Testing LED fixture.

Hello friends,

Here you will find attached some pics testing a 36 Watt LED lighting device made by me against a 84 Watt FL fixture, with no screen.






Hope you like it !

As you can see the amount of light is for the fluorescent. You can perceive it on the walls, but the lux reading on the floor was quite similar.



You can see over the ammo case a lux meter, with LED, Fluo and LED+FLuo
Javier

Cool!

Do you have any closeup pictures of the led fixture you made? Also specs on it or how you made it "what LEDs, drivers, etc."

Thank you, Jason.

In fact it is a little bit more industrial than a simple homemade lamp, as it is made with a custom alloy profile and a custom FPC (Flexible Printed Circuit).

The alloy profile is 2500 mm long 6061 Al, anodized unit, designed to be very rigid, as well as to dissipate the heat.

The FPC has 272 PLCC LEDs, 3528 type , 4200ºK, with 65 lm/watt efficiency (usually on this kind of LED is 50% of that), and LEDs are wired in series with small resistors to be feeded with 24V. At 24 V it shows 1,38 Amps, and as power supply I'm using a generic 60 Watt unit, IP67, but I'm having made my own.

Maybe 65 lm/watt doesn't sound too great, but the thing on this kind of fixtures with hundreds of emitters is the even distrobution of the light, creating less shadows, and the fact of the directional light, with no need for unefficient reflectors, makes the device competitive when compared to a fluorescent system.

Javier

PD. Will post pics.

I have a few questions for you.

Since power supplies are normally more efficient when the input voltage is closest to the output voltage, is there a reason you picked 24 volts verses 48 (or higher) to get as close to your 120 input voltage?

Also, did you consider looking into the high voltage LED's that would only require a rectifier and some caps verses a driver and power supply? If you did look at them and decided against them can I ask your reasoning?

Cool project though!

The OP is in Europe. I believe the nominal voltage is 230 VAC over there instead of North America's 120 VAC.

24 VDC is an industrial standard. It would be a lot easier to get parts already certified to various government standards than to design and certify your own at a different voltage.
In the US and Canada 24V and below are exempt from UL listing/CSA approval electrical requirements. Go above 24V and there is the need to get the said listing - an expensive and very onerous process. A lot easier to build to 24V and just buy an already UL listed/CSA approved 120-24V power supply.

LEDninja, great explanation, you saved me a lot of trying to explain this with my crappy english.

High voltage LEDs, on the other side, are usually COB, (Chip On Board) and this way it is not possible to spread the emitters as much as possible over the area to be lighted.

Using as much emitters as possible really makes a difference, as long as you can get uniformity of lux value on every point, creating less shadow areas, thus helping your visual system.

When I arrived home the light was working (with a regulable power source) at 16V and 0,167 Amps, arround 2,7 Watta, and the whole room needed no more light for me to navigate arround, as I was getting 10 lux on floor, which is 10 times what you get on a clear full moon night on tropics.

Javier

As promised, detail pics.




LED FPC and wiring.



Projection pattern.

Re: Testing LED fixture. More pics

More real world tests.

This time we are testing it on a parking. The first parking lot has a LED light bar (GUION type) which is pulling 20 Watt including the driver. The rest of the luminaires are a single 1200 mm 36 Watt fluo. (Real 42 Watt, including ballast).

The lux reading on the floor, under the fixture is 89 lux for the LED and 43 for the fluo.



Javier