DIY bridgelux LED fixture

[turbo21]

From what I've read the "Aquastyle" Bridgelux are only rated for 700 mah. I would be careful pushing them much more than the 2w the cheap drivers are putting out.

kinda confused here. They are 3 watt led's rated for 700ma. Why are they not rated at 2 watts and not 3? The cheap drivers are rated at 680ma +/- 5%

 

[ReefLEDLights]

kinda confused here. They are 3 watt led's rated for 700ma. Why are they not rated at 2 watts and not 3? The cheap drivers are rated at 680ma +/- 5%

Dont be confused by 3 watt. Look at it like a V8. Not V8s are the same, you have to look closer to determine which is best. Big difference between a 455 Rocket and a 289...

LEDs have a Forward Voltage Range and Max Current Rating.

LEDs rated for a Max of 1000mA are normally considered 3 Watt. If they have a Forward Voltage of 3-3.5v thats is were they get the 3 Watt Rating at their max drive current.

As a rule of thumb you want to drive your LEDs at satin or 66.6% of its max rating. Driving them at 2/3 or 700mA is what most factory fixtures do.

This said, most LEDs in this class are rated at 1/3 or 350mA as this is the sweet spot for strict performance optimization.

Here is an example

The Cree XPG R5 (5 watt LED) driven at 350mA produces 139 lm

The Cree XPE R3 (3 watt LED) driven at 350mA produces 122 lm

The BridgeLux Cool White (3 watt LED) Driven at 350mA produces around 80 lm (interpolation based on 700mA)

If you double the current to 700mA you will not get twice the light. As the LED heats up it produces less light and there is a point were you can get less light by driving the LEDs Close to MAX. Especially with a weak Heatsink. A Cree XP or XT LED will still be around 90% of its max efficiency at 700mA. After this their efficiency along with most other LEDS will drop quicker "than Bill Clinton's Pants in a Sorority House".

For 3 Watt LEDs any thing more than 2/3 or 700mA in not efficient and may impact lifespan.

Cheap Drivers are like a cheap car they drive but dont last. A quality driver will drive the LEDs the same but will offer dimmability and better reliability.

BTW I personally prefer to drive the XP-G between 700-1050mA when its rated for 1500mA Max.

Bill