No way to get proper heat sinks in Europe

[bvolt]

Hey guys - listen... many CPU coolers (with fans) will cool a Vero 29 or any other COB - even a CLU058-3618 @ an incredible 520w, actively.

This is not a "bad" option.

Personally, I believe the reason so many people are shipping insanely heavy chunks of metal thru the mail is the "efficiency-craze" started by growmau5 in his videos - and look, even ChilLED uses active cooling technology in its products (keeping LEDs properly cooled extends longevity).

Guys, it's only 12v. Embrace active cooling if you live Europe.

[Ted]

I know you all are looking for data regarding heatsinks, but its a rather complicated process to calculate that data if the heatsink manufacturer hasnt done testing on it.

Aavid, an COB heatsink producer has a tool to calculate heatsink needs here... http://aavidgenie.com/online-thermal-de ... 4QQAvD_BwE

You could also look at their datasheets as they show temperature increase over wattage for all of their heatsinks. Then you might be able to approximate your needs if you cant buy one of their heatsinks from the states.

I just told someone in the midpower section to just use wood for their strip build, as long as there is air moving against it. Strips are more efficient than cobs, and the heat is more difuse. For a cob, you’re absolutely going to need a heatsink, but a sheet of aluminum would suffice.
As I mentioned there in the states, the same place I would buy nuts and bolts also has all the aluminum I would ever need (I live about 200yds from a home depot, which I could build an entire house with whats in that store), so its different for me to hear that you all cant get your hands on aluminum.

Hope that helps!

[majorana]

A sheet of aluminum would be sufficient for most PCB uses, and definitely strips. Aluminum sheets and U-channels are readily available at at hardware store even in Europe. The tricky part is heat dissipation with COBs, which generate much more heat on a much smaller surface. Passive heatsinks for those are designed with pins/fins to maximize surface area. Yes, it's a piece of metal, but it's actually expensive to produce. And heavy to ship. It's just the way it is, not some secret untapped market.

In hindsight, I should have bought Alpine CPU heatsinks+fans for my Vero29's for a fraction of what the passive heatsinks cost, given that any fan would have handled the relatively short life of that fixture. (Which will move on to light up some orchids soon enough.) I understand where OP is coming from, even if the tone of voice rubs me the wrong way.

[bvolt]

What did you guys do, before those heat sinks were available?

Obviously, I can only speak for myself on this topic.

Before the dismantling of prohibition began and these heatsinks became ubiquitous in the US, one place indoor gardeners sourced supplies from was the corals and the reptiles-as-pets community - so, you may find LED supplies sold by such vendors (Reef Builders / Drs. Foster and Smith).

My first build, I used a simple piece of extruded, bar-type anodized aluminum ~ 6" wide, by 20" long with 1" fins every .5" (36" long may have been better) - with a simple 12v fan mounted so the fan blew air down onto/over the bar.

I mounted 3 - Vero 29 Ds (w/Angelina optics) with paste and screws to the bar for 250w at 2.1A... a longer bar may have eliminated the need for a fan.

Recently I've been looking at discarded PC cases...

1. invariably, one side of the PC case is going to be sheet-aluminum, perfect for attaching a mounting bracket and paste
2. Attach a modest heatsink to the inside of the case (opposite each COB mounting bracket)
3. Most often, there is already a fan mounted to a grill, use it
   • If it's not too heavy, I leave all the electronic components in place (more surface area to pass air over for cooling, as long as mounting is conductive)
4. Use a Meanwell B-type driver, throttled down to min

When I power it on for the first time I monitor temps and throttle power back to max, if possible.

Remember, it's the temps at the solder junctions that you are concerned about - not the fixture's overall temperature (how it feels when you touch the outside of it).

FYI - your crop is completely unaware of your thermal management choices, this should never be a consideration.

Also, is trade with Australia as restrictive as the US (for you guys in the EU)? Cutter is a great source for components...

[bvolt]

Strips are more efficient than cobs, and the heat is more difuse. For a cob, you’re absolutely going to need a heatsink, but a sheet of aluminum would suffice.

Definitely, right? Both heat and light are more diffuse with mid-power LEDs, when they're properly constructed in arrays...

