Replacing Halogen bulbs -do I need to replace the transformers too? Or upgrade to LED

Discussion in 'Home Cinema Buying & Building' started by vns, Aug 21, 2013.

  1. vns

    vns
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    Hi,

    I had my house done up 15-20 years ago, we had halogen bulbs put in.
    Now I've noticed more and more, the light bulbs are blowing out quicker.

    My initial thoughts were it's the bulbs, but I've been using quality (OSRAM) bulbs.

    Now I think I need to do one of two things:
    1) Replace the transformers and bulbs
    2) Replace the transformers for an LED lighting system

    Does anyone have thoughts on this?

    I understand that LED bulbs have higher one-off costs but running costs should be much lower...

    Many thanks in advance!
    VNS
     
  2. lindzap

    lindzap
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    I recently replaced all ten of the halogen spotlamps in my kitchen with an LED equivalent. It's expensive but the saving is there alright when you look at the bulb life. If they turn out to be true I won't be buying or replacing bulbs again in this house. There are also some really fantastic offers out there and great products. As they are expensive I bought a couple of different types to try first. I realised quite quickly that I should go for a warm colour temperature as most of my kitchen is warm colours (terracota, light oak) but the choice is staggering and you can more or less get any combo or colour, spread and fitting. One or two of them look a bitnaff - a bit like having a torch stuck in your ceiling but the ones with many different bulbs and a nice filter are just as good looking as halogens IMO. Have fun, nice little project.
     
  3. vns

    vns
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    Thanks for the info :thumbsup:, do you know what brands you bought? Or links to their websites?

    I know I definitely want some warm colours - hate cold lights.

    Only other problem I've had with LEDs is that the cone of light has a much smaller angle that it covers. Now my current spot lights are quite spread out as they are, so I need to be wary of that issue.

    VNS
     
  4. MIKEVO

    MIKEVO
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    Your best bet is to go to an Electrical Wholesaler and have a look at their product range.
    They will advise you on light levels, light spread, colour options, its worth doing some research and shop around.

    Some led Spotlights/Downlights are also dimmable, but cost more.

    It's unlikely the transformers are blowing your Halogen bulbs, maybe they are getting too hot due to summertime, or have you had extra insulation in your loft ?

    Anyway LED is the way to go, they use less power, last longer and produce very little wasted heat.
     
  5. vns

    vns
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    Yup, planning on heading over to the electrical store this weekend, thought I should ask for some pitfalls first on here before I get the sales talk...;)
     
  6. Rodders53

    Rodders53
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    It may be poor electrical contacts - the pins can overheat and damage the glass to metal seals and so lead to premature failure.
    It may also be inadequate ventilation if in-ceiling fittings causing overheating.
    Finally the transformers could - especially if under-loaded be outputting a higher voltage than the nominal 12V ac so leading to premature lamp failure.
    LEDs are improving and can match brightness but beware of colorimetry issues... They can often give an odd effect cf tungsten lamps. LEDs are dc so ideally will need a voltage regulating rectifier circuit built in to work best with existing transformers.
     
  7. lindzap

    lindzap
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    I ended up buying Toshiba, but I looked at philips and one other I forget. Lightbulbsdirect and thelightbulbcompany (both web retailers) worked well for me.

    You can buy a variety off spreads do you don't end up with a kitchen that has pools of light like a disco. That was one of the tests I did.
     
  8. supraTTman

    supraTTman
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    Good advice from Rodders except that most MR11/MR16 LED lamps have a built-in full wave rectifier so that they can work with the popular (cheapo white box) AC 12V supplies and DC 12V supplies. Maybe Del Boy found some that are the exception to this. :D
     
  9. vns

    vns
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    Had to Google "built-in full wave rectifier" - I know what you're talking about now, just didn't know the technical name.

    Also, your link seems to be broken - maybe AVF's affiliate system broke it?

    Once again, thanks for all your advice
     
  10. MIKEVO

    MIKEVO
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    You can buy new Led fittings that work from mains voltage via in built constant current power supplies that are very efficient.

    Or you can buy led fittings that effectively run in series from a single dedicated constant current power supply (maybe 10 fittings at a time), which will also be efficient.

    If your old transformers and are 15 to 20 years old, its time to upgrade and replace with modern equipment that produce less heat and are much more efficient (they tend to use high frequency switch mode power supplies than transformers)

    A full wave rectifier will give a fairly smooth DC output which has no current regulation and your leds will explode, unless current regulation specific to the LED fitting is incorporated in the inbuilt circuitry.

    Seek advice from your electrical wholesaler and get an electrician to either install the fittings or check your work before you turn the power on.
     
  11. supraTTman

    supraTTman
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    http://www.avforums.com/forums/dab-digital-radio-fm-radio/1330696-led-lights-interferes-dab-signal-2.html
    The link was one of those annoying Skimlinks automatically added and are seldom useful.

    I think MIKEVO is under-estimating the complexity of modern 12V MR16 LED lamps. In the photo, the 2 wires go to the MR16 pins, between the 2 wires are the bank of 4 diodes (full wave) so that the lamp can run off AC or DC. The IC is a buck switching regulator running at 27 KHz, the 3 tall items are switching inductor & 2 smoothing capacitors, all of which run fairly hot - even with the glass broken! The other components define and limit the current through the 60 LED's on this Lustrumlight MR16 lamp.

    Multi-LED lamps do have the advantage of wide beam angle (120 deg) as the devices are close to the surface.

    The more elegant high power LED's (e.g. 3 x 2W) sink the devices well down into the housing and this narrows the beam to 45 deg typically.

    As has been said, shop around and make sure you buy from a supplier that accepts returns because you will need to experiment. It does sound like that you need to fit all new modern transformers which will run cooler - just take note of minimum ratings (on the dimmer and transformer) if you don't go for the Varilight transformer.

    Photo originally discussed on post#54 of this DAB thread.
     

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    Last edited: Aug 23, 2013

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