sixstring2112
Well-Known Member
man those lenses the dawg posted look like they block a ton of lumens.so you guys dont worry about the heat being trapped right on top of the cob les ?
DIY Passive cooling with PIN Heatsinks SST120 and SST140
- Thread starter robincnn
- Start date
BOBBY_G
Well-Known Member
if you want to send me a lens i can
-calibrate current on a 3070 vs 3590 so they give off equal par at 12" with no optics
-then put the lens on both and do a quick par grid to see if they are putting down similar pattern and intensity with the different LES size
robincnn
Well-Known Member
Welcome to my thread. If you would have come here a few weeks back I may not have been happy.
I have found my peace. Its not your fault if someone else cannot respect confidentiality and leak ideas/plans of @Greengenes707 and myself...
Yes their spread data is for 23mm LES. They also mention it works for Vero 29 so 29mm LES.
Cree 3590 is 30mm and should work too. It does show up on their website. I have met the rep and they did not have any concerns with me using 3590
Not sure if Citizen 1825 larger LES would work.
https://www.rollitup.org/t/lens-and-reflector-optics-for-cob.893660/page-11#post-12689170
You are right the efficiency is lost as the LES approaches near the end of optics. I think there is enough margin so 3590 should work fine.
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robincnn
Well-Known Member
It is hard to find a compatible holder. Not sure if lens puts enough pressure to hold down the COB. Will check.
robincnn
Well-Known Member
The whole test with PAR meter is based on the assumption that bream pattern is same identical between both tests.
Different LES size changes pattern and invalidates the test. Only sphere can tell if light is lost due to larger LES.
They don't block. It works great.
It does not make my Vero 29 a 3590 but it gives a very even spread.
3 gallon pot tomato
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optzulu
Well-Known Member
hello I have a question about pin fin heatsinks.
Can I mount 2 cobs on 1 big pin fin ?
https://m.alibaba.com/product/60434900941/Cold-Forged-LED-Heatsink-with-Diameter/specifications.html
something like that and then putting 2 citizen cobs on it each cob+holder is 55mm in diameter. So I will have a 40mm space between the 2 chips.
The heatsink is 150mm in diameter and I want to put the chips at the corners of the cirkel. Each cob will produce 37.5watt for a total of 75watt. What you think ?
Can I mount 2 cobs on 1 big pin fin ?
https://m.alibaba.com/product/60434900941/Cold-Forged-LED-Heatsink-with-Diameter/specifications.html
something like that and then putting 2 citizen cobs on it each cob+holder is 55mm in diameter. So I will have a 40mm space between the 2 chips.
The heatsink is 150mm in diameter and I want to put the chips at the corners of the cirkel. Each cob will produce 37.5watt for a total of 75watt. What you think ?
optzulu
Well-Known Member
why not close to the corner ? Sorry never worked with this things before.
Why not run them seperate ? pretty hard to find a passive heatsink for 37.5watt for 5€ Ofc when you run them all alone you get better spread. But remember those are not cree chips and run lower the spread is going to be fine.
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The 3 in the middle are going to be seperated on a straight heatsink and the 8 others on pin fin.
Why not run them seperate ? pretty hard to find a passive heatsink for 37.5watt for 5€ Ofc when you run them all alone you get better spread. But remember those are not cree chips and run lower the spread is going to be fine.
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The 3 in the middle are going to be seperated on a straight heatsink and the 8 others on pin fin.
welight
Well-Known Member
BOBBY_G
Well-Known Member
Thanks but i meant robin's lenses!
Malocan
Well-Known Member
Hi Robin,
Thank you, for sharing the informations about the khatod optic. I was searching for a lens or refelctor with a wide beam angle for citizen clu058-1825. After checking khatod internet side, i saw they make the lens for CLU054.
CLU54 have the same size like CLU058, so the lens(PL1825SR) should work(i hope).
I found even a cob holder that should work under that lens, the cob holder is from bender-wirth (LED Holder 458 Typ K1).
In one week when i recieve the lens and holders, i will do some PAR tests. To see how the PAR footprint is with lens or without lens
robincnn
Well-Known Member
CLU58 . And it is rated 80V/150V. Are you getting the regular or HV option
For 3590
I have some of these 449 holder for 3590 coming in 2 weeks. It is custom high voltage design rated for 300V
Will try out the 458 too. With 150V cant use more than 2x 1825's in series
PL1825SR is the 90 Degree lens. I shared a chart here. I think its a great option for 3590. 1825 is slightly bigger but may still work. Need to test.
https://www.rollitup.org/t/lens-and-reflector-optics-for-cob.893660/page-11#post-12689170
Good luck with your testing. Looking forward to seeing what footprint yo get,
The optic is designed to press down the COB. So no holder may be needed. But they recommended to test it thoroughly.
soldered 3590. I attached PL1825SR on it and did not have any cob holder. Monitoring Tc. Will do a 100hr test.
3590 and 1825 may work without the COB holder when PL1825SR is used.
If it works with 1825 then this would be the first optic compatible with PL1825SR .... other than 100mm glass lens.
Paste can stick to silicone optic and makes a mess. thermal pads would be better if no COB holder is used.
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Malocan
Well-Known Member
i will order the regular version, makes not much sense for me to order the HV version. Like you allready said the HV version is only good for 2 COBS(clu058-1825) in series:/
I will use parallel driver for my light
Malocan
Well-Known Member
no not really
i called today early directly at bender-wirth germany, i wanted to order diretly from them.
He said: ok but MOQ is 100, and to order from them i need to have a business.
LED Holder 458 Typ K1 cost around 350 euro (100pcs), i asked for 100cm long cables and 1,0mm thick on the cob holders.
Airwalker16
Well-Known Member
I use the the "blue goop" style thermal material from Mouser. Works so well. But I'm glad you're in the process of testing. I'm thinking it will work just fine after 100hrs.
robincnn
Well-Known Member
@CoB_nUt @Abiqua
Reached out to graftech and asked them if graphite thermal pad on aluminum heatsink could cause galvanic corrosion.
They mentioned that there needs to be a electrolyte such as water to start galvanic corrosion. Even under high humidity the aluminum oxide layer formed on the aluminum surface is sufficient to protect the pure aluminum below.
Looks like graphite thermal pads are fine for use on Cobs.
I would avoid sanding before installing cob. Sanding the heatsink would remove the aluminum oxide layer and may cause an issue.
Reached out to graftech and asked them if graphite thermal pad on aluminum heatsink could cause galvanic corrosion.
They mentioned that there needs to be a electrolyte such as water to start galvanic corrosion. Even under high humidity the aluminum oxide layer formed on the aluminum surface is sufficient to protect the pure aluminum below.
Looks like graphite thermal pads are fine for use on Cobs.
I would avoid sanding before installing cob. Sanding the heatsink would remove the aluminum oxide layer and may cause an issue.
Airwalker16
Well-Known Member
So how did the 100hr test go @robincnn ?