so i chose to put them corner to corner. this allows me to plug all of them into a single box rather than somehow accommodate multiple plug-ins along one wall. the effect seems to be to put more light in the center of the garage, which is where i probably want it, while giving more light to the corners than before. i still have two open plug-ins so can add a couple more strips if i want.

3) the lights came with plastic U-clips and screws. i used those again directly into the sheetrock.

4) intended to replace the light with a receptacle, but found it didn't fit so added a box & receptacle as near to the center as i could and still attach to a joist. chose to leave the incandescent for now. i can unscrew it, or put a plate over the box later if i decide to.

a few notes:

1) used warm white this time.

i used 4 meter strips, which don't quite reach the corners.

according to my research and calculations, of which i'm by no means
certain, the lumen output one 3m/9-1/2' strip = one 4' T8 and about
1/5th the wattage. i think.

a friend is using some of these LED strips for his basement workroom, and i'm hoping to use some as undercounter lights in the kitchen, though i'm having an issue getting enough light. so far.

MattM370 made it! (author)2017-08-13

thought i'd commented earlier, but they never showed up.

i departed in quite a few ways from this instructable, but have been very pleased with the results...

1) i used more expensive lights, waterproof, 5050, 120v, so they all just plug into a long power strip.

2) they're in my basement workshop, not the garage.

3) the lights came with plastic U-clips and screws, so i screwed those to the floor joists.

a few notes:

1) i'd agree that all cool white is a bit blue for me. should have alternated with warm.

2) i used 3 meter strips, which don't quite reach both sides, i found it gives much more even light along that wall, but doesn't reach back into the rest of the room very well. or not as much as the fluorescents did. (FYI the before picture is a 3-bulb T8 fixture, with only two bulbs working) bad news is i'm more to forget to turn them off than i was the old lights. good news is, they take so much less electricity.

3) according to my research and calculations, of which i'm by no means certain, the lumen output one 3m/9-1/2' strip = one 4' T8 and about 1/5th the wattage. i think.

i'm now looking for the next place to put these, and i strongly suspect i'll find several.

Bradscopegems made it! (author)2017-07-24

This is the image with the LEDs at the top and the vertical stripes are the reflections.

Bradscopegems (author)2017-07-22

Thank you ! Your article inspired me to make a long-needed ceiling light over a kitchen worktop. I stuck 5 LED strips, each 2 meters long, and connected them in parallel to a 12v 10A DC laptop power supply. Because I did not want the light to glare over the dining table, I mounted the strips on an L-section extruded aluminium strip, so that the LED strip was mounted parallel to the ceiling and the vertical part of the L acted as a shade/ reflector. Unexpectedly, the aluminium's fine marks along the direction of extrusion diffract the LED light, creating a very pleasing appearance of 3D in the reflections, which I have tried to show in the photo attached.

Ozalid (author)2017-07-18

Excellent, I will try this asap!

Thorigol (author)2017-06-23

Here's a whacky idea - how about NO power supply. All you engineers out there can let me know what you think of this:

Take 10 of these strips and wire them in series instead of the standard parallel configuration. That's 12v drop across each for a total of 120v. And LED's are diodes after all, so in theory you can just hook them up, they'll light up for half the cycle and not for the other half. Or you could just put a fullwave bridge rectifier in front of the strips.

Of course this means some dangerous voltages so you'd want to use the waterproof strips which encapsulate all the exposed copper except at the ends where you'd want to take appropriate precautions to make sure there is no exposed wiring.

But with the safety issue address appropriately, shouldn't this work fine? I'd think you could even use a standard lighting dimmer with it. Comments?

brico63 (author)Thorigol2017-06-27

There's a flaw in tour theory. If you put strips in series, you'll still only be able to feed them 12 Vdc. Why? Because the 0 and +12 V lines run along the edges of the tape, like power rails, as you can clearly see if you enlarge the source picture ( That's why you can cut the tape anywhere. Between each marked cutting point you have three LEDs and one 39-ohm resistor in series between 0 and +12 V. And it repeats 100 times on the 5-meter tape, which means that each little section draws 0.3 W, or 25 mA. All little sections are parallel to each other, not in series.

