I have a 2W and 3W GU10 MR16 230 volt LED spot light either side of my bed as reading lamps. Very pleased with them both from B&M Bargains.
But the beam with the 2W is even but with the 3W it's centre weighted. Still have packet for 2W states 30 degrees from memory the 3W was same but this centre weighting means the angle rating is not the same as with old tungsten lamps.
I do find buying LED lamps is like a lottery I swapped 10 CFL in the living room 8W each at 350 lumen for 2 x 1.4W and 8 x 3W at 100 lumen and 250 lumen these are far brighter than the old 8W and without removing the bulbs and reading the rating I can't work out which 2 are 1.4W.
There are a number of ways to use 3 volt LED's from a 230 vac supply and it seems it depends which method is used to how efficient the lamps are. The same for fluorescent 11W tubes have a huge variation in both real light output and lumen rating. I have a folded fluorescent reading lamp which equals most LED's for lumen per watt but my kitchen fluorescent is rather low lumen per watt.
Where LED spots are used for what spots are intended for like lighting pictures on the wall then this centre weighting makes the picture look as if some vignetting has been used which is clearly not what is wanted.
Cost is another problem I bought the 2W GU10 in a pack of 3 for £10 but when in a hurry I wanted one local lighting shop wanted £10 for one. However with local lighting shop they would demonstrate so I could aim at the floor and use my camera to compare light levels centre to edge.
If wanted for a special I would say worth the extra money to ensure correct angle but so many people put GU10 spots in completely unsuitable settings that it really does not matter if 15 degrees or 70 degrees they still look like TocH candles and mimic a planetarium.
You are right on much confusion on light output & colour with LED's. As these 2 particular lights are for over a dining room table I think I will convert them to 12 volt & use a couple of dichroic lamps, at least I know what these will turn out like.
Be careful with dichroic lamps these can cause over heating. With mains voltage we have GZ10 and GU10 the GZ10 are dichroic and the GU10 reflect the heat with the light but with the 5.3 gapped pins used in 12 volt lamps there is nothing to stop you using the wrong type. So ceiling space can over heat.
Also with 12 volt there is nothing to stop a 50W lamp from replacing a 35W lamp and overloading the power supply.
I really hate the extra low voltage lamps I know they are safer in bathrooms but so many times I have found where wrong lamps have been fitted with charred beams and floor boards and burnt out power supplies.
Also a pain when using dimmer switches where matching is required either leading or lagging.
So I would always use GU10 or GZ10 a GU10 bulb will fit a GZ10 holder but not the other way around. And you can fit Cold Cathode, LED or Quartz bulbs without having to change the power supply.
I do have some 12 volt spots in my bathroom running from a transformer (Not an electronic power supply) and in theroy I should be able to swap bulbs for any size however when I fitted some 0.58W LED's mainly just so it did not look as if all bulbs were blown they only lasted about 6 months.
I have found one outlet http://bedazzled.uk.com/12v_LED_Bulb_Replacement.htm who do LED bulbs for caravans rated 10-30 volts DC (Harsh Environment protected - withstands fluctuations and spikes). But other than that I have found no other outlet which give any voltage range for their lamps they simply say 12 volt. Nothing to say if they can run on AC with sin wave or AC with a switched mode power supply.
But with GU10 bulbs often it is stated 150 ~ 250 volt it's so simple they can be swapped from LED to Cold Cathode to Quartz without any problems.
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