Instructables

DIY LED Replacement Bulbs for 12 Volt Landscape Lighting Wedge Base Bulbs

Picture of DIY LED Replacement Bulbs for 12 Volt Landscape Lighting Wedge Base Bulbs
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A while ago I decided to minimize our energy usage using LED lights wherever possible. Why not start in the front yard? I was using a 500 Watt supply and now use a 44 Watt supply!  I looked online for Wedge Base LED Bulbs. I saw lots of fancy circuitry and weatherproof housings that were going into an enclosure on a regulated 12 Volt supply.  They provided dim light  and were not cheap! The cheap ones are a few dollars now. But you can make one for about 25 cents in materials. They also don't combine colors. We need to make a Wedge Base Bulb that will run comfortably on 12 Volts. This integrated circuit requires four components. In this case they will all be diodes, hehe.  

So here is what you will need to have on hand:
An existing 12 Volt landscape lighting configuration, Malibu, Toro, ect.

Materials:
White 5MM LEDs ($4 per 100, Ebay)
Perforated circuitboard ($4 board, Radio Shack)
18 gauge copper wire
Rosin Core Solder for electronics


Tools:
Soldering Iron
Dremel Tool (possibly a coping saw)
Wire Cutting Dykes/Stripers
Small Needle Nose Pliers
Heat Dissipators (hemostats, alligator clips)
 
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Step 1: Cut the PerfBoard

Picture of Cut the PerfBoard
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Cut the PerfBoard into strips. The strips must be the width of a Wedge Base Bulb. So mark each fourth row of perforations for cutting with a ruler and a thin Sharpie. You might want to double check your particular board with one of the Wedge Base Bulbs for width but this should be accurate. Then cut with your Dremel using an acceptable cutting attachment. I used the detachable wheel for metal. Don't forget to wear some breathing protection of some kind. A coping saw may work as well. I tried shears and wire cutting dykes with poor results as shown. When the strips are properly cut they will have three rows of perforations as pictured. Then clip each strip into sections with wire cutting dykes, or Dremel. Clip each one off at the 14th row. This will give you the right size and shape to mount 4 LEDs.

Resources:
http://en.wikipedia.org/wiki/Perfboard

thinders7 months ago

Love it .........

I've ordered all the parts from Amazon.

Including Bridge Rectifier Diode 2W06 2 Amp 600 Volt Full Wave Rectifier

I will be using 4 ea LEDS

In a Malibu

http://www.usalight.com/Malibu-Canterbury-Path-Lig... (or similar)

I want to see the brightness / color with / without the Bridge Rect.

Your set up, the LEDs are in series ... A ---> C ---> A ---> C

With the Rect I presume I can do either Series or Parallel (AA CC).

Assuming the Rect is marked (or I measure) for + / - (or I measure with a VM), I can't recall how the diodes are marked.... I seem to dimly recall that one of the LED leads has a "step" at the base.

Lastly ........ I was thinking "where can I test all of this" and recalled that my doorbell chime is on a 12VAC transformer .....so I will have a test circuit right in my basement :-)

DIYtode thinders7 months ago

You cannot do series or parallel. Stick with series or your LEDs will burn out. The rule in this project still applies: put 4 LEDs in series. The full wave bridge is worth it. The flicker is gone! The bridge will be marked in some way to indicate the (+) output. In rectangular or circular cases the (+) is opposite the (-) which means the other two are the input, and go to the transformer wires. Sometimes the input leads are marked with tildes (~). If you have any problems post back and I will help you. The test should work OK. My unit is bright enough to allow me to line the inside of the lamp with a frosted plastic sheet and a warm gel filter and still I have a very bright light. The harbor freight LEDs are in vertical columns. You break the series trace for every column then wire in series. If you are just using regular single LEDs, just line them up all the same in series i.e. short lead to long lead. Long is positive. If you use the rectifier, it will work one way and not the other. No problem, just flip the circuit :-) But keep them in series (long lead from the first to short lead on second, and so on...) or you will have a burnout.

04_final_result.jpg01_rewired_columns.jpg02_front_b4_insertion.jpg03_board_inserted.jpg
All4FunOC (author)  DIYtode1 month ago

Nice work! Break it down bro! And then post a link to your instructable. I've been messing with my new one for like a year.......I have the urge to wrap it up and publish. Thanks for posting.

DIYtode DIYtode7 months ago

Wiring diagrams that may help. Don't forget All4FunOC's warning, you must use identical LEDs.

schematics.jpg
DIYtode8 months ago

Very clever! Following your line of reasoning I converted the main panel from the 27 LED harbor freight worklight into a 24 light array by cutting the printed circuits and hooking each parallel set of 6 in series. I plan to install it into a standard "jar" porch lamp. Your LEDs should be brighter and the flicker will be mostly gone if you add a full wave rectifier to the circuit. Example is Radio Shack 2760268. You can get these very cheaply online, anything rated .5 amp or higher and 50 V or higher will work.

All4FunOC (author)  DIYtode1 month ago

My bulbs don't flicker. Just a nice smooth glow. I'm guessing the Malibu transformer has a bridged rectifier. My reasoning is low voltage and many small arrays. This allows the remaining arrays to function should there be a failure in one or more of them. Large arrays = higher voltage = less safe. So did you do an instructable on your porch lamp?

drums1146 months ago

I was thinking about this. Can't you just take a set of old christmas lights, cut off 4 of them, strip the wires off the 2 ends and push them into the light socket? Would that work?

