DIY LED lighting

[Splumph]

Might actually have him make it the whole length of the tank, figure it can't cost too much more, and the extra surface will only help dissapate the heat. Do you run any fans over yours or is all your cooling passive, also I remembered you talking about bolting the LEDs to the sink (for ease of removal/replacement), but do you think the arctic silver adhesive would do the job? I might actually start this tank this weekend, but I am planning to let it cycle for a while, I have an existing pc fixture to put over it in the meantime. Figure I can scrape funds to build this light over the next few weeks.

[Zombo]

You're going to want to attach the LEDs to the heatsink with screws and a thin layer of AC as a thermal conductive medium, as even if you visually see the HS and LED mount as shiny clean, on a very tiny scale, it's like a washboarded country road.

[evilc66]

The biggest reason to bolt them down is to increase the performance of the thermal transfer medium. Higher clamping pressures will ensure maximum surface contact for thermal transfer. The thermal epoxy works, but is a nightmare to remove if you need to change configurations or repair something.

 

That guy will cut for free, but you have to buy in 12" increments. If you want a 13" peice, you still have to buy 24".

[Splumph]

The biggest reason to bolt them down is to increase the performance of the thermal transfer medium. Higher clamping pressures will ensure maximum surface contact for thermal transfer. The thermal epoxy works, but is a nightmare to remove if you need to change configurations or repair something.

 

That guy will cut for free, but you have to buy in 12" increments. If you want a 13" peice, you still have to buy 24".

 

Good point, I cracked a chipset once trying to remove that stuff, figure i can drill the sink and maybe use some self tapping screws to hold everything down, I dont own a tap and die set that would make holes small enough to be practical. I was thinking about lapping the heatsink, but i figured that would be overkill, and alot of work. Besides, I figure if these LEDs fail due to overheating, waaay better ones will be out.

[coolwaters]

evilc66 wat do u use to drill screw slots? or are they just holes? and a nut at the other end?

 

btw sorry guys 2day and 2morrows event will set me back...

im planning to get my first ricordea this sunday. even if it kills me.

[Zombo]

evilc66 taps his holes

 

Wait, what?

[evilc66]

 

Splumph, go get yourself a cheap tap and die set. Harbor Freight has them for super cheap. They aren't designed for a production environment, but for the odd job they work fine. I have been using 3mm screws that are on 20mm spacing. Seems to fit all the different stars pretty well. I have noticed though that a lot of the cheaper stars have the solder pads really close to the mounting points, and the screw may come in contact with the pad. I suggest getting some nylon or phenolic washers to isolate them. Zombo, this is something you should look into also (sorry I didn't catch that before). These can be obtained at McMaster Carr.

[Splumph]

 

Splumph, go get yourself a cheap tap and die set. Harbor Freight has them for super cheap. They aren't designed for a production environment, but for the odd job they work fine. I have been using 3mm screws that are on 20mm spacing. Seems to fit all the different stars pretty well. I have noticed though that a lot of the cheaper stars have the solder pads really close to the mounting points, and the screw may come in contact with the pad. I suggest getting some nylon or phenolic washers to isolate them. Zombo, this is something you should look into also (sorry I didn't catch that before). These can be obtained at McMaster Carr.

 

Ok I think I have the design figured out in my head, so this will probably be my last question until I order the parts and start building it, do you use cooling fans on your light, or are they not needed?

 

Thanks for all your help

[evilc66]

Fans help. With the right sixe and type of heatsink you can run passively. The heatsink you are looking at will benefit from a fan. Don't need anything crazy. I have a low flow 80mm Panaflow fan blowing across the heatsink. Something like that will be more than adequate.

[coolwaters]

well in my experience a heatsink without a fan will burn u. i had about 6w of LEDs on a old chipset Heatsink and in about half an hour i got hot enough to hurt.

 

also saw a chart that said LEDs that are run at about 80F will last around 46k hours and around 120F it drops to 12k hours...

 

my cousin's internet router got a little hot so i installed some small heatsinks and that didnt help at all until i added a low flow PC fan. it made all the difference.

 

another good example is the HR-03

this guy is said to be the best graphics card heatsink EVER.

but its useless without a fan.

 

(evilc66 would probably say thats a bad example since its trying to cool down over 200w power lol)

 

we need to add HeatPipes to reefing =p

[evilc66]

I wouldn't say it's a bad example. It is a good heatsink. The great thing about heatpipes is it moves the thermal mass away from the source. It makes it harder for the area around the source to become saturated to the point of overheating. The big issue I have with any PC based heatsink is that they rely on the fan for 80% of it's cooling capacity. They are very high surface area, but low mass. When the fan is running they work perfectly. If the fan dies, you are in BIG trouble.

