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What to do with LED MR-16s... can they be wired in series?

Discussion in 'Lighting and Electrics' started by TupeloTechie, Sep 7, 2017.

  1. TupeloTechie

    TupeloTechie Active Member

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    So I found 110 brand new Philips 7MR16/F36 3000 DIM AF HO lamps at a thrift store today and had to buy them for the price they were asking...

    7w, 40w-eq. LED MR-16s
    Anyone got any crazy ideas for me?

    Can these LED retrofits be wired in series of 10 to create 120v circuits like traditional MR-16s or will that mess with the internal electronics?

    They are rated for 12v AC, will running them off of 12V DC severely shorten their life? Just playing around I was able to use a DMX Decoder designed for LED tape/strip to power and dim one of the lamps, but I'm not sure if this would be recommended... would make for a couple of really awesome pixel mapped 20-Lite blinders, with one of those 24ch decoders and a beefy power supply in the case.

    Might just sell them too... who knows!
     
    Last edited: Sep 7, 2017
  2. Crisp image

    Crisp image Member

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    Are you sure they are 12V ac because they are a Light Emitting Diode they have an anode and cathode so it would be DC required to power them. A suitable transformer installed in line would convert the AC to DC. Now I could be wrong as I have not delt with these lamps but my basic electronic (diode) theory tells me that any DC supply should run them (at 12V oc course) so these lamps in my mind would have lots of uses installed in sets where a wireless solution is required and they could be powered by battery.
    My thoughts only.
    Regards
    Crispy
     
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  3. TupeloTechie

    TupeloTechie Active Member

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    They are indeed marked as 12V~ on the lamps, and it is my understanding that the ~ symbol denotes AC. The leaflet from Philips, linked below, just states 12V, so maybe there's some sort of electronic mojo inside that allows them to work with either AC or DC power? They do seem to work just fine on DC power, just want to make sure I'm not slowly frying something inside!

    http://www.assets.lighting.philips.com/is/content/PhilipsLighting/fp929000263404-pss-global
     
  4. Chris Pflieger

    Chris Pflieger Member

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    They're replacements for halogens, yes they will run on 12 VAC.

    In basic theory, yes you can wire them in a series of ten and plug them in. But, in reality no, that's very bad. They're not uniform resistive loads - each will vary in it's resistance and not in a linear way. Therefore, they won't actually see a consistent twelve volts on each one.

    MR16 fixtures are cheap, don't take short cuts.

    Oh, and yes, there's a lot of electronics between the terminals and the actual diode.
     
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  5. TupeloTechie

    TupeloTechie Active Member

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    Asking about the series wiring in reference to using these is a drop in replacement for MR-16 Mini Strips or Zip Strips, which are wired as 10, 12v lamps in series.

    Also curious as to whether a 12v AC transformer or 12v DC LED Driver would be best for powering singles, especially when it comes to dimming.
     
  6. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @Crisp image A question of correct wording / semantics: When you stated "A suitable transformer installed in line would convert the AC to DC. Now I could be wrong" You are indeed wrong. Transformers are totally AC devices: AC in on their primary winding(s), magnetically coupled via their core and AC out their secondary winding(s)
    There are wall warts and line lumps which are AC in and DC out but those would be some manner of DC power supply rather than a simple transformer.
    Toodleoo!
    Ron Hebbard.
     
  7. Crisp image

    Crisp image Member

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    Ok Ron it should have been a suitable transformer with a rectifier inbuilt. LOL
     
  8. Chris Pflieger

    Chris Pflieger Member

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    ...and filter.


    "transformer" gets misused a lot; even as much as a stickler as I am, I don't often bristle at it's misuse.


    As for the lamps in question, the spec list "Input Frequency 50 to 60 Hz", i.e. not for DC circuits. It doesn't spec dimming method, so I assume it's forward phase cut.
     
  9. BillConnerFASTC

    BillConnerFASTC Well-Known Member Premium Member

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    If they are really inexpensive, put 10 of them in a serially wired strip and try it on dimmer. If it doesn't work, seems like you might loose just one. Please report.

    These are just what I put in my kitchen in individual cans that each have a transformer in them. Just a basic or maybe above average color LED retrofit lamp.
     
  10. ship

    ship Senior Team Emeritus Premium Member

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    blew up a lot of Pin spot lamps before somewhere in the chain it stopped in trying this 120v thing. That said, I have done MR-11 Micro stipped LED recently but not in parallel.

    AC/DC is important, beyond that, try not to wire a LED in series (above reasons), a transformer even if remote will be sufficient.
     
  11. David Ashton

    David Ashton Active Member

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    yes you can wire them in series but they will blow up, they are a dc device but have a rectifier in them so work on ac/dc. Dimming may or may not work very well, steppy and drop outs.
     
  12. JonCarter

    JonCarter Active Member

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    One of the problems with seriesing such things is that the resistance of each item will not be exactly the same, therefor the voltage across each element of the series circuit will not be the same. If you build a network with appropriate resistances in parallel with each element of the series circuit you might get away with it.
     
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