So I have a couple basic outdoor fixtures that I've relocated to my garage ceiling that id like to convert to led, in part because I want a more even distribution of light rather than the energy savings. Also in order to learn a bit more about leds.

I'd like roughly a 150w halogen equivalent which is about 2400 lumens.

Which seems to be equal to about 22-25w led.

So I buy the LED (or do I buy multiple smaller ones?) and what ese? Heatsink, transformer?

 

Do LEDs come that bright? I just bought the brightest ones I could find and they were only 1600 lumens.

 

It all depends on what lights you choose. Some LED lights have a even illumination pattern while others are more focused or have hot spots. The need for a transformer or heat sinks will also depend on the lights you choose. Most lights, except for low voltage landscape lights, will have the power supply and heat sink built in.

 

http://vi.raptor.ebaydesc.com/ws/eBa...=1478537552266

So for example this link says 20w = 1800-2000 lm and 30w = 2700 - 3000 lm. I'm thinking the 20w would probably be fine. Is the "driver" they have in the link the only thing I'd need to convert from line voltage to led appropriate power? Are heat sinks actually necessary or can I get away with out one? Also how do you connect the heat sink to the LED ?

 

If unfamiliar with wiring and electronics it might be better to look at LED light fixtures and not individual components. Also, many Ebay LED's and especially the higher wattage square panels are not what their specifications say. Many produce nowhere near the light they claim.

 

I'm not familiar with leds. I have some basic soldering experience with home electric systems and electronics from ages ago in HS shop class.

But the point of this is to learn. This isn't an urgent job.

 

I would consider the design for the power supply to achieve overall energy efficiency much improved over off the shelf CFL or other technology to be for an undergraduate level or advanced high/trade school level electronics course.

I would consider the design for the physical LED layout and optics of a custom designed fixture to be for an undergraduate level or advanced high school level physics course. Each individual LED element (diode) has a relatively narrow "beam" or light distribution pattern. Also, translucent diffusers, including the outer bulbs of off the shelf screw in LED lamps, absorb some of the lumens of light output.

 

A lot depends on what your "basic outdoor fixtures" are.

My work recently replaced all the outdoor sodium lights with LED bulbs similar to this: <img src="https://www.greenelectricalsupply.com/images/products/thumb/VentureLEDRetrofit.1.jpg" width="150" height="145"/>

I think all they had to do was bypass the ballast. LED bulb puts out 6500 lumen but there are many choices of output and base type.

If your "basic outdoor fixtures" are glass-enclosed you might need to be careful about how much power you put in there in order to not overheat the bulb, damage the fixture, or worse.

 

I need to know the type of fixture you have. Is there a nameplate? LED conversion kits are available for almost every type of light fixture.

 

LEDs run at lower voltages and are DC. The driver converts AC voltage to DC and drops it down to the required voltage that the LEDs use.

As Electromen mentioned, there are many conversion kits available for a wide variety of lamps. Shineretrofits and SuperbrightLED are two good sources. Some conversion kits are as simple as screwing in a bulb, while others require removing/adding components. For most home fixtures the easiest path is to just use a screw in replacement lamp.

Heat is a killer of LEDs. Replacement lamps normally will have heat sinks built in if needed. If you are DIYing something, a heat sink might be needed.

Here is a picture of a 400-watt HPS lamp the I converted to LED. The LED had a good sized heatsink and fan on it. Driver was remotely installed.

Attachment 73299

 

The problem with screw in bulbs with these fixtures is that most of the light ends up pointing the wrong way since the bulb lays parallel to the fixture.

Anyway the point of the project was to try and figure out how LEDs go together.

I don't need anything close to a 400w sodium replacement so I'm hoping that I don't need active cooling, even the LED street lights here don't have active cooling.

What I don't seem to find is any sort of measurements online for heat dissipation, most of the LEDs I've been looking at have a max and optimal temp rating. I get that lots of other variables like ambient temp and air flow etc come into play but I had been hoping there would be some sort of conversion like how heat sinks for SSRs come labeled by how many amps are going through the relay.

Another thing I don't understand is the choice between 1 led and multiple leds. All of these 1 piece led floodlights that have been showing up everywhere seem to have 1 big led but then the aforementioned streetlights (which I got a chance to take a look at) are 84 x 2.3w. What drives that choice, how does that affect space and heat ?

And the other thing, standard led vs COB? From what I understand with the COBs you don't need a driver, just a transformer+rectifier. Why is that better (they cost more)?

 

Most LED I have seen do not have active cooling, the fixtures themselves are the heatsink being made out of aluminum and cool passively. The one picture I posted was the first one that had a fan on it, and it was a retrofit.

That is basicly what a driver is. The driver is built into them just like the basic LED light bulbs you can buy for inside the home.