DiY LED - Cree CXA3070

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tr909

Member
Could you please guys tell me which reflector could fit on this holder? ( attached)
Also would like to know which type of reflector: flood , spot , medium.. :)

thanks in advance!
 

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ttystikk

ttystikk

Well-Known Member
tr909 said:
Could you please guys tell me which reflector could fit on this holder? ( attached)
Also would like to know which type of reflector: flood , spot , medium.. :)

thanks in advance!
Click to expand...
You want lenses, not reflectors. Get 110° spread.
 
ttystikk

ttystikk

Well-Known Member
MeGaKiLlErMaN said:
Was there a par difference with lens/reflectors? Or just a spread..I know there's a 10% loss with reflectors.. Not sure on the lens.
Click to expand...
There's a bit of loss with both, but lenses do a better job of getting photons on the canopy where they'll do you some good.

Lenses also have the advantage of protecting the fragile chip from damage or contamination, such as from overspray.
 
A

ab30g

Member
Just wanted to make several points about cooling:
This is part theoretical, since I haven't received my parts yet, and part practical. I used to overclock CPUs, so I have familiarity with cooling hot chips.

Heatsink thermal compound
They're pretty much all the same. Just use something. Dansdata did a review and compared:
  • several fancy heatsink goops (Arctic Silver varieties, Coolermaster, nanotherm, blah blah)
  • silicone grease
  • toothpaste
  • Vegemite
  • No compound
Using no compound at all performed poorly. The rest performed similarly. Toothpaste did (slightly) better than that $9 2mL syringe of Arctic Unicorn Dust. I don't recommend using toothpaste, it may dry out, but the point is, buy the cheapest stuff that won't dry out/smoke. Your object is to replace the solid-air-solid interface with a solid-liquid-solid interface, which transfers heat better.

Use something instead of nothing, but don't spend too much on that something.

CPU coolers
Cooling device efficiency is usually measured in degrees Celsius / Watt, ie: what temperature increase you can expect per watt of heat dissipated. Lower scores are better.
Dansdata has compared a bunch of CPU coolers
Basic observations:
  1. The 1 passive CPU cooler measured had an efficiency of 2.67C/watt (If you need to dissipate 50watts, you're going to boil water)
  2. Almost all active CPU coolers (with fans) were .5C/w - .8C/w (Good enough for most LED needs)
  3. When it comes to heatsinks, the bigger the better. Fancier designs with crooked fins, or sideways-fans, or fans-inside-heatsink (Orbs) instead of fans-on-top-of-heatsinks generally perform worse.
  4. Stock Intel coolers performed quite well (so break apart an old computer and use that fan/heatsink)
  5. More powerful fans is a big predictor of increased cooling efficiency, so be careful about undervolting too much
  6. Chipset coolers are crap.
The Alpine Plus CPU Cooler recommended here is a good choice based on the above observations.

LED Cooling for the cheap and patient
Since it will be a while before I start this project and I'm not in US, I'm ordering from Ebay/Asia with free shipping. I'll be using:
Cooler Master Intel P4 Socket 478CPU Cooler for US$5.xx each (Ebay# 381768728770) and 30mL of heatsink goop for US$1.xx (Ebay# 262872164780)
 
frica

frica

Well-Known Member
ab30g said:
Just wanted to make several points about cooling:
This is part theoretical, since I haven't received my parts yet, and part practical. I used to overclock CPUs, so I have familiarity with cooling hot chips.

Heatsink thermal compound
They're pretty much all the same. Just use something. Dansdata did a review and compared:
  • several fancy heatsink goops (Arctic Silver varieties, Coolermaster, nanotherm, blah blah)
  • silicone grease
  • toothpaste
  • Vegemite
  • No compound
Using no compound at all performed poorly. The rest performed similarly. Toothpaste did (slightly) better than that $9 2mL syringe of Arctic Unicorn Dust. I don't recommend using toothpaste, it may dry out, but the point is, buy the cheapest stuff that won't dry out/smoke. Your object is to replace the solid-air-solid interface with a solid-liquid-solid interface, which transfers heat better.

Use something instead of nothing, but don't spend too much on that something.

