100W LED Unit... Anyone Know Much About These?

This is a very harsh white light. I prefer 4000 Kelvins because it is a warm light.

Most of these come from China and have a low quality. I have ordered a few LED bulbs and the ratings are optimistic and the consistency is poor.

I would buy with caution knowing that you may not get what you expect nor hope for.

check out LED street lights for an application of high output LED's.

yeah, thanks for the input.

I am more or less considering buying 1w or 3w LED's in bulk to make up either 50w or 100w units, as I too am dubious on the quality (hence my post asking for experience of same) of construction regarding shorts etc. of these one piece units.

Colour temperature is not really a problem, as am considering using a combination of warm and cool white LED's at determined current proportions to give about 5400k

I have seen LED's "like" the one pictured and was impressed with the intensity of the output .. nicely dimable too..

I've seen a lot of led's

I suggest you look at www.ledsmagazine.com

They have archives and all manner of reports and ads that will help you in this.

Heat is the enemy, and if the heat path for the waste heat is not good enough then the LED dice will run too hot and dopant diffusion will soon reduce their light output.

With proper heat sinking they can easily achieve 100,000 hours.

Many of the low cost chinese units have bad thermal design.

With properly designed LED units you would not need a socket, after all, a socket is to replace it, and a properly designed LED lamp could last 1000 years. (the heat sinking would be good enough that the die temperatures would never go beyond the safe infinite operating area, most design for 100,000 hours at 50% loss = failure point by brightness)

These were designed for recessed luminaries (can lights) What is missing is the AC to Dc rectifier unit (the driver.) Heat is eliminated through the housing of light fixture, metal mounting plate (comes with it) and air flow. Great little units. I know a designer of LED lights in America. You must design a light fixture and provide the driver to make it work.

they can be ruined easily if the power conditioning to the unit is not good and the proper dissipation of heat is not achieved.

Thanks for your input. I agree about need for proper driver and heat removal. Input so far has been encouraging. Guess I will have to purchase a few and test them out.

I have been working on this subject for the last few months. In my organization we wish to go for LED based lighting system in a big way. It effects energy savings to the tune of 60-70%. LED lighting is considered to be the latest in lighting technology with a very bright future. We are proceeding in phases. Firstly we are going for streetlighting projects where potential for energy savings is considered to be quite high. Though a lot of research is going to reduce the cost (it is 5- 10 times costlier than conventional lighting) and increase the lumens/ watt, a good number of manufacturers are in the market offering street lighting and office lighting LED solutions. In US it is going in a big way. I am sure colleagues on this forum from US must be aware of it. For example, US Department of Energy is coordinating the research effort and the latest developments in this field of lighting technology.

Over these few months of studies, I have the following things to share with you:

a) LED source is the most important part of the LED luminaire. Manufacturers like Philips Lumileds, Cree Inc, Seoul Semiconductors, Nichia, Osram etc. are some of the reputed manufacturers of LEDs. It is LED source which determines the quality and quantity of light and its capability of producing lumens per watt. LED source of 1-1.2 w is categorised as High Power LED.

b) Thermal mangement of the LED luminaire is the most critical aspect of LED luminaire design and will ultimately determine the life of the luminaire, and reliability of the lighting source. It is a major challenge to the designer. To keep the pn junction temperature as low as possible. LED luminaire life is claimed to be 50,000 hours at 70% lumen depreciation.

c) Third important thing is the driver unit which is made integral with the luminaire.

d) The pay back period is huge that is why it has not picked up in the market. However, if LED lights are purchased in a large quanitity, the payback period does come down.

e) There are number of standards to which the LEDs are manufactured. The main ones are IES LM-79 (Luminous efficiency) and LM-80 (Lumen Maintenance).

I am enclosing a link which shall privide you more insight into the subject. There are more on the internet which can be accessed through google search:

http://www.cormusa.org/uploads/CORM_2009_-_IESNA_Standards_on_LED_and_SSL_LM79LM80_and_Future_Standards_CORM_2009_Y

BB Raina

Raina, regarding your answering, i have two comments:

1. since this year LED developed, the flux effiency is becoming better. However, it is still an important to reduce the thermal for the LED source. JSD200 can help you to make a good LED design: it can measure the photo & color parameter VS thermal & electricity, this system is applicated by Philips, GE lighting and OSRAM, you can learn more at: http://www.lisungroup.com/product-id-222.html

2. Many LED luminaires design engineer often asked this question: how to design a luminaires which have a good distribution curve and high effiency? There is many light design software such as Dialux, the engineer can use it to design the RIGHT luminaire under IES files. The questions is to get the standard IES file, LSG-1800 is a IEC recommend goniophotometer, it can export IES file. LSG-1800 can measure the following parameters: Electronic parameters, spatial intensity distribution curve, spatial iso-intensity curve, iso-illuminance distribution curve, luminance limitation curve, luminaire efficiency, glare grade, effective beam angle, upward luminous flux ratio, downward luminous flux ratio, total luminous flux, effective luminous flux, utilization factor. I have add a link for the Goniophotometer: http://www.lisungroup.com/product-id-241.html