Mounting LED Cob on a specific heatsink

Discussion in 'Hardware & DIY' started by Diogo Sousa, 11 Feb 2020.

  1. Diogo Sousa

    Diogo Sousa Member

    Joined:
    23 Jul 2017
    Messages:
    57
    Location:
    SE London
    I am looking to fix a kessil style lamp that stopped working due to overheating (careful when playing with lightning gels).

    The model is this one.

    I plan to use the gooseneck, clamp, heatsink, lens and cover. Basically only need the Cob.
    Since I am a noob when it comes to electronics and LEDs your help would be much appreciated to figure out what would work and what wouldn't.

    Ideally since I never soldered anything ever I'd get a pre-wired Cob unit but the only ones I found (Molex and Ideal) would have the mounting holes in the wrong place. My heatsink has a 30mm gap between the mounting holes.
    So my only option is to get someone to solder it for me (if you know anyone in the Netherlands let me know ;)).

    Would I be better served with a AC or DC powered LED? If I use DC can I get away with using only a 12v power supply or do I have to use a LED driver?

    Thanks in advance
     
  2. zozo

    zozo Member

    Joined:
    16 Apr 2015
    Messages:
    6,983
    Location:
    Netherlands
    Maybe this version?

    http://www.aliexpress.com/item/3290...earchweb0_0,searchweb201602_,searchweb201603_

    These can go straight to ACV 220 and don't require an extra PSU or a constant current driver, but likely require a much heavier heatsink.

    Low voltage alternative would be the 7C2B or 2B3C cob units, depending on the wattage go from DC 12 volt and up and require a constant current driver with correct mA output. And a AC/DC power supply
    http://www.aliexpress.com/item/3270...8#0#131923#18_668#808#4094#140_668#888#3325#8
     
    Last edited: 12 Feb 2020
    dw1305 likes this.
  3. Diogo Sousa

    Diogo Sousa Member

    Joined:
    23 Jul 2017
    Messages:
    57
    Location:
    SE London
    Thanks for the reply Marcel, as always!

    The factory Cob was also AC powered and used 12-16w. What makes you think the heatsink couldn't handle 9w? It is actually quite heavy and sturdy.

    What about this one? Very similar to yours but much cheaper (does that make it less reliable?) https://nl.aliexpress.com/item/4000...earchweb0_0,searchweb201602_,searchweb201603_

    How do I know if these Cobs are dimmable or not?

    And in terms of power, which wattage would be better for medium-high light?

    As I said, I don't know much at all about this subject so your help is very welcome! Learning from your wisdom as well.

    Thanks
     
  4. zozo

    zozo Member

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    Location:
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    That wasn't clear to me from the OP. :) :thumbup:

    It's trial and error when buying from China. All tho with experience you can find the most reliable vendor.

    Ask the vendor if not specified. But most AC drivin cob units are dimmable via Variac.

    Also if not specified in the product specifics, ask. Personally i skip all offers that do not. But then again even if specified i had my doubts about the results, but do not have any means to argue or disprove it. Thus again trial and error.

    Leaves me with saying "good luck'!
     
    Last edited: 14 Feb 2020
  5. Mr.Shenanagins

    Mr.Shenanagins Newly Registered

    Joined:
    20 Dec 2019
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    Location:
    South Carolina
    Chinese cobs are cheap for a reason, they are mass produced and have zero quality control because they are so cheap, easily replaceable. If it were me, I’d prefer to solder and be done. Good sites for quality cobs would be rapidled, Stevesleds, mouser, etc. that make CREE, Luxeon etc. They will have better color and reliability. I considered doing an LED build myself but the cost of what I wanted for outweighed the result I desired. Plus, I’m a novice when it comes to soldering and understanding electronics in general so I didn’t want to ruin what I paid good money for lol. Anyway hope this helps
     

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