[Ted]

Strips are more efficient than cobs, and the heat is more difuse. For a cob, you’re absolutely going to need a heatsink, but a sheet of aluminum would suffice.

Definitely, right? Both heat and light are more diffuse with mid-power LEDs, when they're properly constructed in arrays...

I think its they way to go, but COBs are certainly cheaper. Midpower diodes are like 0.2-0.3 watts each, so on a square inch you might have 1-2 watts, whereas you’re pushing 50+ watts in a square inch in a cob, and then you start running into thermal management issues.

I put my strips on heatsinks from heatsinkusa because I was worried about frying the LEDs, but it was definitely overkill in hindsight. The heatsinks barely get warm to the touch.

[bvolt]

In hindsight, I should have bought Alpine CPU heatsinks+fans for my Vero29's for a fraction of what the passive heatsinks cost, given that any fan would have handled the relatively short life of that fixture.

M - agree 100%.

I think beyond striving for efficiency, one of the reasons for the "passive cooling craze" is... early on, while trying to convince critics of LEDs-for-growing-cannabis that LEDs could compete with HPS - the idea that a fan might fail and burn up a COB was distressing (even if extremely rare) because of the COB's prohibitive cost.

So, for growers that don't visit their crop often (or the average internet-user finding fault with any idea not their own), a passive option was necessary.

But I'm in my garden multiple times daily - I'll live if I lose a fan (still waiting for this to happen to anyone, anywhere) and the COBs I'm using cost between $9-$22... I think I'll walk the wild side.

[almansor]

@ majorana: sorry if I offended you. It really wasnt my intention to offend you. By "back that up" I ment, back those facts up with data...just like...could you prove that those stripes are the real thing.
I fd it up. English is my second language. So youre right, it is a language thing.

Please forgive me.

[bvolt]

I'm sure no offense was meant... no one here is interested in that, and it's just not tolerated.

Also guys, I started thinking a bit more about thermal management using commonly available materials - not just hunks of metal, but strategically arranged, and most importantly, under extreme pressure:

Fins_N_Fans.png (1.31 MiB) Viewed 1329 times

Hopefully you can get the idea from these images.

The U-channel or L-bracket, or honeycombed aluminum sheets/strips will create heat sinking fins (in addition to those actual heatsinks w/thumbscrews) which will increase the effectiveness of the fans.

• If your enclosure had those heatsinks w/thumbscrews - they can be used to generate quite a bit of downward pressure to keep everything in place and provide proper thermal transfer

This is just the start of an idea, which I'm sure can be improved upon.

[oozing]

Ordering from the US is not an option due to custom taxes...they are astronomical. I have to say, this is my first build and I am a little bit on a budget here, so I dont wanna spend more than 20 bucks on a single heat sink, concidering I need 6 of them.

I was and still am in the same boat as you mate.
I have 2 builds behind me, COBs from Kingbrite and QBs from HLG.
I been down all the suggestions presented to your thus far.
Your best option is definitely Kingbrite. They are legitimate and sends you pre-drilled, pre-tapped sinks. They may very well be the cheapest price you can find and will save you a lot of time messing with heatsinks.
Ask them to write different a amount on the shipping papers. For me, they put down $150 on and order of $650. That alone mitigates most of your taxes issue.
Surprisingly, HLG do the same. They mark down the amounts drastically. I mean, way down I didn't pay import tax, customs, anything! on a ~$550 order. Their intl. shipping is insane. HLG cover free shipping within the US on the backs of intl. buyers. Still, I love their products and am waiting to get more.
Only one address for drivers and strips for me: Arrow. They offer free INTERNATIONAL shipping. If I need 2 drivers, I order them separately with 3 days between orders. No customs, no taxes. Split your orders there and try to keep them as low as possible but still get free shipping.
You can order drivers from Kingbrite too, they will be a bit cheaper but you will pay for shipping and maybe taxes (depending on the total amount).
To get to Kingbrite, find their store on Alibaba and contact them on the site. Say what you are interested in and they will move the correspondence to email and you're set from there.
Personal opinion on active cooling: go for passive. You pay just a little more for metal and shipping and get ease of mind. Active cooling is just adding failure points and complexity to your build in my opinion. For me I like being passive as part of the passive cooling thing
Hope that helps