So it you put anything above +12V to feed the strips, even if you put a thousand of them in series, you'll fry them in no time.

Thorigol (author)brico632017-06-29

I'm talking about putting the STRIPs in series. You are obviously correct that the LEDs within each strip are in parallel and that ain't going to change. That doesn't mean you can't put the strips themselves in series - I've done a little drawing with just 2 strips to show what I mean.

brico63 (author)Thorigol2017-06-29

Yes, you can put the strip in series, but for constant and predictable results, only in the typical way.

I made a drawing for you to understand how they are constructed. I arranged each section's three LEDs and one resistor vertically, rather than horizontally like on the real tape, to make the layout easier to grasp. You see that each of the 5+3 sections is parallel to each other, like the light bulbs in a kitchen fixture. Each section can be thought of as a tiny 12 V light bulb on a 12 Vdc supply, like all 120 V light bulbs in the fixture are parallel on a 120 Vac supply. That's why each section (or bulb) is as bright alone or parallel to 7 others. The tapes are connected end-to-end in a "serial" way, but the sections are all really parallel to each other on the whole string.

So you realize that the closer you are to the supply, the larger the current in the power rails. The power rails (red and black lines on the drawing) of the first section carry the current for all sections after (let's say 2.5 A for a 100-section tape), while the last section's only carry its own current, 0.025 A (25 mA). If you put two tapes one after the other, the power rails of the very first section of the first tape carry 5 A, and with three tapes they carry 7.5 A. That starts to be quite a lot for a tiny foil, I'd like to see the specs on that.

The writer of this Instructable had the good idea of using separate power wires for each strip, but I'm not sure he realized that he could thus prevent the strips from overheating.

I also reproduced your atypical connection. You can clearly see that no light will emanate from strip #1, as current only flows in the positive power rail. There won't be any light from strip #2 either, as the diodes are reverse-polarized. If you had correctly drawn your lines (like on third drawing), you'd get light for sure, but the brightness would be dependent on the number of sections in each strip, especially if they don't have the same number. The whole strip's brightness would change if a single section died. Finally, you'd need power supplies with different voltage outputs according to the number of strips. Not practical, and no good results with it.

A little calculation for your atypical solution. The tapes are connected serially, but within each tape the sections are still parallel to each other. Let's say that a 10-section strip is put in series with a 1-section strip. As the voltage drop across the three LEDs together is 11.025 V, that would use 22.05 V for two strips. On 24 V, that leaves 1.95 V for a combined resistance of (39/10 + 39) ohms, yielding a current of 45 mA in the LEDs of the second strip (but only 4.5 mA in each of the first, very dim). 45 mA is way too much for the LEDs, which will die at a quarter or less of their nominal life. That's an extreme example, but it shows how your atypical method will lead to poor output and reduced life. Putting 10 strips in series as you originally suggested would exacerbate the problem further. Even in the 5 against 3 scenario illustrated, only 18.5 mA would flow in the dimmer LEDs of the first strip, while 31 mA would flow in the LEDs of the second strip, shortening their life as well.

Thorigol (author)brico632017-06-30

Thank you for your thoughtful reply brico63,

I completely agree with your analysis.

My drawing was in error, I was careless and have fixed it below.

I have seen various LED strips that have other arrangements of LEDs and resistors than you have drawn, for instance one resistor per LED, but always across the power rails along the edge as you indicate. Thus the impedance across the rails of any given strip is a function of the number of LEDs.

I thought it went without saying, but as your numbers clearly show, my solution would only work if each strip in series has exactly the same number of LEDs. With that precaution, would you agree that it would work?

brico63 (author)Thorigol2017-07-01

Thorigol, yes it would work if all strips had the same number of sections, but it has so many disadvantages over the regular connection:

- It would take only one defective section in a strip to throw off-balance the whole installation. In the regular connection all you'd have is a localized dark spot. With your method you'd also loose intensity on the other strip and increase intensity on the sick one.

- The increased intensity would put additional strain on the remaining sections, resulting in a cascading effect that would eventually destroy the whole strip.

