@tony
Are you using your table saw for a bench?
I am. It's a 1959 Craftsman belt driven that I restored from my mom. Bought a piece of countertop to put on top. I also attached my router and table to it. That's crazy you noticed that.
Tony
Minimalistic multichip DIY LED build
- Thread starter maglofster
- Start date
I am. It's a 1959 Craftsman belt driven that I restored from my mom. Bought a piece of countertop to put on top. I also attached my router and table to it. That's crazy you noticed that.
Tony
mr.wilson
.Registered Member
No heatsink & no fan ?
Landsailor
New member
My Dad has his original 1955 Craftsman table saw and built cabinets rivaling that of any cabinet shop with it for years (until prefab cabinets hit the marketplace). I wish I had 10% of his woodworking knowledge!
Tony, are those 20W chips? Forced air cooling? (sorry if you've already stated this, but the thread is getting unwieldy.) I may be going that route if my heatsink source doesn't pan out.
Yes they are 20W chips. The heatsinks are 2 1" x 4" x 60" aluminum rectangle tubes. I have 6 50mm fans that blow into the tubes through holes that I cut out for them. FYI, 50mm fans are loud and I will be building an adapter to run larger fans that are quiet. If you have any other questions about my build please dont hesitate to ask.
Tony
The heatsinks are the rectangle aluminum tubes that the chips are mounted to. I cut holes for the 50mm fans so that they blow into the tubes. 6 fans total but but I hate how loud the 50mm's are. I'll be fabricating an adapter so that I can use larger quieter fans instead.
Tony
mr.wilson
.Registered Member
That seems light considering many 2-3w fixtures have overheating issues with a finned aluminum heatsink and fans mounted directly over the fins blowing down.
I've noticed throughout the thread that many of the projects have passive heatsinks that are undersized. I'm not talking about the fan cooled heat pipe CPU coolers, but the simple aluminum fin heatsinks like you see on 3w builds.
Maybe I'm overkill, but I thought I would mention it.
All info is good info. If my fans crapped it would overheat. With the fans running, max temp anywhere on the heatsink is 96 deg.
Tony
hillscp
Soylent Green is People!!
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My shop
I frickin love it!
TropTrea
New member
Keep in mind that different chips generat different amounts of heat at the same power levels. You can even take it further and even the same chip will generate considerably less heat at just a slightly lower power level. Most chips have there most effecient when running between 75C and 85C. If your running that hot most individuals will be afraid of overheating.
Lassef
Member
36 C is now problem if you have attached the chips properly. Try to measure at the chip´s backplate or very close to it. I have run (and several with me) this type of construction for a long time and in my case at higher temperatures (inclosed in a RSM 130 hood) Try to run the fans at 8-9 V and see how much the temperature will rise. You canv also use a temp controller for computers to tune efficacy against noises. The fans are much more silent if you underdrive them. According to the vendor it works up to 60 degree C (140 F) at the chip´s backplates but you may not exceed 50 C (122 F) in my opion. And of course the lower - the better with respect to efficiency and lifespan. In my constructions - the aim is a maximum around 35 - 38 C (95-102 F)
And according to lifespan - about three to four years from now, development has gone so far that you no longer want these Stone Age stuff at your aquarium
There has been many dreamchip´s in that time I have replace my lighting in my apartment with LED bulbs. Some of them have such a long lifetime so my grandchildren will inherit them
I have run the chip´s at my main aquarium at 35 - 39 C (95-102 F) for one and a half year now - nema problema. Normally I only run the fixtures at maximum capacity 3 - 4 hours a day and even a slight decrease in the intensity (read - little dimming) affect the temperature downwards.
I have to stress that the things I write in this post is true and after my experiences for the chip´s from my normal vendor - how it is with other chip´s with another orgin (or brand´s) - I do not know. However - in one of my constructions - running at 40 - 50 C (104-122 F) at maximum (4 - 5 hours a day) - there is 5 Cree XM-L included. Have run for 5 months now - without any proplems.
Sincerely Lasse
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Lassef
Member
I could not edit - of course I meant: 36 C is no problem if you have attached the chip´s properly.
Sincerely Lasse
BeanAnimal
Premium Member
Lasse,
Not to change the subject... but the LED lamps for replacement of incandescents have a LONG way to go. While the emitter may last 20 years with only 30% or so degradation in output, most of the drivers will die long before that. My brother purchased 4 Sylvania PAR30 lamps for his kitchen ($60 USD each) and 3 of them died within 4 months. They were replaced with Utilitech (Lowes brand here in the US) medium base led lamps ($37 each) and 2 of them have died. I have purchased 4-5 of different styles for trial here at my home and already (2) of of the 6 lamps have died (3 months). At $30-70 each, it is a joke and sad, because the light is SO MUCH better than the compact fluourescents and so much more efficient.
We have installed (12) 4" LED "trims" ($45 each) in his kitchen recessed lights to replace the halogens. They have been there a month and all are still working. Time will tell. Honestly, the cans only accepted 30W lamps and were not bright enough. The LED trims are 14W each and brigher than the 30W halogens or he would have never switched.
