DIY LEDs - The write-up

[FW fugitive]

I would think that unless there is a VERY good reason regarding the quality of light, the running efficiency alone makes it clear that Cree LEDs are the right choice. What do the 10w Bridgelux lights get, 50 or 60 lumens/watt? That seems to be the average efficiency of these misc brand high output LEDs. This means latest generation of Cree LEDs consumes half the electricity to make the same amount of light, and the next generation of Crees which is due this summer approaches an efficiency which would mean they are consuming 1/3 the electricity to produce the same amount of light...

My thoughts too. I wondering if there was something I was missing, and thought I'd give Mr. Blasterman a chance to come back and politely explain his experience with these.

Although the Bridgelux are more efficient than you state, and the price seems pretty good... the 5W puts out 450 lumens, the "40W" (actually more like 50W) puts out 5000 lumens (edit - looked at the data sheet - 4500 lm under reasonable junction temperature). The pricing is pretty competitive with the Cree. With good optics, it would make a hellofa spot.

There's still the issues of colors and optics, tho.

The other LED's that were mentioned are pretty horrid. "Satistroncs", they appear to be all the rage on ebay right now. The 100W puts out 6000-7000 lumens. Costs as much as the Bridgelux, consumes twice as much power, puts out the same amount of light. If I want that, I'll get another tank heater. :lmao: But you can get it in blue & other colors.

Personally I think these monstrosities will be fun when they come out with mixed dies - kind of like RGBW, except with added UV/violet (400 nm) and 660 nm, maybe amber & cyan too. Then make them individually addressable so you can vary to almost color with a realistic CRI (hey, there's a reason for dimming!).

 

[TheFishMan65]

Well I order my royal blues and lenses last night, not so exiting for you I know. ETG currently has D3-16 bin in stock (unless I ordered the last of them). If I am reading the data sheet correctly these are the lowest (450-455) for wavelength (maybe not what you want) and brightest for bin (we all like them bright though). Maybe that information might be a little more interesting.

 

[Jay1982]

I have 6 meanwells, could I hook them up to one extension cord going to the wall?

 

[The Grim Reefer]

Grim; About your sink temp: The hard part about, "Is it cool enough?", is that any valid comments have to assume that the interface between the star and the sink is a good one.

This means:
1) A nice flat surface on the sink.
2) Very little thermal compound.
3) Reasonably high mounting pressure.
4) Reasonably uniform mounting pressure. In some cases two tightened screws might mean the star goes into a potato chip shape which would be bad.

Of course, with interface issues, a really nice and cool heat sink could always mean smoking hot LEDs that are about to catch fire because they can't effectively pass their heat away to the sink.

The fact of the matter is - if you were to keep a HPLED mounted on a 1 sqin star in air cooler than 130F you could run 350mA thru it for at least 10 years of service with no heatsink. So, keeping the heatsink below 150F is more than adequate for over ten years of service. And that is a LOT hotter than you can touch.

As a side note it's been found that the biggest factor in the reduction of light output over time is a function of the air temperature of the air the LEDs are in. That's the air in front of the LED. Any cooling scheme would do well to make sure that air is kept as cool as possible.

Thanks. I used the thermal tape so I figure as long as the LED's aren't hanging by the wires we be good

I am going to do some better readings but I think the surface of the stars were about 5 degrees hotter than the heat sink so the transfer seems to be pretty good. I also haven't done the tests with the acrylic shields over the channels yet but at 2x1 inches I don't suspect that will cause much of an issue.

 

[seaheard]

Need some assistance. Can anyone shed some light on the process of attaching a CREE LED to a star mount? I might have access to CREE LED's, but they are not star mounted, just the bulb itself. Thanks.

 

[CJO]

I have 6 meanwells, could I hook them up to one extension cord going to the wall?

Which model?

CJ

 

[HeneryH]

Need some assistance. Can anyone shed some light on the process of attaching a CREE LED to a star mount? I might have access to CREE LED's, but they are not star mounted, just the bulb itself. Thanks.

I believe wave soldering is the only way. You will be VERY hard-pressed (perhaps impossible) to do it with a soldering iron.

 

[Jay1982]

Which model?

CJ

Oops, sorry. Eln 60 48 p

 

[wfournier]

Need some assistance. Can anyone shed some light on the process of attaching a CREE LED to a star mount? I might have access to CREE LED's, but they are not star mounted, just the bulb itself. Thanks.

Google surface mount oven.

 

[joseney21]

hey guys,

I have 2 heatsinks with 30 leds each (a lot like soundwaves original design)... the whites and blues alternate except for the center row of six leds on each fixture which consists of only blues

looks like this

W B W B W B
B W B W B W
B B B B B B
B W B W B W
W B W B W B

I would like to dim the whites and blues separately and would also like to dim the center row separately.

can i do this with one wall wart? if i can do this with one wall wart how would i wire all the pots and meanwells?

i think i remember reading that pots between 5K and 200K are ok to use to dim. is this correct? if not what would be ok?

can i use only one power cord (or at least the least possible) going from my fixture to outlet?? how should i wire this up(if possible)?

pic would help a lot if possible
thanks

 

[TheFishMan65]

joseney,

First question what driver are are you using and how many?

 

[joseney21]

5 X meanwell eln 60 48d

 

[TheFishMan65]

I don't use meanwell's, but if I remember everything I read.
You need a 10 volt supply. Wire a 10k pot (ouside pins) to the ground and 10 volt lines. Wire the middle pin to 1 or more of the + Dim on the meanwells. Wire it - Dim of the meanwells to the ground of the 10 volt supply.

[EDIT]
See popper's post post number 139 and around there for some pictures and maybe a better explanation.

 

[kcress]

Grim I'm sure your setup will perform well.

TheFish; Yes optics probably aren't a LED's best friend.. I would just make sure you move air past them if you are using a protection shield. If you are doing a open High Mount,(Widmer), so there is no front enclosure, you are probably just fine.

 

[TheFishMan65]

I am planning on going 2 feet and no shield, just wondering if there is any data out there.

 

[CJO]

Oops, sorry. Eln 60 48 p

They are rated at 62.5W each. So, if you have six of them, that would be a total of 375W, or a total of a little over 3A, so you would be fine running them off of one cord of suitable size.

CJ

 

[Jay1982]

Thanks CJ!

 

[kcress]

I am planning on going 2 feet and no shield, just wondering if there is any data out there.

Anymore data about what?

 

[TheFishMan65]

Sorry, just wondering if there is any solid data on LED life and lenses. I agree with you that lenses aren't LED's best friends. But are they enemies, acquaintances, or just friends.

 

[kcress]

acquaintances. The lifetimes are enormous. Don't sweat them. The issue is lumen maintenance. You won't want a still running LED 50 years from now because you may need a flashlight to find it. If the air around your LEDs is below 50C you have nothing to fear. But, for maximum lumen maintenance you would want 25C air around the LEDs.