Looking nice koondense. Dion i have a question i just received my arctic 11 plus heatsink/fans, and it has a part on the heatsink face that is raised. Looks like the pictures you posted on pg 20, i also have ideal holders on the way, but i think they are going to hang over the sides of the raised section of the heatsinks. The raised heatsink face measures 2"x 1 3/4" while the ideal chiplock cobholder has a 1.97" or 50mm diameter. Am i going to have to rethink my gameplan? The screwholes and chips should work just worried about the overhang of the holder mostly i guess.
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LED FAQ) Building and DIY
- Thread starter Dion
- Start date
Dion
Active member
dont worry bout it
as long as the cob is on the sink u r golden
play around until u get the whole back of cob onto sink mark and drill
BuddyColas
New member
Need some help. I have been inspired by this thread and have ordered all my parts save the Ideal cob holders. A good source for the Ideal holder would be appreciated. Thanks
BuddyColas
New member
REALSTYLES
Member
Arrow.com has the lowest price of $2.42 usd
BuddyColas
New member
Thanks for the tip. I have wanted a good LED for quite a while, but have not found a factory one to give uniform coverage of a 2x4 foot space…until reading the DIY LED threads on the forums lately and getting acquainted with the Cree cobs. I ultimately made the leap and went with the CXA2530s at 3K and 80cri. I got 10 of them at a good price. I know I am not at the forefront of technology, but 5 each on 2 40” x 4.85” heatsinks should make for a uniform PAR print for the girls.
Dion
Active member
BuddyColas
New member
First thanks for making this thread. I have read and re-read it trying to learn the basics. I spent some quality time with the Product Characterization Tool…very instructional. And finally I am getting the relationship between binning vs current vs lumens vs lumens/watt. I ultimately went with the CXA2530s because they were the best lumens/dollar…particularly because this is my first try at a DIY LED project.
And to your question, I will start at a modest 700ma and see with my IR meter how the heatsink responds (this is all new to me). I am going to try and go passive if the temps are low enough. I will be using 2 Mean Well ELG-150-C1050A for drivers, so I can drive them from 525ma to 1050ma. I figure with a T2 bin and 45C (assumption), that current range would give me around 2400 to 4200 lumens per light (correct me if you see the chart different). I am hoping in that range the girls will respond well!
So assuming 37v at the LEDs and 525ma to 1050ma to the LEDs, that would make the combined power of the 2 light bars about 200 to 400 watts. I am thinking I will need fans if I try and push it.
Also, I have a modest Lux/Lumen meter that does not measure PAR but it is an excellent tool for measuring the uniformity of a light foot print. I really think with 10 points of light it will blanket my 2x4 area well. All the parts are in the mail, but when I get it built and running, I can include some actual measurements and pics.
Dion
Active member
true dat! the 2530 is a a great choice(lowest $ per lumen) for that reason especially if u are in the states and can easily get the meanwells(total cost is very nice)
Im glad the thread helped u i wanted it to help ppl understand how to desighn a light for thier own needs rather than just offer a couple or the "best" options
yea in a 2x4 that will be killer( overkil even) I would have prolly gone for the 700mA version because @ 1050mA that is over 10k lumens per sq foot!!!! and only 110L/w assuming u can passively cool those(42w each to 45c)
I look forward to ur temp tests(what sink u using?) because i think u will find at about 750mA temps will be way more managable and still u will be getting 8000 L/sq ft @120L/w
@650mA u are getting 7000L/sq ft and 125L/w
I know you know this and have looked at the pct, the point i am trying to highlight is that its in ur best interest to keep these cool
a cooler chip at lower current can achive better/= total photon output than a hotter chip @ higher current AND will be more efficient
so driving them harder wont always give more light
as u can see the temp on the right is 70c( ive had temps go up to 79c before i eventually cooked the chips)
if the heatsink reaches its max thermal capacity there is no point running the chips higher
we see here if a heatsink can handle only 20w(whcih u would have to check and see) then driving the chip higher will not increase light output-infact light out put will continue to decrease(as will efficiency) as we increase current until we reach around 625mA then it will be the same while consuming about 9% more power-unfortunately i cant be fuct running this analysis for increase in temp as the current increases but i hope you get the idea
here is another chart to illustrate the point