Not to change the subject... but the LED lamps for replacement of incandescents have a LONG way to go. While the emitter may last 20 years with only 30% or so degradation in output, most of the drivers will die long before that. My brother purchased 4 Sylvania PAR30 lamps for his kitchen ($60 USD each) and 3 of them died within 4 months. They were replaced with Utilitech (Lowes brand here in the US) medium base led lamps ($37 each) and 2 of them have died. I have purchased 4-5 of different styles for trial here at my home and already (2) of of the 6 lamps have died (3 months). At $30-70 each, it is a joke and sad, because the light is SO MUCH better than the compact fluourescents and so much more efficient.
We have installed (12) 4" LED "trims" ($45 each) in his kitchen recessed lights to replace the halogens. They have been there a month and all are still working. Time will tell. Honestly, the cans only accepted 30W lamps and were not bright enough. The LED trims are 14W each and brigher than the 30W halogens or he would have never switched.
BeanAnimal
Premium Member
No, not really to any extent. Sure there is a difference in a cutting edge emitter and an older lower efficiency, but they are all in the same ballpark. Lets say 2/3 of the power fed to the "chip" ends up as heat. In reality it may be 63% or 75% but it is the better part of the power consumed (converted) by the chip.
Again, we are fiddling with a few percentage points when the big picture is roughly 2/3 to 3/4 of the energy put in is directly converted to heat.
So, without doing a lot of thermal gymnastics, the heatsink needs to be designed to handle roughly 100% of the expected full rating of the "chip". That is a 200W "chip" needs a heatsink capable of dissipating 200W.
NewBostonConst
Premium Member
Can you list what LEDS you are using. You said they are on the blue side.
I looked back alot of pages and couldn't find where you listed it.
Thanks in advance.
I have 6 x 455's, 4 x 445's, 2 x 420's, 2 x 10000k's, 2 x 14000k's and soon to be 2 x Cree XM-L cool whites
Tony
TropTrea
New member
Actualy it is a blancing act. To much heat will burn the chip out I agree but if your looking at effeciency it is almost the other way around.
So lets look at the difference between two chips that have 2/3 and 3/4 of there energy going too heat. If we put 1,000 units of energy in one chip running at 3/4 going to heat we end up with 1/4 going to light or 250 units of light. Now look at the other chip with only 2/3 going to heat that chip then has 1/3 going to light or 333 units of light.
Now when your constructing a lighting fixture that needs to put out 100,000 of these units of light your looking at a system that runs on 400 chips or one that runs on 300 chips. With each chip consuming the same amount of total power.
Another thing to keep in mind is where we are measuring heat on these chips. Ratings are actualy taken at the emitter rather than the back of the heat sink. There can be a considerable difference between these two points since heat distributes itself in the same manner as light does linearly. On an XT-E LED at 85 C it is rated at 100 percent effecient, but at 25C it is rated at 116% effecieny and at 150 C it is 82% effecient. However these effeciency ratings are comparing ma to a constant current. In reality as the temperature increases the thermal resistance decreases which will result in a lower voltage to required to maintain that current. the change in resistance is great enough to basicly flip this effeciency chart if your comparing it to wattage rather than just current.
Now you might think this is irrelevent considering we are using multi high wattage LED's but in reality those multi chip 20 Watt to 200 Watt LED's are just a combination of these smaller LED's mounted together. Since you might have 9 to 40 LED's mounted so close together they do generate more heat collectivly for the heat sink to remove.
Yes cooling is important for the llongidity of the LED. A LEAD running at 25C or 85C will probably last longer than what we will be using it. However when your talking 100C or higher its life span starts reducing drasticly. Besides this do we want want a 150 C heat source located inches away from our tank.
Lassef
Member
No problems with changing the subject - and two reasons for that.
1) It seems that we agree
2) It is my favorite subject
I do not know the situation in USA but here i Sweden - the most popular "spot" lighting is done with 12 V of this type
People that sell replacment LED lamp for this is more or less criminal IMO. This because the same thing that we have discussed here earlier. This bulb is driven by a constant voltage source and if you put that type of drivers (with some exeptions) to a Power LED bulb - it will soner or later burn up. Belive me I did that with rather many 5 years ago
But during the last years there has been a change and replacment bulbs for the normal grid (in Sweden 230 V AC) has been more common. EU has banned the old Edison bulb in higher wattage so both Philips and Osram has wake up. Philips has a serie of spots and "Edison" bulbs that is very good and I realy think that the one that I have in my livingrom will be there for my grandchildren. But it cost about 80 $
Here in Sweden - we have a huge player according to furnishing and lifestyle - IKEA.
They have had a low profile in terms of LED general lighting but the last six months has introduced a product line in this area. A 5-watt spot for the normal grid cost around $10 and it give a better light than both halogen and compact fluourescents IMO. I have had some for 5 months now - we will see if the quality is good. But normaly - when IKEA introduce something new of this type - it change the market here in Sweden
In my job I start the replacement five years ago than now we nearly not install anything else than LED for general lighting and spot lighting. But we are very carefully with the quality (we do not use IKEA stuff
) we can take that investment because most cost we have with the general lighting is replacment with new bulbs or fluorescent. If we can rise the life span with a coupple of years we save money and that we can do today with LED of the right quality.Around 80 - 90 % of the LED Bulbs I installed 4 - 5 years ago i still working. I have change a lot of drivers in one type but on other hand I have changed 60 % of the electronic drivers for our fluorescent during the same time
Sincerely Lasse
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