All4FunOC (author)  drums1141 month ago

Assuming you're talking about a 12 volt Wedge Base Socket, then yes, it might work, but not well. I wouldn't want to try it 16 times that's for sure. And that would depend entirely on your old Christmas lights and not my cool bulbs, hehe. Outdoor lights have to deal with moisture. Connections must be solid. Besides the light goes where the bulbs point. If it works, you will need a tree to hang the LEDs and direct their light. It seems I have made the tree and adorned it too, hehe. Peace.

thinders6 months ago

What is killing my LEDs ?

I followed the design, the LEDs are in series + to - , 4 ea per lamp. I used a single 600 V / 2A rect on the 12VAC output to provide DC to the 7 of lamps, output of the rect is 11.4VDC. Now all the LEDs are "dim" ........ Attached is a shot of 2 sets of 4, powered by a 12 vdc battery (spare Verizon FiOS 12 lead / acid ). You can see that 4 of the lamps are bright ....the other 4 are dim .......

What tests could I run on the existing LEDs to determine what is causing the failure ?

IMG_20140512_150643_833.jpg
All4FunOC (author)  thinders1 month ago

I'm guessing you have figured it out by now. This instructional is on a simple T5 bulb construction. If you did follow the design properly then it's not the LED array's (bulb's) fault. It's the amount power applied to the circuit. My array is designed for 12V AC/DC. But LED's have a voltage operating range. This allows for an amount of dimming, or brightening, as the voltage/current increases, or decreases, within that voltage range. The 11.4V bulb is operating properly. I'm pretty sure what you are seeing is simply the difference between applying 11.4V (dimmer) to the circuit, or 12V (brighter).

FYI: Power Supplies aren't exact voltage. An average rating is +/- 5%

Sorry for taking so long to get back to you.

thinders thinders6 months ago

I should have listed, here is the LED that I used ....

http://www.amazon.com/gp/product/B00JEGKZ9C/ref=oh...

  • Forward Voltage(V) 3.2-3.4
  • inant wavelength(mm)K:5000-6500
  • mcd:16000-20000
  • Power Angle (deg):120-140
drose251 year ago
Am I missing a step? Malibu and almost all traditional landscape lighting transformers output 12v AC. LEDs are DC devices. Usually a diode or bridge rectifier is used to convert the AC output to DC for LEDs but I'm not seeing it here...if you have these running on straight 12v AC I'd be curious to hear about their life span.
All4FunOC (author)  drose251 year ago
You are right about the AC part. No bridged rectifier in low voltage Malibu transformers. But the white ones work just fine. I haven't had to replace a single one. Now the experimental mixed color ones are a different story. I stuck with the same LED format instead of adding a fifth light. I'm liking the white anyway. So I'm good. They are still working great!
This was bugging me so I researched it. :D Apparently you can drive LEDs directly from AC as you've shown here, but it poses some potential problems. The first is the LEDs only light on one of the two alternating current cycles, so they are much dimmer than when run on DC. The other is LEDs usually have relatively low breakdown voltage and current tolerances and they can often be killed while trying to block the "wrong" current cycle. That problem can be fixed by just adding a regular diode to the cathode (negative) side of the LED series. It will block the reverse current from reaching the LEDs. The dimming part can't be fixed without a bridge rectifier, but they make really them small and cheap these days so they can be easily integrated onto your board or in a fixture if brightness was an issue.

Thanks for this instructable, BTW. I really like the way you used the perfboard as a T5 wedge base and neatly bent your LEDs for light dispersal. That was ingenious!
roger5051 year ago
I love LEDs but for landscape lighting that color is horrible! Get some better LEDs with some good color or stick with a 4W halogen.
All4FunOC (author)  roger5051 year ago
Well thank you for stopping by and making your "positive and constructive" comment. But if you had actually taken the time to read that which you claim to dislike. You would have found that one may use any color he/she chooses. LED's lighting do take time to get used too before a person can love them. Now I not only love them but use them as well. Surely your great love of LED's has brought you more than a suggestion to stick with a 4 watt halogen? I'm being nice, so, ...Have a good day.
Hoping somebody happens to read this and can answer it. Why no resistor? I'm asking because I honestly don't know, everybody stresses that you need to have a resistor for LEDs to limit the current.
All4FunOC (author)  nameless12121 year ago
That's because there are enough LEDs in the circuit to handle a 12 volt load. If there were two LEDs instead. A Voltage Dropping Resistor would be required to adjust the load so that the now excessive current is handled by the resistor in the form of a voltage drop. More in-depth details can be found on the links on my pages. Have fun!
Nice work. I've been slowly replacing every bulb in my life with LEDs as they go out or I just find some free time on my hands. The hard part is getting adequate light output in all directions without using a lot of LEDs.
All4FunOC (author)  Kurt E. Clothier1 year ago
Thanks! Yeah, four LEDs work great for this though. They are bright and the light shoots right out at ground level. I like the Warm White Corn bulbs. But my kitchen runs on 6 3x3W LED downlights. I had to detach the spotlight faces and Dremel down half the oversized heat sinks to expose the light, hehe. Now I'm after 1" E27 extensions for them.
nyktunr1 year ago
Have you considered sanding the outer surface of the LEDs to get a more diffuse light from your four diodes? Nice energy-saving hack! :-)
All4FunOC (author)  nyktunr1 year ago
I hadn't thought of that. Now we have an option between standard and straw hat LED diffusion.