 

A heatsink with a higher mass will save you from trouble to a degree if the fan fails. As it sits right now, there is no perfect off the shelf heatsink for our DIY applications.

[Splumph]

I wouldn't say it's a bad example. It is a good heatsink. The great thing about heatpipes is it moves the thermal mass away from the source. It makes it harder for the area around the source to become saturated to the point of overheating. The big issue I have with any PC based heatsink is that they rely on the fan for 80% of it's cooling capacity. They are very high surface area, but low mass. When the fan is running they work perfectly. If the fan dies, you are in BIG trouble.

 

A heatsink with a higher mass will save you from trouble to a degree if the fan fails. As it sits right now, there is no perfect off the shelf heatsink for our DIY applications.

 

Look at some of the Zalman sinks, they are known for their passive cooling systems. That actually looks like a passive sink with, but I don't know. The drawback for PC sinks is they have a small usable area, since they are designed to go on IC's.

 

Would you guys mind posting a shot of the business end of your LED arrays, Im trying to get some ideas of how to wire it all together, what gauge wire did you use?

[evilc66]

Notice that all the Zalman heatsinks also have fans. The only passive products that they sell are for RAM and northbridge chipsets.

 

If you want to see pictures of my setup, go take a look in my thread. I have plenty of pictures in there.

[Zombo]

If you want to see pictures of my setup, go take a look in my thread. I have plenty of pictures in there.

 

Ditto.

[Splumph]

Foot firmly inserted into mouth...They were about 4 years ago, even had a completely fanless case, probably wont cut it with modern CPUs etc.

 

Ill have a look at your threads, thanks.

[evilc66]

I know the case you are talking about (cost about $1500 if I remember). Strangely enough, it would probably work better now with the Core2's than it did when when the P4's were around.

 

I've been heavy into computers for the last 15 years, and as anyone who is an enthusiast know, keeping up with heatsinks is almost a full time job. Needless to say I've learned a lot about heatsink design over the years. Even still now it can get confusing. General principals are all the same though; mass, surface area and thermal resistance.

[coolwaters]

alrite my light is finally done. for now. its basically the bare minimum to start...so it all looks half assed sorry about that.

 

just have to let the glue dry and mod my tank. this sunday im getting my test Ric. excited...

 

 

it looks great. i just cleaned out the tank. there nothing but saltwater pumps and a heater atm.

 

the light looks great never the less. i dont have a digi camera atm so sorry =p

trying to find where my dad is hiding it.

[coolwaters]

since im having a lot more trouble on the tank that i thought (along with long hours of work and School) i'v been forced to buy my ric next week...sorry guys.

 

btw im leaving my LED light on for about 8 hours a day to see how reliable it is. its been 3 days and still going strong. it isnt as blue as i imagined but its only 4 blue LEDs and 5 White LEDs.

[coolwaters]

yeah its down to $20 now

 

my friend gave me his old CPU heatsink (forgot the tank it home but i'll get it later) trying to limit it to 40watts. probably install 2 P7 and Some new UV and royal Blue LEDs.

 

wow my sister just stepped on my new light hood...snapped it but it looks repairable. and i spent all that time aligning it.....

 

i personally nice my simple light hood and it fits almost all CPU heatsinks.

[coolwaters]

heres the pics that i promised...last week.....

im going to say this now im a major procrastinator.

 

 

doesnt look that blue since SW is a different story...

 

if u get your hands on the lumens output info for your LEDs make sure its at least 1:4 (Blue to White) for a 10k look.

 

this was without the tank. very blue/violet.

that those pics were the same LED system nothing changed.

[coolwaters]

yes the exposed hood looks getto but it works...

 

going to need to cover the wires and stuff to prevent rusting.

 

if my water tests ok i'l get a ricordea ASAP.

[evilc66]

Actually, looks pretty cool! How many blues and whites are you running?

[coolwaters]

4 blues and 5 whites. i should have done the other way around but its pretty nice. im planning to add my UV LED later and will post the difference with the same settings as the one above.

 

if the UV does nothing (probably will) i'll be adding a few more blues.

[coolwaters]

nvm mind it seems that someone stepped on my array before and one of the blue LED isnt lighting up...

 

im going to need to resolder it. im beginning to hate the aluminum ring that cree has....

 

so this recap...if u want a 10k look get 100lumen blue to 500lumen cool white.

12k look is 130blue and 500white (ballpark numbers)

 

1 : 1 blue to white ratio will be crazy.

[Splumph]

Looks good, I missed how many LEDs you had on that unit, and what size tank is that?