I'm looking at replacing the 12V 50W halogen lights in the kitchen and
bathroom with LED.
I expect many of you have done similar.
I'd be interested in recommendations, particularly concerning:
1. Compatibility with existing halgen power units. Each halogen unit
has its own "transformer". Philips seem to claim above average
2. Brightness. Can any LED match a 50W halogen?
3. Angle of beam. I expect the halogens are very wide.
4. Colour Temperature. Both kitchen and bathroom are very white (white
celings, off-white walls). Does this imply a cold white / high K temp
is most suitable ?
5. Price: There and many very cheap units on eBay, etc. I'd rather
pay a bit more and be happy, but if you can recommend a good, cheap
source, then great. Philips seem more expensive than most.
I did think of buying a few different units to try.
Thanks in advance.
They usually won't draw enough power to keep an electronic tranformer
on. Yours are likely to be 20W-60W units - there aren't any 20W
retrofit LED MR16's because there's no way that form factor can
dissipate 20W and remain below max LED junction temperature.
I would replace with GU10 fittings (mains), dispose of the transformers,
and use GU10 LED retrofits, of which there is a much wider variety
available. Choose fittings which hold the lamp at the front face
and have a floating lampholder if you can - this enables you to fit
larger (higher power) GU10 LEDs, which are longer than conventional
If you really want to keep the MR16 fittings, you will probably
have to run at least 4 of them from a 20W transformer, or replace
the transformers with ones for 12V LEDs (which is a waste of money).
You might be able to find just the GU10 fly leads, and use those
instead of the GU5.3 fly leads in the original fittings.
For a 12V 50W halogen: Centre beam - yes, but total light output, no.
For a 240V 50W halogen (which is much less efficient): pretty close.
Halogens have more spill outside the main beam. This is often
regarded as a bad thing, but when you use downlighters for general
lighting, you are rather dependant on that spill to provide the
general lighting (which is why downlighters are a bad choice for
general lighting). When you switch to LED, you may not have anywhere
near enough spill, depending on the lamps used.
Personal choice. Your 12V halogens will have been about 2800K, or
2700K if they were long life. If the rooms are brightly lit, you
can generally go for a slightly higher colour temperature. Anything
over 3500K will probably look silly in a room lit at evenings/nights,
and doesn't work for food preparation in kitchens where you need a
significant proportion of red light to assess quality of raw meat.
[email address is not usable -- followup in the newsgroup]
Thanks for all your replies.
As I understand it, the recommended GU10 LED is:
1. Mechanically identical to the GU5.3 halogen, so drops straight into
2. Has a different connector and flylead. I see these on eBay very
3. Operates from 240VAC, ie no external switching supply needed
4. Points about:
a. colour temp.
b. beam angle.
c. reliability of different sources.
Digressing back to the GU5.3. I have in my career designed switch mode
power supplies, and I always tried to make them work down to zero
current load. I have noted zero output from some GU5.3 supplies
But LEDs don't run directly from the mains, so it would depend on the
design of the LED electronics versus the 'transformer'. And my gut feeling
is a well designed 12v SMPS might well be more efficient than something
you can cram in the base of a bulb.
*If only you'd use your powers for good instead of evil.
Dave Plowman firstname.lastname@example.org London SW
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