- You need a power supply adapted to the number of strips, rather than sticking with the standard 12 V.

- You must use identical strips with exactly the same impedance, otherwise you may get the same effect than having different number of sections.

- You have to plan your installation carefully to get as many sections in each linked strip. You cannot really change your mind and expand or shrink the project later on.

- Mechanical damage that would for example short + and - on a strip could potentially damage all other strips due to increased current, rather than just blow a fuse (if one was installed) or the power supply itself.

- And of course, higher voltage means higher danger for whoever may come in contact with the installation, and possibly fire hazards and insurance issues.

Frankly, I don't see why you'd go through all this trouble when the basic installation is so simple, safe and durable. For large installations like the one described here, a dedicated 12 V pair of wires for each strips is really the best thing.

Thorigol (author)brico632017-07-01

Again, you make good points but I can take issue with most of them:

- I've used these kinds of strips for several years and have yet to see an LED go bad. No doubt someday it will happen, but if the strips are long with many LEDs, the impedance change from one LED going out will be negligible, on the order of milliamps. The OP is running strips that are 40' long - it will take a lot of bad LEDs on strips that long to throw off balance enough to make any difference.

- The idea here is to NOT need any specially adapted power supply, but rather configure the load to run at line level. If you're concerned about too much current, you could use additional strips to further divide the voltage.

- I agree, every strip must be exactly the same length and the project would have to be carefully planned to make that work out.

- There is little chance anything would damage a strip to short out the rails, but if that did happen, or if over time enough LEDs went out, there could be a situation where too much current could flow. Therefore, such an installation would clearly need a fuse, and that would protect against any such hazard. That's what fuses are for.

- As for dangerous voltages, you'd really only see them at the line connection, which as I said, should be appropriately insulated. The potential across any given strip is exactly what it would be in a 12V power supply installation.

- Old computer power supplies as the OP employed are not without risks. They themselves have numerous failure modes which can include flame-outs. In several of my other LED installations, I used Zurik LED driver power supplies which are nothing more that well built boxes with a transformer, bridge rectifier, and a fuse; they work great but waste energy as dissipated heat and cost a fortune.

- I will grant that Electrical code and insurance issues may be valid reasons to not try this.

rv8flyboy (author)Thorigol2017-06-23

there is an issue with your thought, 12 Volt DC vs 120 Volt AC.

Thorigol (author)rv8flyboy2017-06-23

Yeah, as I said, LEDs are diodes, thus no conduction when the AC cycle goes to the wrong polarity, thus the LEDs would be lit only half the time. Or, as I said, use a 4 rectifier bridge in front of the LEDs to make DC (or at least 120Hz pulses all in the same direction).

ecochran3 (author)Thorigol2017-06-25

...Or wire the LED strips in parallel and in opposing polarities, so that half are forward-biased and the other half are reverse-biased. This would be operating them at 50% duty cycle and giving the illusion that all are powered simultaneously.

Thorigol (author)ecochran32017-06-26

You could do this, but then you'd need twice as many strips as the voltage would need to be divided by 10 for each phase.

As for any illusion, human persistence of vision would prevent anyone from seeing the difference between 120Hz and 60Hz, although some can perceive the flicker of European 50Hz.

JohnC430 (author)Thorigol2017-06-23

yes you can do that. Add a resistor in series to limit the current because the peak of the 120 Volt sine wave is 167 Volts. with a DC supply that 60 Hz is missing. even with full wave rectification you will still feel the 120 Hz. you will still need the limiting resistor. resistor value will be dependent of the current thru the diodes (LED's).

Thorigol (author)JohnC4302017-06-26

No additional resistor needed - These strips all have built-in surface mounted limiting resistors, that's how they make an LED that lights up with a 1.2v drop work at 12v. Your point about the higher peak potential is true, but those are very short periods of time where there will be higher current - if the LEDs are drawing too much RMS current, you could use 11 or 12 strips in series to further divide the line voltage.

brodiefairhall (author)Thorigol2017-06-25

Please do not try this.

with a full wave bridge rectifier (and probably a smoothing capacitor) you'll still potentially have your peak voltage destroying your LED's as it is going to be significantly higher than the RMS AC voltage.

