Step into my grow room

malachii said:
I want to implement something to this lighting configuration - using 18 Vero 10's arranged 3*6 or 6*3. I could power this all with one driver similar to this, but I'm nervous about thermal runaway. To avoid this I may prefer to use 3 drivers instead. This implies I can have either 3 or 6 on a string. If I go this route, how should I select my drivers? I intend individual COBs to run at 350 mA. These Vero's are the ones I'm looking at: http://www.digikey.ca/product-search/en?v=976&mpart=BXRC-40E1000-B-03

My understanding of COBs is fairly limited, but if I was working with regular power supplies (e.g. a battery), and regular LEDs, I would add up the voltage requirements when in series. This would put us at 81v if I put 3 in a single series. Using "constant current" power, does this mean that the driver will target 350 mA, and increase voltage across all 3 in series until it's satisfied? What 'spec' to I look for? It seems to be hard to fine. For example, the following is reasonably priced and seems to support the appropriate voltages at the desired draw: http://ca.mouser.com/ProductDetail/Mean-Well/APC-35-350/?qs=sGAEpiMZZMt5PRBMPTWcafwf9UxD7OdlOvQxcoYbEiA=

Am I way off base?

Thanks for the help!
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Interesting thread to choose for your question(s).
 
malachii said:
Hmm, maybe I chose the wrong place to post this. Is there a more appropriate thread or forum? If so, I'll take this down.
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I advise organizing your question(s) so that viewers/readers can easily approach solving your problems. Sometimes numbering them helps others address issues quicker.

Yeah, I'd either post a cleaner version of the original on either/both How to Power LEDs and/or All Things Vero.
 
AquariusPanta said:
I advise organizing your question(s) so that viewers/readers can easily approach solving your problems. Sometimes numbering them helps others address issues quicker.

Yeah, I'd either post a cleaner version of the original on either/both How to Power LEDs and/or All Things Vero.
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Thanks guys. I've removed my post - I will post it in the appropriate forum. I wasn't even aware of that thread. I'm back on these forums after a few years, and well, things have changed ;) Apologies.
 
I always use Google and search for my question plus RIU. Usually sends me right to the thread I want :)

You can also just browse the Forums.
 
Mohican said:
I always use Google and search for my question plus RIU. Usually sends me right to the thread I want :)

You can also just browse the Forums.
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Mohi, every time that I see your avatar, I wonder what I'm looking at. Is it a seed of some sort? A dragon's eyeball? A planet on a plate? I give up :wall:.
 
MrFlux said:
C-channel (U profile) would work great.


I don't see the attraction here. The COBs can't be put in the center because of the airgap from the spacers. If they are staggered then you might as well use two loose profiles.

Btw you can use JB weld to glue profiles together to create larger heat sinks.
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MrFlux thank you very much for your patient assistance here. You're awesomeness is self-evident! I have some heat sink questions to discuss.

I had no idea that standard aluminum stock from the hardware store would suffice as heat sink. I thought heat sink material was a "special" type of aluminum.

Does JB Weld transfer heat? I thought it was simply a plastic resin epoxy that worked on metal.

If more surface area exposed to moving air makes a more efficient heat sink, wouldn't gluing two sides of C channel or Angle aluminum together only eliminate two sides from airflow making it less efficient? I just ask because I have no experience with heat sink and this theory makes sense to me.

Do you think that aluminum square tube 1" x 1/20" thick would make a good heat sink for Vero 10s? I would think that square tube aluminum, since it offers four sides, would be more efficient than C channel because there is more surface area for air to flow over and dissipate better especially if there where fans at one end blowing in and over the tubes.

Also, for 5 Vero 10s, what about stock aluminum angle 3/4" wide x 1/16" thick? It's what we have here at Home Depot.

I was also thinking that thinner aluminum stock may work better than heavy thick stock or plates I have seen because thick stock would retain heat longer than thin stock and therefore be less efficient for dissipation with active cooling. Are the stock aluminum thicknesses, 1/16" and 1/20" I have mentioned here too thin?

Any feedback greatly appreciated!
 
The thicker stock would spread the heat faster, reducing the gradient from the hot spots to the cool spots. This lowers the junction temp and increases the heatsinks ability to exchange with the air at the same time. If you run your Veros very soft and spread far apart, you might be able to get away with C channel. The cheapest heatsink profile at heatsinkusa is the 2.08", great for Vero 10s and passive cooling.
 
SupraSPL said:
The thicker stock would spread the heat faster, reducing the gradient from the hot spots to the cool spots. This lowers the junction temp and increases the heatsinks ability to exchange with the air at the same time. If you run your Veros very soft and spread far apart, you might be able to get away with C channel. The cheapest heatsink profile at heatsinkusa is the 2.08", great for Vero 10s and passive cooling.
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Ahhh, that makes sense. I suppose mass has a lot to do with it. I was using the analogy of a car radiator and how thin and numerous the cooling fins are, but there is still a lot of metal there too.

I assume there is a formula to determine heat sink efficiency, but my background is not in engineering and I didn't take calculus or physics in college...sigh...

BUT...I know basic electronics and can splice, test and solder as good as anyone. I really do appreciate the reference to the heat sink Supra, I am all about spending money for quality as long as I know I have the correct parts that are matched properly for the best efficiency. Thanks again man.
 
wirat said:
Ahhh, that makes sense. I suppose mass has a lot to do with it. I was using the analogy of a car radiator and how thin and numerous the cooling fins are, but there is still a lot of metal there too.

I assume there is a formula to determine heat sink efficiency, but my background is not in engineering and I didn't take calculus or physics in college...sigh...

BUT...I know basic electronics and can splice, test and solder as good as anyone. I really do appreciate the reference to the heat sink Supra, I am all about spending money for quality as long as I know I have the correct parts that are matched properly for the best efficiency. Thanks again man.
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Here is the cost for 5 ea. approx 1M (39") long. A $5 cut fee is not listed. Not bad at all!
HeatShrink.jpg
 
Hello, this is my first post here on RIU and I must say this cab is amazing! Everything is so clean and the girls love the lights.
I was going to buy a couple of hans panels but I like these bars a lot, will study more and maybe I'll try making my own.
Do you have building plans for this "Ikea Kanna" closet? I want to build something very similar and it would be a great starting point.

Thanks!
 
Hi guod,

The current test for Vero 13 is at 500mA, and this driver is only supplies 350mA. That's why I was looking at the 10's. Won't that underpower the cob? I'm currently trying to figure out the spec sheets and how everything works.
 
You are just making a lot more wiring for yourself. No other disadvantages that I can think of. Under powering = higher efficiency.
 
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