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Anyone installed 12v internal lighting?

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    #21
    Originally posted by OwlHoot View Post
    HUH?!

    How can that be? I was told they use so little electricity you could practically leave them on all the time without worrying about your electricity bill.

    I mean that's the whole point of going with 12V bulbs surely (besides the not electrocuting yourself in the bathroom thing).

    edit: Or is it that LED bulbs use vastly less than conventional bulbs (e.g. filaments & fluorescent) but there isn't much difference in eleccy usage between LEDs at 12V and LEDs at 240V ?
    It's all about the wattage. Ohms law innit.
    'CUK forum personality of 2011 - Winner - Yes really!!!!

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      #22
      Originally posted by OwlHoot View Post
      HUH?!

      How can that be? I was told they use so little electricity you could practically leave them on all the time without worrying about your electricity bill.

      I mean that's the whole point of going with 12V bulbs surely (besides the not electrocuting yourself in the bathroom thing).
      OK, let’s look at it like this:
      You pay for your electricity in kWh (that’s kilowatt hours)

      A 10 Watt LED requires 10W of power.

      Let’s put 6 of them on a circuit (just to make my maths easier in my head). That’s 60W of power.

      On a 12V circuit, you are using 60/12 = 5 amps
      On a 240V circuit, you are using 60/240 = 0.25 amps

      You’re still using 60W of power, no matter what voltage of supply you use.
      But...
      To convert 240V down to 12V requires a transformer. Transformers are not 100% efficient. Let’s say you have one running at 90%. That means you are losing 10% of power, so to get 60W to the lights, you need to put 65W in.

      240V lights = 60W
      12V lights = 65W for the same amount of light.
      …Maybe we ain’t that young anymore

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        #23
        OK here's a simple example.

        I have a four horrible ("transport cafe c. 1970") fluorescent light fittings in my kitchen ceiling, and three of the four bulbs are on the blink, literally.

        Actually I think the fittings themselves are failing, because a brand new fluorescent bulb I fitted at the weekend also didn't work.

        So I'd like to rip all these out and replace them with LED strip lights (preferably dimmable). But looking at the "LED strip light" page at https://www.ledhut.co.uk/led-strip-lights.html, already my head is spinning with the bewildering complexity of it all!

        I mean there are literally dozens and dozens of LED widgets, and I've no idea what most do or why or when they would be needed

        Also, very few of the items on that page, in fact come to think of it none that I can see, look like actual light bulbs!

        So can anyone kindly suggest the best items of LED kit from that or another LED Hut page to replace a single fluorescent light fitting with the LED equivalent fitting in the ceiling and the LED bulb of equal brightness (equivalent to say a 120W incandescent bulb) ?


        edit: Studying that LED Hut strip light page some more, it appears that what they refer to as strip lights are those silly little "Christmas tree" lights like a tape measure with illuminated patches along it. But by strip light in the above I mean a proper LED replacement for a fluorescent light (if such things exist yet).
        Last edited by OwlHoot; 9 October 2017, 16:48.
        Work in the public sector? Read the IR35 FAQ here

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          #24
          Anyone installed 12v internal lighting?

          Originally posted by northernladuk View Post
          It's all about the wattage. Ohms law innit.
          Um, no.

          Georg Ohm’s law was V=I*R (Volts = Current (amps) * Resistance)
          Wattage doesn’t come in to Ohm’s law.

          P=V*I (Power (watts) = Volts * Amps)

          ...you should have asked your accountant electrician
          …Maybe we ain’t that young anymore

          Comment


            #25
            Originally posted by OwlHoot View Post
            OK here's a simple example.

            I have a four horrible ("transport cafe c. 1970") fluorescent light fittings in my kitchen ceiling, and three of the four bulbs are on the blink, literally.

            Actually I think the fittings themselves are failing, because a brand new fluorescent bulb I fitted at the weekend also didn't work.

