Custom Heatsinks
- Thread starter vshortt
- Start date
Have you Googled?
http://www.birminghamaluminium.com/heatsinks_home.php
http://www.birminghamaluminium.com/custom_profiles.php
Sounds v.expensive for 16 feet of heatsinks - you sure you can't find a close enough profile? And 4 feet long in one piece or a more realistic 8 x 6" sections?
http://www.birminghamaluminium.com/heatsinks_home.php
http://www.birminghamaluminium.com/custom_profiles.php
Sounds v.expensive for 16 feet of heatsinks - you sure you can't find a close enough profile? And 4 feet long in one piece or a more realistic 8 x 6" sections?
yes, I have googled and didn't really find anything that would suit my needs.
What I'm working on is an LED light, something that would replace a flourescent fixture.
My thought was to have a profile that was finned on top, flat on bottom, but the fins would collectivley make a "round" profile. It would essentially look like this:
The 3W LED's would sit in the small recess on the bottom of the heatsink in a row.
What I'm working on is an LED light, something that would replace a flourescent fixture.
My thought was to have a profile that was finned on top, flat on bottom, but the fins would collectivley make a "round" profile. It would essentially look like this:
The 3W LED's would sit in the small recess on the bottom of the heatsink in a row.
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Andrew Cowan
Senior Member
Good point. Hot air rises, so it would get trapped between the fins. Is the light fitting itself going to be made of metal?
A
A
lanternfish
Senior Member
A couple of small fans should provide adequate airflow.
If you are going to use fans do you need such an expensive extrusion.
If just a few off 'prototype' design why not fabricate and save money (and weight).
Have you done any calcs to work out the heat dissipation you need?
Will you be using nice quiet Papst (or other branded) fan or noisy cheapy jobbies from the Beijing fan company?
I would have thought that if you scaled up a small heatsink you could avoid a fan. If you designed your fins you could optimise convection in the intended orientation too. Hot air (!) isn't going to get "trapped" in an open design but the fin geometry will affect convection/conduction.
How will your LEDs be 'connected' to heatsink?
If just a few off 'prototype' design why not fabricate and save money (and weight).
Have you done any calcs to work out the heat dissipation you need?
Will you be using nice quiet Papst (or other branded) fan or noisy cheapy jobbies from the Beijing fan company?
I would have thought that if you scaled up a small heatsink you could avoid a fan. If you designed your fins you could optimise convection in the intended orientation too. Hot air (!) isn't going to get "trapped" in an open design but the fin geometry will affect convection/conduction.
How will your LEDs be 'connected' to heatsink?
lanternfish
Senior Member
Having re-read the posts I cannot help but wonder if the heatsink design is a bit of an 'overkill' in terms of the heat it will be required to dissipate.
If it is more of a design feature, there are quite a number of aluminium 'designer' fittings that could be modified to suit.
As for the fans, you probably only need one at each end to get air flow moving through the fins. Fans mounted horizontally on the top could be less efficient.
If it is more of a design feature, there are quite a number of aluminium 'designer' fittings that could be modified to suit.
As for the fans, you probably only need one at each end to get air flow moving through the fins. Fans mounted horizontally on the top could be less efficient.
So I ditch my 4ft fluoro lights on the kitchen ceiling and replace them with 4ft heatsinks with fans on them (in some orientation I can't quite understand) and a few high power LEDs spaced out along the length - is that the idea? Just trying to understand - and sell the idea of the wife having to get the feather duster out to remove all the small animals that will love their nice warm and dark homes betwen the fins 
Oh Martin, you are cynical!
A lot of the design will, of course, depend on how many LEDs to be used.
I would be tempted to look at designs already out there, then do some power calcs, look at currently available heatsink designs and extrapolate.
4ft of that extrusion would probably weigh half a ton.
And if in the house then consider how painful fans would be.
A lot of the design will, of course, depend on how many LEDs to be used.
I would be tempted to look at designs already out there, then do some power calcs, look at currently available heatsink designs and extrapolate.
4ft of that extrusion would probably weigh half a ton.
And if in the house then consider how painful fans would be.
Andrew Cowan
Senior Member
...especially for the poor insects who decide to make a home in the heatsink.
BeanieBots
Moderator
Or just buy an LED replacement tube that fits into the existing flouro fitting.
They do exist and look/feel just like a flouro tube.
Can't recall the last site I looked at but Google should find the devices.
As for heatsink requirements, the major problem is thermal resistance between LED and heatsink. After that, not many W/degC are required.
For a "feel" I have a 10W LED fitted to a heatsink approx the size of a MR16 halogen lamp which only gets about 10 degC above ambient with no forced air cooling.
