Fortitude7695
Active Member
I've been lurking around for quite a while, reading a ton. I wanted to show my idea for a Cob LED build and get some feedback, particularly as it relates to thermal management (i.e. lowest cost passive heatsink options) although all manner of criticism is welcome.
The parameters for this project are to build a DIY cob based led fixture for use in a 3' x 3' space with an eye toward overall build cost efficiency, power consumption vs. performance efficiency, and a few extra features like some degree of spectrum control.
I've always sort of gravitated toward Bridgelux. I like their bang-for-the-buck proposition. Maybe I'm a cheapass. I'm aware of Cree. I'm largely ignorant of Citizen and need to do some more homework on them. Maybe I've just gotten used to reading the Bridgelux tech sheets. In any event, I'm looking at working with the Bridgelux V22 chips as they are hella cheap at like $13 each.
My plan is to use:
12 Bridgelux V22, 3K, 90 CRI, C Bin (BXRE-30G6500-C-xx) and
6 Bridgelux v22, 4k, 80 CRI, C Bin (BXRE-40E6500-C-xx)
I was planning on driving the 12, 3k, 90 CRI's in parallel with a Meanwell HLG-480h-54B, which should be like 742ma (ish) drive current. I was planning on driving the 6, 4k, 80 CRI's in series with a Meanwell HLG-240h-C700B. I want the B versions for dimming capability so I can adjust relative color balance based on the color temp of the cobs.
According to the Bridgelux Product Simulator spreadsheet available from Bridgelux this should produce the following at full drive current at 25 degrees C:
12 BXRE-30G6500-C-xx @ 742ma X 92.3 ppf = 1107.6 ppf at 2.5 umol/J
6 BXRE-40E6500-C-xx @ 700ma X 93 ppf = 558 ppf at 2.7 umol/J
For a total of 1665.6 ppf / .836 (the fraction of a square meter that a 3 X 3 represents = 1992.34 pppfd running a full power.
Of course I'm not planning on running Co2 or ever really running them that hard. I expect running them at less than half of that usually which of course increases efficiency further:
12 BXRE-30G6500-C-xx @ 371ma X 49.8 ppf = 597.6 ppf at 3.0 umol/J
6 BXRE-40E6500-C-xx @ 700ma X 93 ppf = 322.2 ppf at 3.2 umol/J
For a total of 919.8 ppf / .836 = 1100 pppfd at an average 3.06 umol/J
I'd really like to use passive pin fin heatsinks for cooling but they'd need to be cheap in keeping with design concept of this build. I don't yet understand watts vs. heat watts well enough to know what I could get away with. I want heat sinks a little overspecced of the maximum drive power of 40 watts (rounding up a bit). Active cooling is of course an option but I really like the fail safe simplicity of passive cooling especially since I'm planning on wiring 2/3 of the cobs in parallel.
Anyway I have a ton more thoughts on this build but I thought I'd start with this and gauge reaction in case I'm way off in my thinking somewhere.
The parameters for this project are to build a DIY cob based led fixture for use in a 3' x 3' space with an eye toward overall build cost efficiency, power consumption vs. performance efficiency, and a few extra features like some degree of spectrum control.
I've always sort of gravitated toward Bridgelux. I like their bang-for-the-buck proposition. Maybe I'm a cheapass. I'm aware of Cree. I'm largely ignorant of Citizen and need to do some more homework on them. Maybe I've just gotten used to reading the Bridgelux tech sheets. In any event, I'm looking at working with the Bridgelux V22 chips as they are hella cheap at like $13 each.
My plan is to use:
12 Bridgelux V22, 3K, 90 CRI, C Bin (BXRE-30G6500-C-xx) and
6 Bridgelux v22, 4k, 80 CRI, C Bin (BXRE-40E6500-C-xx)
I was planning on driving the 12, 3k, 90 CRI's in parallel with a Meanwell HLG-480h-54B, which should be like 742ma (ish) drive current. I was planning on driving the 6, 4k, 80 CRI's in series with a Meanwell HLG-240h-C700B. I want the B versions for dimming capability so I can adjust relative color balance based on the color temp of the cobs.
According to the Bridgelux Product Simulator spreadsheet available from Bridgelux this should produce the following at full drive current at 25 degrees C:
12 BXRE-30G6500-C-xx @ 742ma X 92.3 ppf = 1107.6 ppf at 2.5 umol/J
6 BXRE-40E6500-C-xx @ 700ma X 93 ppf = 558 ppf at 2.7 umol/J
For a total of 1665.6 ppf / .836 (the fraction of a square meter that a 3 X 3 represents = 1992.34 pppfd running a full power.
Of course I'm not planning on running Co2 or ever really running them that hard. I expect running them at less than half of that usually which of course increases efficiency further:
12 BXRE-30G6500-C-xx @ 371ma X 49.8 ppf = 597.6 ppf at 3.0 umol/J
6 BXRE-40E6500-C-xx @ 700ma X 93 ppf = 322.2 ppf at 3.2 umol/J
For a total of 919.8 ppf / .836 = 1100 pppfd at an average 3.06 umol/J
I'd really like to use passive pin fin heatsinks for cooling but they'd need to be cheap in keeping with design concept of this build. I don't yet understand watts vs. heat watts well enough to know what I could get away with. I want heat sinks a little overspecced of the maximum drive power of 40 watts (rounding up a bit). Active cooling is of course an option but I really like the fail safe simplicity of passive cooling especially since I'm planning on wiring 2/3 of the cobs in parallel.
Anyway I have a ton more thoughts on this build but I thought I'd start with this and gauge reaction in case I'm way off in my thinking somewhere.