            So I'd like to rip all these out and replace them with LED strip lights (preferably dimmable). But looking at the "LED strip light" page at https://www.ledhut.co.uk/led-strip-lights.html, already my head is spinning with the bewildering complexity of it all!

            I mean there are literally dozens and dozens of LED widgets, and I've no idea what most do or why or when they would be needed

            Also, very few of the items on that page, in fact come to think of it none that I can see, look like actual light bulbs!

            So can anyone kindly suggest the best items of LED kit from that or another LED Hut page to replace a single fluorescent light fitting with the LED equivalent fitting in the ceiling and the LED bulb of equal brightness (equivalent to say a 120W incandescent bulb) ?
            I don’t think you really want strip lights - those are ones where you can change colours, etc.

            You could start off with something as simple as replacing your fluorescent tubes with LED tubes, e.g.
            https://www.ledhut.co.uk/t8-18-watt-...0mm-3000k.html
            (I’m not an electrician, I don’t know the size/model of your current tubes, but the above is just to give you an idea)
            …Maybe we ain’t that young anymore

            Comment


              #26
              Originally posted by WTFH View Post
              I don’t think you really want strip lights - those are ones where you can change colours, etc.

              You could start off with something as simple as replacing your fluorescent tubes with LED tubes, e.g.
              https://www.ledhut.co.uk/t8-18-watt-...0mm-3000k.html
              (I’m not an electrician, I don’t know the size/model of your current tubes, but the above is just to give you an idea)
              Yes, I was about to post that I found an LED Hut page on what they call "tube lights", and these look like the fluorescent light replacements:

              https://www.ledhut.co.uk/commercial-...be-lights.html
              Work in the public sector? Read the IR35 FAQ here

              Comment


                #27
                Originally posted by OwlHoot View Post
                Yes, I was about to post that I found an LED Hut page on what they call "tube lights", and these look like the fluorescent light replacements:

                https://www.ledhut.co.uk/commercial-...be-lights.html
                Why would you want fluorescent tubes even if they are LED in your kitchen?
                'CUK forum personality of 2011 - Winner - Yes really!!!!

                Comment


                  #28
                  Originally posted by northernladuk View Post
                  Why would you want fluorescent tubes even if they are LED in your kitchen?
                  Well it has fluorescent tubes now, and I'm not a fan of fancy, poncey spotlights that light up the ceiling and leave the rest of the room in stygian gloom.

                  Without wanting to sound facetious, I want to see clearly what I'm doing! Also, my kitchen is pretty large, about 30 by 20 feet. So a couple of normal LED bulbs probably won't cut it.

                  But I'd also like dimmable LED tube lights, in case I don't want or need the full glare, and to save more electricity.
                  Work in the public sector? Read the IR35 FAQ here

                  Comment


                    #29
                    Originally posted by WTFH View Post
                    Um, no.

                    Georg Ohm’s law was V=I*R (Volts = Current (amps) * Resistance)
                    Wattage doesn’t come in to Ohm’s law.

                    P=V*I (Power (watts) = Volts * Amps)

                    ...you should have asked your accountant electrician
                    And since it be AC wot we're talking about, the Real Power is V*I*cos(theta).

                    This is wot the old fashioned electricity meter records.

                    Feck nose what these new fangled electronic meters record, but there is much muttering about them being strikingly inaccurate.

                    <ZG in "pretending to be able to remember all this tulipe from 40 years ago and don't get me started on per unit calculations coz I never understood those to begin with" mode>

                    Comment


                      #30
                      Originally posted by zeitghost View Post
                      And since it be AC wot we're talking about, the Real Power is V*I*cos(theta).

                      This is wot the old fashioned electricity meter records.

                      Feck nose what these new fangled electronic meters record, but there is much muttering about them being strikingly inaccurate.

                      <ZG in "pretending to be able to remember all this tulipe from 40 years ago and don't get me started on per unit calculations coz I never understood those to begin with" mode>
                      Ah power factor calculations, them was the days....

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