anyway do the tests(plz share i love info) and then u could add a teeny tiny ram card fan (.smth watts) per bar and see a huge dif in temps
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morgandecaptain
Active member
BuddyColas
New member
true dat! the 2530 is a a great choice(lowest $ per lumen) for that reason especially if u are in the states and can easily get the meanwells(total cost is very nice)
Im glad the thread helped u i wanted it to help ppl understand how to desighn a light for thier own needs rather than just offer a couple or the "best" options
yea in a 2x4 that will be killer( overkil even) I would have prolly gone for the 700mA version because @ 1050mA that is over 10k lumens per sq foot!!!! and only 110L/w assuming u can passively cool those(42w each to 45c)
I look forward to ur temp tests(what sink u using?) because i think u will find at about 750mA temps will be way more managable and still u will be getting 8000 L/sq ft @120L/w
@650mA u are getting 7000L/sq ft and 125L/w
I know you know this and have looked at the pct, the point i am trying to highlight is that its in ur best interest to keep these cool
a cooler chip at lower current can achive better/= total photon output than a hotter chip @ higher current AND will be more efficient
so driving them harder wont always give more light
View Image
as u can see the temp on the right is 70c( ive had temps go up to 79c before i eventually cooked the chips)
if the heatsink reaches its max thermal capacity there is no point running the chips higher
we see here if a heatsink can handle only 20w(whcih u would have to check and see) then driving the chip higher will not increase light output-infact light out put will continue to decrease(as will efficiency) as we increase current until we reach around 625mA then it will be the same while consuming about 9% more power-unfortunately i cant be fuct running this analysis for increase in temp as the current increases but i hope you get the idea
here is another chart to illustrate the point
View Image
anyway do the tests(plz share i love info) and then u could add a teeny tiny ram card fan (.smth watts) per bar and see a huge dif in temps
Thanks for the prompt feedback. I am so looking forward to getting those light bars up and running and checking the current vs heatsink temps. The heatsinks are from heatsinkusa.com. It is 4.850” wide at goes for $0.98/foot.
And having built some of these, how close would you go with the end LED to the end of the heatsink? And inch? Two inches?
I was thinking about using some Nichia serie 60 with similar data but much lower price, at least for us living in Europe.
http://www.leds.de/en/High-Power-LE...EDs/Nichia-Chip-on-Board-Modul-Series-60.html
How do you people think about that,it´s half the price for the led´s.
Rilla.
http://www.leds.de/en/High-Power-LE...EDs/Nichia-Chip-on-Board-Modul-Series-60.html
How do you people think about that,it´s half the price for the led´s.
Rilla.
BuddyColas
New member
Nice looking photon generator you got there! A few questions for the led noobs. Where did you find the figure 63% efficient? Or if it is a calculation, please share how you did that...inquiring minds want to know. Also, if I read the charts right, each LED puts out about 9200 lumens at 800ma. Is that what you figure? Lastly, a few more mechanical shots on the top side on how you built it would be good (hint).
Dion
Active member
hey Rilla, I actually wanted to ask you about that site
they dont seem to list the binning they sell-only top binning of the model
ie that cob is listed as NFCWL060B sm503/G2450,G2650/R8000
so unclear which bin you actally get?
a few of the cree chips i was looking at dont even list possible binnings....
am I missing smth?
Dion
Active member
doesnt really matter for active cooling
for passive prob about 5cm
but i advise u to desighn the spacing around canopy uniformity then worry bout temps once u check them
FYI that heatsink is sold per inch not foot
98 cents per inch
the thermal capacity is listed as C/W/3": approximately 2.25
which as i understand means it can handle about .75w per inch(which doesnt seem right by looking at it[far too low] althoug converting those antiquated measurements into smth useful does confuse me)
perhaps others can help
anyway based on that and assuming you will drive thses 2530s @ 25w(power consumption not heat output which would need to be calculated based off efficiency which i dont bother with because no one ever regretted keeping leds too cold) you would need
10 inches per cob
that however sounds way off i must be missunderstanding the " C/W/3": approximately 2.25 "
other please chime in
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Yes i´m also not sure about that, i will have to ask them when i decide to buy( or if i will buy )
Same with many other sellers i think, not much info about bin.
Rilla.
