Replacing with LEDs

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Tried reading through various topics on this but still confused. Hope you can assist please.

Have a few downlights in the house. These are ELV MR16 halogen type and are driven by bog standard transformers rated accordingly [Some are rated 20W and some 35W and driven by 60W//105W transformers]

Clearly LED ratings are different (in the specified wattage for each LED lamp)

What I am wondering whether the MR16 LED lamps are a straight swap for the halogen lamps I currently have and would the transformers I have still run the LEDs?

Sorry if I haven't explained this very well but I know someone out there can help me.

Thanks in advance.

B
 
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The first thing to check is whether your transformers real transformers (big heavy units) or electronic transformers (light compact unit)
 
Thanks RF

It appears I have both types. The upstairs has the big heavy ones and the downstairs the small light ones.

B
 
You'll certainly have to replace the electronic ones with proper LED drivers. You might get away with leaving the big old ones in place.

Personally I would ditch the transformers altogether and replace them with GU10 lamp holders and use mains LEDs. Look for between a 5W to 9W lamp in warm white.
 
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In theroy you can use transformers but with the lighter switch mode power supplies many have a minimum output which the LED is unlikely to draw. There are some claims but manufacturers that their lamps will work with switch mode power supplies but this thread says how in practice it does not work.

Any sin wave AC supply will peak to around 17 volt and I found the cheap 12 volt LED lamps I bought failed after a month or two so would assume they were unable to take the 17 volt peak. Clearly the lamps must have a rectifier built in as it does not matter which way around the bulb is plugged in but when I hunted for voltage limits with idea of using in a caravan which again could have 16 volt on the 12 volt supply I could find no information as to the voltage they will run on.

The 230 volt GU10 lamps do give voltage range typical 150 - 250 volt clearly some built in voltage regulation.

Using a switch mode power supply you really have no idea of the peak voltage RMS may be 12 volt but peak could be well over this. So in real terms the only safe way is to use a DC power supply.

There seems to be a lot of miss labelling in the lighting industry a driver should control current where a power supply would normally be voltage controlled but it seems power supplies are often called drivers.

In the main the MR16 LED has built in drivers which control the current to each LED and just required 12 volt DC supply so one has to read the label carefully to ensure it is a 12 volt power supply rather than a constant current driver.

I have been rather surprised with the GU10 LED's I bought. Using them in reading lamps I wanted something cool to touch but they are close to the book so did not need super high power so bought some 2W bulbs £7 for pack of three. The idea was they would not be bright enough to disturb each other when reading in bed.

However they are far brighter than expected and really light up the room. However my son fitted 7W lamps in the kitchen 5 of them and I needed to use a cycle torch to read the central heating boiler display. I am not convinced his 7W lamps are any brighter than my 2W lamps.

I have one odd 3W lamp and using the camera to measure the light output the centre of the 3W is one stop higher than the 2W but move away from the centre and they are both the same.

The 2W has three LEDs and the 3W a single LED and the spread is far better with the 2W version. I use a single 2W GU10 in my shed and I have no problems reading which bottle has what beer in it.

I think the problem is the spread of light and using spots for general lighting does require the light to be reflected off walls or ceiling which is a light colour if there is nothing for the light to be reflected from then a 2W wide angle lamps can seem to give out more light than a 7W narrow beam.
 
Tried reading through various topics on this but still confused. Hope you can assist please.

Have a few downlights in the house. These are ELV MR16 halogen type and are driven by bog standard transformers rated accordingly [Some are rated 20W and some 35W and driven by 60W//105W transformers]

Clearly LED ratings are different (in the specified wattage for each LED lamp)

What I am wondering whether the MR16 LED lamps are a straight swap for the halogen lamps I currently have and would the transformers I have still run the LEDs?

Sorry if I haven't explained this very well but I know someone out there can help me.

Thanks in advance.

B
you have to get leading egde drivers .. or you could swap out the lan=mp holders for GU10 and have them mains powered
 
you have to get leading egde drivers .. or you could swap out the lan=mp holders for GU10 and have them mains powered
Not sure how leading or trialling edge makes any difference to the maximum voltage or if the switch mode system can run with low current output.

