Minimum Specs for CPU Heatsink/Fan on COB?

Trying to figure out the best combination of efficiency and price on a heatsink/fan for a 18 chip light. I suppose at that point, nothing is really economical. It may even be best to go passive with that many chips, but I'm concerned about the weight of 3 passive heat sinks in my PVC tent. Pretty sure I'm paying a pretty penny whichever route I go, so may as well save the stress on the tent. Is a 92mm fan the lowest I want to be using, or can I get away with an 80mm fan?

@HockeyBeard - Here is a page from CDIweb's LED site. https://led.cdiweb.com/FeaturedProducts.aspx?type=11144
There are a lot of options for under $15 each.

You can use small heatsinks on small cobs...

Yeah, I'm only going to drive these 2530s with a HLG-240C-700, so they won't be driven too hard.

@nevergoodenuf Those all look passive. So, at 700mA, I shouldn't have to dissipate more than 35W of heat? Could possibly get away with a pin-style passive?

Sorry, habit, I no longer want to play with fans. Here is what I meant-https://led.cdiweb.com/FeaturedProducts.aspx?type=11145
Are you sure you want to use that driver?? You are playing with some serious voltage there. Make curtain that all wires have the right ratings to handle it.

If you are using holders you can measure the hole distance and email [email protected] and she can probably find something to work for you. Im not currently in the market for heatsinks, but the
MODULED 9950-B @ about $7 each would work passively if the hole spacing is correct. She confirmed that there are holes built in that work for the ideal 3590's holders for me.....

nevergoodenuf said:

Sorry, habit, I no longer want to play with fans. Here is what I meant-https://led.cdiweb.com/FeaturedProducts.aspx?type=11145
Are you sure you want to use that driver?? You are playing with some serious voltage there. Make curtain that all wires have the right ratings to handle it.

Click to expand...

I'd have no problem using passive if I was sure they'd hold up. I just can't find a driver that suit my needs well without running up my budget terribly. That 240 is the only thing I can use 2 of to run the entire 18 chip array. It's not ideal, that's for sure. I'm open to a redesign, but I can't figure out an efficient way to cover most of my 8x4 tent (my plan was 3 6 chip bars) without running my costs through the roof.

Not trying to deter you, just want to make sure you know what you are working with. Why don't you just start with half, run shorter plants at a lower wattage per square foot, until you can afford to fill the tent? My lowest watt per square foot right now is 25w per square foot, only because I couldn't get the 3rd light built in time.

I need to be able to veg everything I move into my flower room, which is 8x10, evenly and effectively. The goal capacity is 8 plants in octopots. The footprint on that is comparable to a 10G pot. I was only able to fit 6 under the T5. Not only that, but one of my bulb sockets in the T5 went out. I know I'm working with a higher voltage driver, so I'll get thicker gauge wire. The input voltage is still going to be 110V.

How would you effectively cover that space?

The little wires going through your COBs will be over 300 volts, that's all I'm saying.
If you look at my set up, it will have you all screwed up.

Yeah, 9 @ ~35W, you're not kidding.... Makes it almost worth it to just buy a couple smaller T5 fixtures instead.