The main concern I would have with this (if you don't electrocute someone) is burning your garage down. the water proof versions might protect you from getting zapped, but it wont stop that much voltage tracking internally and probably setting all that great waterproofing alight!

Thorigol (author)brodiefairhall2017-06-26

This warning is just plain paranoia. Even with 220v mains, you wouldn't have enough potential to bridge across any of the traces on these strips (which is what I'd assume you mean by "tracking internally"). Plus, the line voltage is distributed across all the strips so the potential across any single strip is still just 12v or 17v p-p. Plus, the waterproofing is silicon which isn't flammable.

That said, certainly one should use appropriate caution to fully insulate or enclose any exposed connections.

Epimethius (author)2017-06-23

120V is possible. I prefer the safer 12V. There are few code restrictions for low voltage. When you get to 120V all kinds of national and local codes and laws are involved, for very good reasons.

In the near future I except many more houses will be wired for dual voltage, low for LED lighting and electronics, high for power units - refrigerators, air conditioners, blenders, saws. You are simply ahead of the times.

mud1070 (author)Epimethius2017-06-28

I agree with you on AC & DC power supplies in the home. Excluding major appliances, everything in my home now is running DC via transformer
(phones, computers, modem, lights, etc.) which is frustration when I see one plugged in & being inefficient.

BastidgeC (author)Epimethius2017-06-24

We need USB charging ports at the wall!

cdavenport (author)2017-06-27

I did this, and it is cheap and easy! I have a friend who supplied me with several computer power supplies.

Chimonger (author)2017-06-22

This really looks very cool! But, complicated to get up there to wire it all, many power supplies.....and, unsure how it is less costly [counting time, effort, materials, AND power bill to support it?] ....than simply using ready-made shop lights, with LED bulbs already in them? What happens when the LED strips stuck to the rafter, dims, yellows, or loses LED function [as numerous types of our rope, strip etc. LED's have]?

Costco carries Feit 4' LED linkable shop lights, at $60 each. Plug'n'play.’-Linkable-LED-Shop-Light-with-Pull-Chain%2c-2-pack.product.100284402.html ; Home Depot carries a list of various sizes and configurations of LED shop lights, also plug'n'play, in a range of prices. Easy to remove and replace. LED "bulbs' configured to replace long fluorescent bulbs, even easier to replace [although, not all of those are very good quality, and can devolve into shutting off randomly].

For the look of professional, clean-lines, with no fixture to dust off, the LED strips attached under 2x rafters or trusses, could have a beneficial edge.

I'd suggest taking advantage of those LED strips ability to choose colors, to make some strips run various colors, like reds and yellows, to help reduce eye fatigue from the blue wavelengths in the cool whites.

Also, you might want to get an EMF/RF meter, to take readings on what kinds of electro-smog the LED lights and associated equipment are emitting, as those can be a health hazard, if one spends too much time exposed to them. Some folks use metal mesh over a fixture, to prevent fixtures emitting high levels of EMF/RF into a living/working space [kinda like little Faraday cages around fixtures, must be grounded].

Nigel Pearson (author)Chimonger2017-06-26

If a few LEDs in a strip die, you live with it. If the strip yellows (in about 20000 hours, so many years), you replace the strip. If the PSU dies, you recycle another one.
Your CostCo strips are tiny, and you would need three of them, side-by-side, for the same light output. These strips are 5m long for the same price.
Dusting? This is a garage, right. How often do you dust the lights in your current garage.

caltemus (author)Chimonger2017-06-22

Why are you even on this website? Also electro-smog is not a thing. You must be like that crazy dude from better call saul that's 'allergic' to wifi

marcgwathelet (author)caltemus2017-06-22

Yes, and it is actually the same misunderstanding they had for the Chuck McGill character in Better Call Saul, you would detect EMF only if the current is alternating, there is no EMF with DC, and so Chuck should have been unaffected by a loaded battery.

burzurk (author)caltemus2017-06-22

sigh...nailed it

About This Instructable




More by happydupa:Inexpensive garage lights from LED strips
Add instructable to: