Start By Determining How Much Light You Need
The number and type of LEDs you select for your application depends on many factors, including:
- The size of the area to be illuminated
- The illuminance (brightness) that you need
- The light color that you need
Total lumens required is estimated by selecting a similar light source from the table below and multiply the value in the Lumens per Watt (LPW) column by the total wattage of your current lighting.
For example, if you are using two 12" fluorescent lamps rated at 8 watts each with a lumens output of 60 LPW, then you will need select LEDs that can generate 960 lumens to produce the same amount of light.
| Light Type |
LPW
|
|---|---|
| Incandescent Bulb |
12 - 18
|
| Halogen |
20
|
| Fluorescent Tubes |
50 - 100
|
| Metal Halide Lamp |
65 - 115
|
| High-Pressure Sodium Lamp |
85 - 150
|
| Low-Pressure Sodium Lamp |
100 - 200
|
LED Type Selection
We recommend that you use our 20mm Star LED modules whenever possible. These modules are not only easy to work with, but are much easier to cool than multiple LED modules. We also offer a wide variety of secondary optics for the Star LED modules.
If space is at a premium, then our single 10mm square LEDs is a good option.
Lens Selection
The output from an LED typically has a beam angle of about 120 degrees, which is usually too wide for most applications. To focus the light output, you need to mount a secondary optic in front of the LED.
You will need to do some experimenting to determine what beam angle will work best for your application.
Powering The LEDs
Unlike incandescent or fluorescent bulbs, high brightness LEDs require a current regulated power source or driver. You can learn more about drivers here.
For long life, color stability and low heat generation, you should limit the drive current to 700mA or less whenever possible. Even though most Rebel LEDs are rated to operate as high as 1000mA, running LEDs at these power levels requires careful design of the cooling system.
We offer a wide variety of 700mA power drivers to choose from. Which one you should use will depend on your specific requirements. As a starting point, you may want to check out the 3023-D-E-700 driver. This DC driver is dimmable and comes with an integrated wiring harness - making it easy to connect the driver to your power supply and dimming potentiometer.
Depending on the input voltage that you have available and the LEDs that you are powering, a single BuckPuck driver can power up to 7 series connected Rebel LEDs at 700mA. You will find more details about using BuckPuck drivers, including some electrical schematics in the driver documentation.
In addition to the LED driver, you will also need a DC power supply. Most folks use a standard DC wall adapter. The power from the wall adapter goes directly into the LED driver, which in turn regulates the output current to the LED(s).
Cooling
Quite a bit of heat is produced inside an LED that must be dissipated, making heat management an essential part of your design consideration. You cannot operate high power LEDs without providing some means of cooling the LED.
Cooling is usually achieved by mounting the LED directly to a finned aluminum heat sink, and in the case of confined environments, using one or more cooling fans to extract the heat from the enclosure. You will find a detailed article here that provides more details about how to cool high power LEDs.
Mounting
LEDs are usually mounted directly to a finned heat sink. The two options that we recommend are double-sided thermally conductive tape and thermally conductive epoxy.
- We do not recommend using mechanical fasteners for any LED modules that we offer.
LEDs are not waterproof or moisture resistant, so if you are using the LEDs in an outdoor or damp location, you will need to mount the module inside a moisture resistant enclosure.