found another passive opton for us cob guys/ cob build thread

Discussion in 'Lighting' started by Reo, Aug 14, 2017.

  1. just got in today the artic alpine 11 passive cpu cooler. its a 95mm2 by 65mm high and is good for 47 watts... albeit not the best for some setups but for a low power setup or matched with a 92mm fan it should kick some ass.
    as for myself I will be setting up the light today/ tomorrow and later on down the road ill be making a forced air hood using 5 92mm(aprox 24 cfm but tbd on actual brand) fans per 4 heat sinks vented out a 4" flexi duct.

    if there are any questions about these heat sinks feel free to ask. the build portion will be coming soon
  2. so here is where I'm at got the sinks mounted and am going to be drill/taping for the cob mounts tonight.

    I got to say though it's a heavy piece of fram maybe 10-15 lbs minus the hood, fans and guts. I'm just hoping I can find a happy medium wire length that the driver will push. as my other remote driver setup almost isn't even worth it as I have maybe 2-1/2' of run or it wont turn on. 2' of that running from the frame to the ceiling of the tent so leaving me quite limited as to how far back I can put the light from my utility opening.

    Attached Files:

  3. how much do they cost?
  4. what gauge wire are you using? What amperage?
  5. #5 Reo, Aug 16, 2017
    Last edited: Aug 16, 2017
  6. I bud,

    I'm using 14 guage stranded wire. I think I found my problem though. See the last light I made the cobs were after the longer run on the negative side. So, my guess, by the time the voltage traveled through the negative there was that much of a voltage drop the they didn't turn on. So to prove my theory I'm setting up the lights so that the negative is the shorter run to the cobs. If it works I will be re wiring my other light as I sort of need the extra length.

    ya 14 awg 153vdc 1050ma right now as I'm combating heat issues as for my gear my driver is a mean well hlg-320h-c2100a matched to 4 vero 29 cobs(2 3000k/ 2 3500k).

    pricing pends where you are this is the place I got the artic alpine 11 passive from.Arctic Alpine 11 - Passive CPU Cooler TDP up to 35W For Intel Sockets Model ACALP00011A - show as $20 bucks usd or $15 CAD. I gave a look at those pin heat sinks that everybody raves about but to be honest fuck that. by the time I pay for a higher shipping price plus ransom fee upon delivery it really isn't worth getting stuff from the states. plus that the artic's are better suited for a vented hood design
    • Agree Agree x 1
  7. yup my theory proved correct I got a good 7' foot between the light and driver... so I guess I'm going to be re wiring my first light I made just do to the fact that 2'' from the service entry just doesn't cut it lol.

    got it going right now at low power (1050ma/36v 37.8watts per cob) they've been on for about 20 mins and the sinks warm but not hot .. I did do some more reading into the specs 47 watts is with a bit of airflow( as one would have in a pc tower) but without the air flow the sinks are rated for about 35watts tds.

    Attached Files:

  8. It doesn't matter whether the negative or the positive wire is longer. Total length of the two together determines the voltage across the cobs - they don't care which side the drop is on.

    Regardless though, 14g wire at 1050 mA has a voltage drop of only 2.65 mV per foot. Even a run of 20 feet total is only going to lose 0.05V. No way that's going to prevent you from lighting up. Far more likely there was a bad contact at some point in the string that was dropping enough volts to cause the driver to overvolt and shut down. With a series string one spot is all it takes to shut everything down. But its working now and that's what counts, right?

    I'm with ya on the pin heatsinks, they are ridiculous. I found some Dell copper heatsinks for under 5 bucks each on Ebay, but I have not tried it yet. I REALLY wish I could find a bunch more of these:

    Unfortunately they don't make them any longer.

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