LED specs? good/bad/okay?

[hlem]

I'm trying to get an LED to replace a 250W DE MH, but dont know too much about LEDs,

So can someone tell me if these specs are good for this fixture?

55x3-watt Epistar LEDS fixture; approx. 16 x 8.5 x 3 inches
3-watt LEDs driven to 2-watts
4200 lumens , 90° optics, comes in ~14k or 20k color
PAR tests using a new Apogee meter, fixture hung 6" above the water show 200+ PAR at 20"+ deep! And, 150+ PAR on the fringes of a 24"x24" light pattern.

any help would be appreciated

thanks

Ha

 

[bruce 1]

What brand are they?

 

[Troylee]

Iirc that's the fixture Luke "reeffiltration" carries... Check out his forum he has done a lot of testing and has numbers etc...hth

 

[gar732]

They sound like Luke's fixtures. He's a great guy to deal with and they've gotten great reviews from the people that have them. They also have the best warranty that I've seen. A buddy of mine has had a few of his older fixtures for over a year now and they're great. If you have specific questions I'm sure he'd be more than happy to help you out.

 

[hlem]

It's not luke's, different led configure, nemosled.com

 

[gar732]

They are one and the same, on the site it says it's a joint venture with reeffiltration.

 

[hlem]

oh didnt see it.

seems like a misprint in the lumen output. Nemo's 4200, Luke's 7200

 

[Hahnmeister]

A Ushio 250wattDE 10,000 or 14,000K bulb puts out about 10,600 lumens. I know its not the best figure since PAR would be better, but comparing the spectra of both sources suggests that the translation to PAR shouldn't be that far off when comparing spectra and output. I would say that you should be somewhere above 8000 lumens to claim having the same output as a 250 watter. If going for the more 20000K look, I would say something in the 5000 lumen range is about right. When I size up LED's, I usually end up with 10,000 lumens worth replacing a 250 watt halide... thats about 18 Cree XM-L's at 1500mA FWIW.

 

[wld1783]

According to our PAR measurements 36 Cree XP-E LEDs driven at 700mA or as Hahnmeister said 18 XM-Ls at 1500mA in the rough equivalent of a 250 watt MH. Many of the fixtures imported now all use the same housing but the circuit board is custom designed by the importer. For what its worth I prefer the Cree LEDs then the bridgelux LEDs. They offer the best efficiency and spectrum. I cant comment on the Epistar as we have not seen any fixtures over growing reef tanks.

FWIW when we did our PAR measurements we did them alongside a Lux Meter and found the relationship somewhat linear with the MH Bulbs and LEDs we were using.