They do exist and look/feel just like a flouro tube.
Can't recall the last site I looked at but Google should find the devices.
As for heatsink requirements, the major problem is thermal resistance between LED and heatsink. After that, not many W/degC are required.
For a "feel" I have a 10W LED fitted to a heatsink approx the size of a MR16 halogen lamp which only gets about 10 degC above ambient with no forced air cooling.
Seems to me I've already seen a TO-3 heatsink with that profile, so there is someone set up to extrude them. Just remembered where I saw it - on my water heater. The slot in the center is 1-1/4" wide, the fins are 1" tall, and the width is 3-3/4". Shaped like the drawing - only 8 fins total.
I think they were in the "Wakefield" catalog. Machined and anodized and drilled for 2 TO-3 parts. The stock extrusion is probably cut to truck lengths. Mine is 4" long.
Some new heatsinks aren't extruded at all, the (very many/very thin) fins are anchored in a piece of bar stock with epoxy or a metal to metal interference fit. "Electronic Design" did a article on them recently.
I think they were in the "Wakefield" catalog. Machined and anodized and drilled for 2 TO-3 parts. The stock extrusion is probably cut to truck lengths. Mine is 4" long.
Some new heatsinks aren't extruded at all, the (very many/very thin) fins are anchored in a piece of bar stock with epoxy or a metal to metal interference fit. "Electronic Design" did a article on them recently.
LOL, I love the debate!
Actually, these are going to be aquarium lights. I agree that they will be heavy but the heatsink part itself will actually be part of the asthetic design.
Right now I"m just kicking the idea around - it's more of a feasability study than anything else. My thought would be to have the entire "housing" for the LED's be the heatsink, which is why I came up with this design. I Don't expect the extrusion to be any larger in radius than a flourescent bulb, so that might bring the weight down.
I have done the calcs and yes the heatsink wouldn't be overkill, but it's also a design factor, they would "look" finished and be easy to install. I'm not sure about the "wheres" and "hows" to mount the fans yet either.
There are going to be, at a minimum 20 1W or 10 3W LED's depending on the light configuration. There are a number of things to take into consideration when creating an aquarium light for a saltwater aquarium.
Many of the living creatures in a saltwater aquarium use light to actualy synthesize food (like anemones and corals) so this light will be MUCH brighter than a standard CCF light.
There are a number of straight flourescent light replacements on the market right now, most of them use small SMD mounted 30ma LED's to create a similar light pattern. These lights are almost 10 times the brightness.
Par values are also critical, so there is a mixture of White LED's, Blue LED's and Magenta and Red LED's.
Actually, these are going to be aquarium lights. I agree that they will be heavy but the heatsink part itself will actually be part of the asthetic design.
Right now I"m just kicking the idea around - it's more of a feasability study than anything else. My thought would be to have the entire "housing" for the LED's be the heatsink, which is why I came up with this design. I Don't expect the extrusion to be any larger in radius than a flourescent bulb, so that might bring the weight down.
I have done the calcs and yes the heatsink wouldn't be overkill, but it's also a design factor, they would "look" finished and be easy to install. I'm not sure about the "wheres" and "hows" to mount the fans yet either.
There are going to be, at a minimum 20 1W or 10 3W LED's depending on the light configuration. There are a number of things to take into consideration when creating an aquarium light for a saltwater aquarium.
Many of the living creatures in a saltwater aquarium use light to actualy synthesize food (like anemones and corals) so this light will be MUCH brighter than a standard CCF light.
There are a number of straight flourescent light replacements on the market right now, most of them use small SMD mounted 30ma LED's to create a similar light pattern. These lights are almost 10 times the brightness.
Par values are also critical, so there is a mixture of White LED's, Blue LED's and Magenta and Red LED's.
JoeFromOzarks
Senior Member
This may sound silly, but my favorite "custom" heatsink material is Aluminum Flashing - it's inexpensive, available about everywhere, and it cuts, rolls, bends, drills and shapes easily!
BeanieBots
Moderator
As soon as I read that I thought 'I hope this isn't a salt water aqaurium'.
Then I read.
Aluminium and salt water don't last very long together.
Be VERY careful. The aluminium will corrode very quickly at the first sniff of salt, then it will dissolve and the extremely toxic product will kill all your fish and invertibrates.
Dip your heatsinks in varnish (non marine because that too is a fish killer by design) and then leave to dry for two weeks followed by two weeks in a bucket of tap water to leach out the solubles. Change the water every day during the soak period.
Good luck!
