1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

LED replacement bulbs too dim

Discussion in 'Electrics UK' started by VictorDelta, 25 Jan 2017.

  1. VictorDelta

    VictorDelta

    Joined:
    18 Aug 2008
    Messages:
    74
    Thanks Received:
    0
    Location:
    Dorset
    Country:
    United Kingdom
    In our kitchen we have 8 concealed down-lighters in the ceiling – each with a Reflekto 185051 clear 36degree 2700K 12v 50watt halogen bulb (which are 45mm long). I am keen to replace these with an LED equivalent – but one which hopefully gives a light which is as similar to what exists as possible.

    I asked several retailers for advice on this and the general suggestion was to go for Integral MR16 GU5.3 8W (50W) 2700K 680lm Non-Dimmable Lamps. They are slightly longer but only by 3mm which isn't a problem.

    Bought a pack today and tried them. They worked without flicker so there was no problem in that sense. However, they were noticeable dimmer (say, by 10-20%) than the existing halogen bulbs and, to my eye, had a rather yellower light.

    Can anyone suggest a better equivalent LED please?

    Many thanks.
     
  2. Sponsored Links
  3. Iamchamps

    Iamchamps

    Joined:
    24 Sep 2016
    Messages:
    1,035
    Thanks Received:
    162
    Country:
    United Kingdom
    There are so many your best bet is to buy 1 from some where like screw fix, test and return etc for another until your happy. The higher the K rating the whiter the light, the higher the lumen the brighter the light. 2700k (also known as warm white) is very yellow my kitchen lights are 4000k (also known as cool white). For a kitchen that is probably what you want to aim for.

    I have these http://www.screwfix.com/p/lap-mr16-led-lamp-gu5-3-345lm-5w/3474p maybe not bright enough for you at 345 lumen
     
  4. ColJack

    ColJack

    Joined:
    16 Feb 2007
    Messages:
    11,795
    Thanks Received:
    410
    Location:
    West Midlands
    Country:
    United Kingdom
    Could be the beam angle?
    Are the replacement ones reflector type?
     
  5. VictorDelta

    VictorDelta

    Joined:
    18 Aug 2008
    Messages:
    74
    Thanks Received:
    0
    Location:
    Dorset
    Country:
    United Kingdom
  6. aptsys

    aptsys

    Joined:
    16 Sep 2007
    Messages:
    1,824
    Thanks Received:
    144
    Location:
    Cambridgeshire
    Country:
    United Kingdom
    Those lamps should be more than adequate - I wonder if your previous halogen transformers aren't stable with 8W loads. Do you know if you have magnetic transformers or electronic drivers for the MR16 lamps?
     
  7. ericmark

    ericmark

    Joined:
    27 Jan 2008
    Messages:
    17,578
    Thanks Received:
    1,637
    Location:
    Llanfair Caereinion, Nr Welshpool
    Country:
    United Kingdom
    It seems typical output for a 50W GU5.3 MR16 is 500 lumen at 8W with LED the output is between 500 and 800 lumen around 70 lumen per watt is average so 560 lumen is average. However MR16 means the light is spread over a 1963 mm² or 50 mm diameter where the LED lamps don't use the whole area of the lamp, in other words they are equivalent to MR16 not a true MR16.

    Where the light is aimed at a white surface which then spreads the light, then the diameter of the source does not matter, however if aimed at a surface which will absorb the light then although the lamp is giving out the light, it's not getting into the room, place a diffuser in front of the LED's then you get the spread required, lamps like this [​IMG] work well as the light goes through a diffuser.

    The MR16 is a spot light and where used as designed the replacement LED works well, I have a pair of MR16's in the bed room aimed at the wall next to a dark corner it was easier than running cables to that corner, it works well. I also have a pair either side of the bed again able to be directed. As an experiment I aimed them at the ceiling, and used my DSLR camera to monitor the light in the room, they worked well, but same lamps aimed at the floor and results were very poor.

    It could be the power supply does not match the lamps, I noted the MR5.3 lamps in bathroom are clearly marked 50 Hz, in other words not suitable for an electronic transformer, but more likely the LED light source is more concentrated than the tungsten so it needs either a diffuser or reflected from a white surface.

    I think the 50mm or 16/8ths of an inch MR16 lamp is very good at producing an ambience and sending light to dark corners, and pictures, however they have always been useless for general lighting. Size does matter.
     