On this page you see power supplies listed as 0 - 50W and 20W - 60W in theroy the 0 - 50W should work with LED and the 20W to 60W would not work as the LED may not be drawing enough current.

I note "Output voltage 11,5V max. 4,3A" it does not state if DC or AC or if RMS voltage.

The technical pdf is clearly for the 20W - 60W type as it refers to minimum loading it clearly states for quartz halogen bulbs.

The 12 volt LED bulb could have a simple rectifier to allow bulbs to be inserted either way and a resistor to limit the current. Or it could have a switched mode controller. There is nothing to tell us what system is used so we have no idea if it requires a 12 volt maximum or a 24 volt maximum or any other details about the bulb it simply says 12 volt.

So you may buy one make which works A1 and another may need a smooth 12 volt DC supply.

I found to my cost with CFL buying expensive well known makes does not mean they are good lamps. I got 18 x 8W Philips when these started to fail my wife got 6 x 8W of unknown make very cheap and the cheap ones were brighter and are still going and the expensive ones have all failed. It's all down to luck.

With a bulb costing 20p I was not worried but with bulbs costing £10 each it's a very different story. There are two ways to ensure the bulb is correctly supplied. One is buy the power supply recommended by bulb manufacturer i.e. same make and the other is to use GU10 where it's a standard 230 volt supply. The latter is the easy method.

Very few shops have demonstrations of bulbs you buy purely by description. As I have said I have two types of GU10 bulbs one 2W and one 3W and the two watt with three LED's gives an even light over the area lit. Where the 3W has two areas the centre is much brighter but the edges are the same as the 2W version so the 2W actually works better than the 3W.

The whole LED lighting system seems full of problems my sons house has 2 x 7W LED bulbs in living room which are ample for whole room. The kitchen has 5 x 7W GU10 spots and looks like a planetarium.

My house we replaced the fittings to take 5 bulbs each so 10 bulbs in the living room. We used 8W CFL globe type and the room was dark. We swapped to 2 x 1.4W and 8 x 3W at 100lm and 250lm in theroy 2/3rds of the lumen from the 8W lamps but the room is much brighter. Also I find it hard to work out which were the 2 original 1.4W bulbs.

I bought the bulbs from Lidi when on offer and first 2 were all that was left and second 8 were all that was left and it was pure luck that they were bright enough as if I had looked at the lumen I would have considered them not bright enough. Yet if anything they are too bright.

The old tungsten bulbs I use to keep my pets warm. I have yeast as pets and they work for me producing beer and they work so hard I think they deserve to be kept warm.
 
Thanks to all for the comprehensive replies.

I now have a better idea of what I am 'up against'.

I see that GU10 (mains) would be the way to go but that would involve a significant amount of work in re-wiring as most of the wiring to each lampholder is in the ceilings and is not of a suitable cable type for mains.

I suppose I am left with swapping out the current transformers (apologies if that is an incorrect term) for LED suitable ones or retaining the current halogen lamp set-up.

Aside from the obvious saving in energy bills and consumables, LEDs appear to give a 'better' light hence the original question.

I wonder if replacement halogen lamps will go the way of the tungstens and become extinct in due course?

Many thanks again.

B
 
It's worth noting that there are 12V LEDS available in various formats (MR16 etc.) that have internal regulation & drivers and will happily run on any supply between 11 and 30V. They are designed for use in boats, etc where they are powered directly from the service batteries that may be being float charged from either the engine or shore power.


http://bedazzled.uk.com/12v_LED_Bulb_Replacement.htm
 
It's worth noting that there are 12V LEDS available in various formats (MR16 etc.) that have internal regulation & drivers and will happily run on any supply between 11 and 30V. They are designed for use in boats, etc where they are powered directly from the service batteries that may be being float charged from either the engine or shore power.


http://bedazzled.uk.com/12v_LED_Bulb_Replacement.htm
Thanks I was looking for some good ones for my caravan. And yes I would not worry about powering those from a AC transformer as long as within minimum rating.
 

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