CPU coolers
Cooling device efficiency is usually measured in degrees Celsius / Watt, ie: what temperature increase you can expect per watt of heat dissipated. Lower scores are better.
Dansdata has compared a bunch of CPU coolers
Basic observations:
  1. The 1 passive CPU cooler measured had an efficiency of 2.67C/watt (If you need to dissipate 50watts, you're going to boil water)
  2. Almost all active CPU coolers (with fans) were .5C/w - .8C/w (Good enough for most LED needs)
  3. When it comes to heatsinks, the bigger the better. Fancier designs with crooked fins, or sideways-fans, or fans-inside-heatsink (Orbs) instead of fans-on-top-of-heatsinks generally perform worse.
  4. Stock Intel coolers performed quite well (so break apart an old computer and use that fan/heatsink)
  5. More powerful fans is a big predictor of increased cooling efficiency, so be careful about undervolting too much
  6. Chipset coolers are crap.
The Alpine Plus CPU Cooler recommended here is a good choice based on the above observations.

LED Cooling for the cheap and patient
Since it will be a while before I start this project and I'm not in US, I'm ordering from Ebay/Asia with free shipping. I'll be using:
Cooler Master Intel P4 Socket 478CPU Cooler for US$5.xx each (Ebay# 381768728770) and 30mL of heatsink goop for US$1.xx (Ebay# 262872164780)
Click to expand...
Also you don't need to spread the paste, pressure will spread it enough.

Spread, line, dot. Doesn't matter.
x-shape had the best coverage with least air bubbles, but it didn't matter for temps.

The results are pretty much within margin of error.

https://www.pugetsystems.com/labs/articles/Thermal-Paste-Application-Techniques-170/
 
T

ThaiBaby1

Well-Known Member
ab30g said:
Just wanted to make several points about cooling:
This is part theoretical, since I haven't received my parts yet, and part practical. I used to overclock CPUs, so I have familiarity with cooling hot chips.

Heatsink thermal compound
They're pretty much all the same. Just use something. Dansdata did a review and compared:
  • several fancy heatsink goops (Arctic Silver varieties, Coolermaster, nanotherm, blah blah)
  • silicone grease
  • toothpaste
  • Vegemite
  • No compound
Using no compound at all performed poorly. The rest performed similarly. Toothpaste did (slightly) better than that $9 2mL syringe of Arctic Unicorn Dust. I don't recommend using toothpaste, it may dry out, but the point is, buy the cheapest stuff that won't dry out/smoke. Your object is to replace the solid-air-solid interface with a solid-liquid-solid interface, which transfers heat better.

Use something instead of nothing, but don't spend too much on that something.

CPU coolers
Cooling device efficiency is usually measured in degrees Celsius / Watt, ie: what temperature increase you can expect per watt of heat dissipated. Lower scores are better.
Dansdata has compared a bunch of CPU coolers
Basic observations:
  1. The 1 passive CPU cooler measured had an efficiency of 2.67C/watt (If you need to dissipate 50watts, you're going to boil water)
  2. Almost all active CPU coolers (with fans) were .5C/w - .8C/w (Good enough for most LED needs)
  3. When it comes to heatsinks, the bigger the better. Fancier designs with crooked fins, or sideways-fans, or fans-inside-heatsink (Orbs) instead of fans-on-top-of-heatsinks generally perform worse.
  4. Stock Intel coolers performed quite well (so break apart an old computer and use that fan/heatsink)
  5. More powerful fans is a big predictor of increased cooling efficiency, so be careful about undervolting too much
  6. Chipset coolers are crap.
The Alpine Plus CPU Cooler recommended here is a good choice based on the above observations.

LED Cooling for the cheap and patient
Since it will be a while before I start this project and I'm not in US, I'm ordering from Ebay/Asia with free shipping. I'll be using:
Cooler Master Intel P4 Socket 478CPU Cooler for US$5.xx each (Ebay# 381768728770) and 30mL of heatsink goop for US$1.xx (Ebay# 262872164780)
Click to expand...
I remembered reading about the toothpaste, I agree, you need some type of heat paste, I think the brake stuff would work well and fairly cheap.
 
A

ab30g

Member
As I've been acquiring equipment lately, check out the local classifieds. Many people selling old CPUs for a few buck with the old heatsink fan for $5. Older CPUs ran quite hot, so the heatsink/fans were well designed.
 
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TheHero

Member
Could someone write down thrusty sites for buyng cree products. Which seller on alibaba? Do they know what they are selling?
 
Rocket Soul

Rocket Soul

Well-Known Member
TheHero said:
Could someone write down thrusty sites for buyng cree products. Which seller on alibaba? Do they know what they are selling?
Click to expand...
Try Kingbrite for alibaba, or @CobKits here on Riu. Do your research though, cree is definently not the top chip anymore for rhe price people are asking for it. Bridgelux, citizen and lumious is one generation before cree by now.
 
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