  8. VictorDelta

    VictorDelta

    Joined:
    18 Aug 2008
    Messages:
    74
    Thanks Received:
    0
    Location:
    Dorset
    Country:
    United Kingdom
    Not absolutely sure but they were installed about 8 years ago so think they are probably traditional transformers.
     
  9. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,783
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    Almost certainly they are not. The chance of them being magnetic transformers is probably on a par with Empress Treeza standing up in Parliament and saying "You know what? Having thought about it a bit more I've decided not to trigger Article 50".
     
  10. Sponsored Links
  11. Iggifer

    Iggifer

    Joined:
    8 Sep 2011
    Messages:
    4,637
    Thanks Received:
    587
    Location:
    Warwickshire
    Country:
    United Kingdom
    8 years ago could have been either.

    A 50w halogen 12v lamp will give you in the region of 700-800 lumens (according to google). So you are a little on the shy side. You'll struggle to get anywhere near the 700-800 lumens in a retrofit LED. There may be some integrated fittings that bright but they tend to top out around 600 (which IMO is plenty bright enough)
     
  12. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,783
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    So in 2006/7 there was still a significant number of ELV lighting products using magnetic transformers being sold vs SMPSUs?

    Gut feel really does say "no way"....
     
  13. VictorDelta

    VictorDelta

    Joined:
    18 Aug 2008
    Messages:
    74
    Thanks Received:
    0
    Location:
    Dorset
    Country:
    United Kingdom
    Having tried virtually all the MR16 LED options from screwfix and Tool Station, I finally found a Sylvania LED 7.5w 3000k 460lm, with internal reflector, that is bright and a pretty good match with my halogens - and would be totally acceptable if it didn't flicker! Arrrgh!

    So, now I know what I'm looking for, I might try a few other similar looking bulbs in case I find one that doesn't suffer from the flicker problem.

    Or... am I wasting my time? Given the above, would I be better off starting from scratch and installing new down-lighters - perhaps with GU10 LEDs, of which there seems to be a wider range available in the shops than the GU5.3/MR16 type?
     
  14. bernardgreen

    bernardgreen

    Joined:
    3 Nov 2006
    Messages:
    24,820
    Thanks Received:
    2,444
    Location:
    Bedfordshire
    Country:
    United Kingdom
  15. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,783
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    Yes.

    Large ones, actually designed to light up rooms.

    Not ones the size of torches actually designed to not light up rooms.
     
  16. ericmark

    ericmark

    Joined:
    27 Jan 2008
    Messages:
    17,578
    Thanks Received:
    1,637
    Location:
    Llanfair Caereinion, Nr Welshpool
    Country:
    United Kingdom
    Likely flicker is caused as the switch mode power supply switches off due to under current, then back on again. Most G5.3 MR16 LED lamps state 50Hz, I don't think the 50 Hz is that important but switch mode power supplies don't give out power at 50 Hz so it in real terms says "If not a magnetic transformer our LED's will not work."
    It is common to find an electronic transformer which is really a switch mode power supply rated 35 - 105 VA, VA is in real terms another name for watts, so if the transformer is marked 35 - 105 VA you can't expect it to work with just an 8 or 16 watt load. Some are marked 0 - 105 VA they would be likely OK. This toroidal transformer is what you should use but when you see the price you realise why people are fitting GU10 lamps.
     
  17. VictorDelta

    VictorDelta

    Joined:
    18 Aug 2008
    Messages:
    74
    Thanks Received:
    0
    Location:
    Dorset
    Country:
    United Kingdom
    Thought I should conclude this thread by saying what the outcome was. After seemingly trying every MR16 LED available, I finally found that these were an excellent substitute www.screwfix.com/p/lap-mr16-led-lamps-gu5-3-345lm-4-5w-5-pack/6917p (and only just over £2 each!).

    They may only be rated as 345 lumens (35w equivalent) but they were a closer visual match to my 50w halogens than the 50w equivalent LEDs I tried. And they didn't flicker - except in the case of one unit where the flickering started after a minute or so. Anyway, I have left a halogen bulb in that one unit to overcome the problem.

    Overall very pleased and have reduced my kitchen energy consumption considerably. Thanks for all the responses above.
     
Loading...

Share This Page