Can I Use .99 Cent PC Fans From Newegg To Cool Each COB LED?

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newguy41410

Well-Known Member
https://www.newegg.com/CPU-Fans-Heatsinks/SubCategory/ID-574?Order=PRICE

Hey guys I built three COB LED fixtures that total 20 COB LEDs. I am using Mechatronix Heatsinks that get to about 100 degrees farenheit without a fan. Id like to add a fan to each COB LED in hopes of helping bring temps down in my grow room.

My question is if these cheap dollar to 2-dollar PC fans are good enough to use on each COB LED? I don't want to spend too much on active cooling if i don't need to.

Would appreciate any suggestions for a cheap but effective cooling solution. Would also appreciate any links to the cheapest way of powering 20 PC fans. Im pretty sure i have an extra PC power supply laying around, just not sure if it is enough to power 20 PC fans, I need to tear apart an old computer to check.

Here is a link to some cheap fans on Newegg. Will these work?
 
welight

welight

Well-Known Member
you really need a fan that has blades, tip to tip the same diameter as your cooler
Cheers
Mark
 
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ab30g

Member
Good idea, fans above will have a huge effect on temps. It will pay for itself in increased LED efficiency and life. As said above, sizing and mounting are your bigger concerns.

For 20 fans, I'd recommend finding a 12V laptop-style power supply.

Such as "12V 5A AC DC Power Supply Adapter Charger Power For Compaq 5017 5017m LCD monitor" on Newegg (sorry, can't post links yet).

Or get 5 used 12V 1A external hard drive wall-warts (the light plastic kind, not the old 1lb kind that has a transformer). Or more fans per wall-wart, depends on the amperage of your fans.

It will be a lot of wiring up, so I hope you're handy with a soldering iron. Or use butt splice connectors.

An ATX PC Power supply is overkill and inefficient at such low loads.
 
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linky

linky

Well-Known Member
I have built a few fixtures that are using vero 29's running at 100 watts each on 133mm pin heat sinks. I attached a 50mm fan to each heat sink and it the hottest point of the heat sink is 104 F.. I am using one of these to power 10 of the 12v 50mm dc fans, it pulls like 14 watts from the wall to run all 10 fans.

https://www.amazon.com/gp/product/B01E6RMASC/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1

Adding fans to your heat sinks will not lower the temp in the room, it will just help remove the heat from the heat sinks and put that heat into the room, you will need to exhaust more air or use ac.
 
linderstein

linderstein

Well-Known Member
linky said:
I have built a few fixtures that are using vero 29's running at 100 watts each on 133mm pin heat sinks. I attached a 50mm fan to each heat sink and it the hottest point of the heat sink is 104 F.. I am using one of these to power 10 of the 12v 50mm dc fans, it pulls like 14 watts from the wall to run all 10 fans.

https://www.amazon.com/gp/product/B01E6RMASC/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1

Adding fans to your heat sinks will not lower the temp in the room, it will just help remove the heat from the heat sinks and put that heat into the room, you will need to exhaust more air or use ac.
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How many amps do you each run?
 
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ab30g

Member
Ya, no way a 50mm fan is running 700mA at 12VDC, more like 70mA at 12V if its pulling 14 watts from the wall for 10. That power supply linked is overkill, but will work. Just buy a 12V laptop power supply and reduce your risk of electrocution. Or buy a 24V laptop power supply and wire up each 2 fans in series to reduce your wiring run lengths.

Cheaper yet, find an 18V laptop power supply (most are) and run each 2 fans in series. Each will get 9V. They'll run quieter (but with less cooling).

If you're going the China route for CPU coolers, get Ebay item #371876598061, US$5.11 instead of US$8 in the listing above.

But also check your local classifieds or a computer recycler. There's a listing in my area for a bunch of old CPUs with their old coolers for US$4 each. They have no use for these, so make them a deal for a bunch.
 
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linky

linky

Well-Known Member
ab30g said:
Ya, no way a 50mm fan is running 700mA at 12VDC, more like 70mA at 12V if its pulling 14 watts from the wall. That power supply linked is overkill, but will work. Just buy a 12V laptop power supply and reduce your risk of electrocution. Or buy a 24V laptop power supply and wire up each 2 fans in series to reduce your wiring run lengths.
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yep, definitely an overkill, but works great though, was only 15 bucks on amazon, used 3 of them so far, since then they upped the price a couple bucks in the past week. Yeah, the fans I used only pull a watt or so each lol
 
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VegasWinner

Well-Known Member
ab30g said:
Ya, no way a 50mm fan is running 700mA at 12VDC, more like 70mA at 12V if its pulling 14 watts from the wall for 10. That power supply linked is overkill, but will work. Just buy a 12V laptop power supply and reduce your risk of electrocution. Or buy a 24V laptop power supply and wire up each 2 fans in series to reduce your wiring run lengths.

Cheaper yet, find an 18V laptop power supply (most are) and run each 2 fans in series. Each will get 9V. They'll run quieter (but with less cooling).

If you're going the China route for CPU coolers, get Ebay item #371876598061, US$5.11 instead of US$8 in the listing above.

But also check your local classifieds or a computer recycler. There's a listing in my area for a bunch of old CPUs with their old coolers for US$4 each. They have no use for these, so make them a deal for a bunch.
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not the fan the COB. sheesh. fans run 12v maybe 100-200mA max each
 
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