Adding a dimmer/ pentiometer to LED Driver

Discussion in 'The Projects Forum' started by Gregory6106, Jun 18, 2013.

  1. Gregory6106

    Thread Starter New Member

    Jun 6, 2013
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    Hello!

    So I bought some Ecoxotic Cannon 100w Pendant LED lights for my aquarium, 3 total. Each is driven by its own Meanwell PLN-100-36 driver, which I've uploaded a photo with the specs. I could have purchased drivers with built in dimmers, but I opted for the cheaper option and bought the ones without. Now I'm finding that I should have got the dimmable ones, but they are roughly $150 each. My question for you scholars of electronics is, can I just cut the wires leading from the driver to the lights and wire in a dimmer or pentiometer, (if I'm saying that word correctly?) It would probably save me a lot of money if this can be done. If so, what sort of device should I look for?

    These are expensive lights, so I really don't want to guess at this.
     
  2. Gregory6106

    Thread Starter New Member

    Jun 6, 2013
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    I meant potentiometer......I'm a noob! Sorry!
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    No. not really.

    and dimmable replacements are not $150 each (assuming thats USD)
    A meanwell LPF-90D-42 would be a similar replacement and can be had for $50
     
  4. Gregory6106

    Thread Starter New Member

    Jun 6, 2013
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    Ah, that is good to know. The dimmable driver recommended goes for 129.00. Just checked. Also, I'm finding obscure references to an internal potentiometer. Says something about being able to adjust output. Would this be the way to go? How would I go about finding this? And how can I adjust it? Meaning, is it a knob inside the device that I can just turn down while the lights are running? Or do I need to disconnect everything and use multimeter?
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    If you open the case on the meanwell there is an internal potentiometer (labeled SVR2) however it can only adjust output current down to 2 Amps... no less

    And sorry the LPF-90D-36 (36 not 42) is a better solution and a simple 100k potentiometer across the dimming leads will give 10 to 100% current adjustment.
     
  6. Gregory6106

    Thread Starter New Member

    Jun 6, 2013
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    I'm looking at the datasheet for the elliptical 100w canon and it says "Constant Current: 3.0A." I'm confused, why would I need to drop below 2?

    I understand your suggestion about the other driver. I wish it were that simple. My wife is simply not going to support me spending $150 on three new drivers. So hopefully you understand if I seem to be exhausting any and all other options. :)
     
  7. wayneh

    Expert

    Sep 9, 2010
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    You might spend some time to see if you can find something like this, but for your 36V. Or depending on how your LEDs are wired, maybe you could use that device for 12V segments of the circuit.
     
  8. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Technically the driver you posted has a max current of 2.65A (marketing/sales folks will round up to 3A as is the case here) To "dim" an LED you simply reduce the current being fed to it. And the internal potentiometer (SVR2) on that driver will only allow it to go down to 2 Amps from the default 2.65 Amps.. No lower.. Again dimming is simply reducing the current. So I assume that you wanted to do "full" dimming or something more than going down to only 2 A.. Going from only 2.65A to 2A will not be a "drastic" change in brightness and probably not dim enough for you.. But if you only want to "slightly" dim the light then the 2A is enough..but I highly doubt thats what you want.. (I too have a reef tank with DIY LED lighting and am somewhat of a nerd when it comes to LED drivers/reef tanks) but I'm far from an "electronics wiz"

    So what you want is to be able to (via a simple potentiometer) is "shunt/reduce" some of the 2.65A of current delivered by the constant current power source.
    My "non-electronics wiz" solution is to simply buy the proper drivers like the LPF series I posted above.. Of course I'm married too but I wear the pants around here :D
     
  9. Gregory6106

    Thread Starter New Member

    Jun 6, 2013
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    Actually, dimming a bit is exactly what I want to do. I'm not looking to dim to off. My gut is telling me my lights are too intense because the top third of my tank is dead barren waste land. So I was wanting to back them off a bit. So I may try adjusting the potentiometer down to 2A and see what happens. But if that does not work, the link posted by wayneh is exactly what I was visualizing when I first posted my question. So thank you both for all the help! Any tips or things I should know before I open these drivers and dial down the current? I'm assuming I won't be to accidentally turn it the wrong way and give too much current and fry the light, hopefully?
     
  10. Gregory6106

    Thread Starter New Member

    Jun 6, 2013
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    Oh, and wayneh: if I were to look into a device like you posted, what exactly am I looking for? Same thing but rated at 36V? Not sure I understand that 12V segment thing you mentioned.
     
  11. wayneh

    Expert

    Sep 9, 2010
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    Forget the segment comment - I hadn't really thought that through.

    I think you can look for DC motor controllers like this one. I haven't researched the details but at first glance it seems like it should work fine for LEDs as well as a motor. Here's another.
     
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