BeanieBots
Moderator
Now that LEDs are bigger, brighter and cheaper I may well have a go at LED aquarium lighting myself. Spent many months getting the flouros to dim, dimming LEDs will be a doddle in comparison
I was thinking of taking an easier route with a bank of these:
http://www.ultraleds.co.uk/60cm-cool-white-tube-extra-unit-p-2105.html?osCsid=e82ef754b13d3716706d5a4489702a43
a few of these
http://www.ultraleds.co.uk/water-proof-unit-p-2156.html?osCsid=e82ef754b13d3716706d5a4489702a43
and/or maybe some of these
http://www.ultraleds.co.uk/g24d-65w50w-light-output-cool-white-p-2233.html?osCsid=e82ef754b13d3716706d5a4489702a43
I was thinking of taking an easier route with a bank of these:
http://www.ultraleds.co.uk/60cm-cool-white-tube-extra-unit-p-2105.html?osCsid=e82ef754b13d3716706d5a4489702a43
a few of these
http://www.ultraleds.co.uk/water-proof-unit-p-2156.html?osCsid=e82ef754b13d3716706d5a4489702a43
and/or maybe some of these
http://www.ultraleds.co.uk/g24d-65w50w-light-output-cool-white-p-2233.html?osCsid=e82ef754b13d3716706d5a4489702a43
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JoeFromOzarks
Senior Member
The aluminum flashing or me, after I've been discovered stripping my home of the flashing?
westaust55
Moderator
@Vshortt,
Believe what you are looking to create is already on the market.
You just have to track down who is making them for the existing fluro tube replacement manufacturers.
Only a week ago, I saw some LED replacement tubes for the conventional Fluorescent tubes.
Have a look at SH Lighting in the UK at: http://www.shlighting.co.uk/shlighting_led_products_home.asp?newsID=49
Believe what you are looking to create is already on the market.
You just have to track down who is making them for the existing fluro tube replacement manufacturers.
Only a week ago, I saw some LED replacement tubes for the conventional Fluorescent tubes.
Have a look at SH Lighting in the UK at: http://www.shlighting.co.uk/shlighting_led_products_home.asp?newsID=49
I am sure there is something similar on the market, it's just not targeted at the aquarium market. Standard CFL's don't work with a saltwater aquarium.
For example, I'm currently running a 400Watt Metal Halide on my aquarium. Soft and hard corals as well as many anemones just require so much light at a specific wavelenght.
the other part is that I am programming a pretty sophisticated light controller. it will have a number of different settings and the brain not only will control the lights, it will also control pumps, filters, etc.. it's going to be a complete unit that handles all the electronics for the aquarium, monitor water quality, etc...
The LED's will be highly configurable and even have the option to mimick a "lightning storm" as well as several other weather types. This means I need to be able to manage each led individually... hence the need to create my own lights.
I appreciate all the hints about "premade" lights, but they just don't fit the bill for my project.
I think I have come up with a great solution for the heatsink, and it's cheap and lightweight. You can get a number of different aluminum extrusion patterns on that great big auction site. I am going to pick up a few pieces for about $30 and see how well they will work as the heatsink. If they work well, they will definatley be stout enought to act as the support as well... I'll let everyone know what kinds of temps I get with this setup and try and post some photos.
If it works, this would be a great solution for some seriously CHEAP heatsinks for high power LED's. to the tune of pennies for each LED if you chose to cut up the extrusion and make individuals.
We'll see what happens. Ingenuity is the name of the game, right?! At only a few bucks per LED, I can afford to destroy one or two trying this out!
For example, I'm currently running a 400Watt Metal Halide on my aquarium. Soft and hard corals as well as many anemones just require so much light at a specific wavelenght.
the other part is that I am programming a pretty sophisticated light controller. it will have a number of different settings and the brain not only will control the lights, it will also control pumps, filters, etc.. it's going to be a complete unit that handles all the electronics for the aquarium, monitor water quality, etc...
The LED's will be highly configurable and even have the option to mimick a "lightning storm" as well as several other weather types. This means I need to be able to manage each led individually... hence the need to create my own lights.
I appreciate all the hints about "premade" lights, but they just don't fit the bill for my project.
I think I have come up with a great solution for the heatsink, and it's cheap and lightweight. You can get a number of different aluminum extrusion patterns on that great big auction site. I am going to pick up a few pieces for about $30 and see how well they will work as the heatsink. If they work well, they will definatley be stout enought to act as the support as well... I'll let everyone know what kinds of temps I get with this setup and try and post some photos.
If it works, this would be a great solution for some seriously CHEAP heatsinks for high power LED's. to the tune of pennies for each LED if you chose to cut up the extrusion and make individuals.
We'll see what happens. Ingenuity is the name of the game, right?! At only a few bucks per LED, I can afford to destroy one or two trying this out!