Which replacement transformer to buy?

[Harry Bloomfield]

The automotive LED needs smooth DC, 10 - 30 volt, and are more expensive to standard house hold types.

Not the ones I bought, it's been a few years, but they were dirt cheap and for 12v, well 12 to 15v.

 

[FrodoOne]

The photos shown in Post #5 show a 12 V 10 W Halogen G4 lamp
These lamps can be replaced with LED G4 lamps, which will provide the same illumination at a much lower wattage.
If you choose LED "lamps" which will operate on 12 V AC (because the have an inbuilt Full-Wave Rectifier)
you can use any 12 V AC 'transformer" (or DC "Power Supply") which has the capacity to supply the required current.

For a start, you might try searching on

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If you choose 12V 3 W LED lamps, you will require 0.25 A per lamp - so, 10 lamps would need a supply with the capacity of 12 V at at least 2.5A

How you mount the "transformer" and where you place it is quite another matter.

 

[bernardgreen]

you can use any 12 V AC 'transformer" (or DC "Power Supply") which has the capacity to supply the required current.

Some 12 volt AC LED lamps rely on a capacity to limit the current, these will NOT work on a 12 volt DC supply

 

[ericmark]

Some 12 volt AC LED lamps rely on a capacity to limit the current, these will NOT work on a 12 volt DC supply

I have wondered if a capacitor is used as a driver in any extra low voltage lamps? I know used a lot with low voltage, but extra low voltage tend to use resistors or PWM chips.

However

you can use any 12 V AC 'transformer"

is not quite right, as electricians we may see the difference between an "electronic transformer" and a " toroidal transformer" but the man in the street is unlikely to understand the difference, they clearly both transform the supply, but the "electronic transformer" is really a switch mode power supply, which often have a minimum output and tend to have an output in the MHz range, which will also impact on what @bernardgreen says, as the amount of current which will pass through a capacitor at 50 Hz is not the same as when in the MHz range, and I have noted some MR16 compatibles with G5.3 pins with 50 Hz written on them.

The picture shows 80 - 250 watt, 10 watt 12 volt quartz halogen bulbs, input 220 - 240 output 11.5 volt, it is clearly an electronic transformer as it has a minimum rating, and the chandelier will have at least 8 bulbs, likely 10 - 20 bulbs as one wants to allow a bulb to fail without the whole chandelier failing.

Personally I feel the minimum output should = one bulb, but that is clearly not the case here. We don't know how many bulbs, it seems 1.5 to 2 watt is the norm for a G4 LED and 10 to 20 watt for a G4 quartz, so to run LED I would expect to fit a 8 - 25 watt power supply, and really does not matter AC or DC, what does matter is physical size and how to mount it.

 

[bernardgreen]

I have wondered if a capacitor is used as a driver in any extra low voltage lamps?

A number of table lanterns rated as 12 Volt AC were planned for a reception. To avoid the need to bring wired power to each table the event manager proposed using 12 volt batteries. The lanterns did not work on the DC from the batteries.

 

[ericmark]

A number of table lanterns rated as 12 Volt AC were planned for a reception. To avoid the need to bring wired power to each table the event manager proposed using 12 volt batteries. The lanterns did not work on the DC from the batteries.

Interesting, this means neither would a DC power supply, often called drivers, and the AC supply would need to be 50 Hz, I have seen as said MR16 type bulbs marked 50 Hz, but assumed it was so a switch mode supply which would not work from zero was not used, since my lights had a massive 250 VA toroidal transformer I was not worried, but they are not small or light and can't see them being fitted inside a lamp.

After @bernardgreen post I went to look at what it said on adverts some clearly state AC/DC but others say nothing, although the picture with AC between the pins does seem to suggest AC only. Yet the use of a chip seems to point to power being rectified and smoothed. But on going to company web site a couple were marked DC only, but nothing found saying AC, and they seemed to be marketing drivers which were DC to power them.

The

video was of interest, seems LED lights do not attract insects in the same way as tungsten, which for us must be good, however they admit they don't know how they affect humans, I know my daughter has had problems with my LED lights so I swapped all the E14 bulbs for another make, I will guess on some strobe effect, but smart bulbs have some much electronics in the bulb, and clearly some large smoothing capacitors, so seem less likely to produce a strobe effect, but one is hardly likely to cram that lot found in a GU10 into a G4 bulb.

So the big question for @macbun is fit new transformer or swap whole fitting.

I have also had problems with LED and in my case the use of electronic switches, with both not switching fully off, and a shimmer when on, in my case the G9 bulb which is 230 volt, and at long last I have found an electronic switch which uses batteries for the wifi function and as a result seems to have got around the problem.

But the government is very keen for us to move to LED, but it seems not so keen to tell us how.

 

[bernardgreen]

It is possible that the lanterns used a diode pump to produce a DC voltage greater than the RMS voltage of the AC to supply several LED elements connected in series

Diode pumps depend on the supply being AC

,

 

[bernardgreen]

But the government is very keen for us to move to LED, but it seems not so keen to tell us how.

Not keen to tell us how because they have not researched the matter. They are so determined to have nothing but LED lighting ( in the domestic market ) that they have chosen to ignore the disadvantages.

There are so many reasons for keeping low wattage incandescent lamps available for some applications. The warmth from an incandescent lamp can prolong the life of lamp holders in festoon lighting by reducing moisture in the lamp holders.

 

[ericmark]

In the old house, when I went to CFL I found I needed a programmable thermostat to compensate for lack of inferred heat in the evening. But I was also rather surprised to find out how different the three houses I have lived in during the last three years have been with regard to heating.

We all tend to think of our own house, area, etc. And in the last house there was no real need for outside lights, but there is here, there was no need to have a car, there is here, the house never over heated, this one does, the list goes on, never watched red tailed kites from window in last house.

But we the home owners have now got to find a way around the withdraw of tungsten lamps. The chandelier I fitted was because the largest BA22d LED bulb did not equal the amount and spread of light we got from the old 150 watt tungsten, the 100 watt tungsten would just about light the room, but a 15 watt LED just was not good enough, so now 8 x 6 watt LED's. And that is supplemented by the display cabinet lights when required there is nearly 58 watt of lighting when those lights are turned up full, three sets of strip lights. So 106 watt with everything turned up full, OK not normally turned up full, but the fact remains the 100 watt tungsten has been replaced with 106 watt LED, how is that a saving?

The problem for most is cost, each strip light either side and there are two was £25 each, the centre strip Lidi was around another £20 the chandelier around £100 the bulbs £16 the plug in ceiling rose around £20 so over £200 to do the lighting, and now about to fit a smart switch so we can turn on lights from the chair when I nod off watching TV and the TV times out leaving me in total dark.

And I still need a standard lamp behind the chair if I want to read.

OK I can afford to do all that, but not everyone is so lucky.

 

[JohnD]

seems LED lights do not attract insects in the same way as tungsten,

That's very good news. I've noticed we get hardly any in the bedrooms now in Summer.