decorative wall light dilemma

[Gil Williamson]

Some 10 years ago I fitted a pair of decorative wall lights. Each consists of a mains to 12 v transformer, leading to three 12v halogen G4 bulbs in shades at the ends of three curved tubes. Everything is wonderfully compact and pretty (translation - awkward, flimsy), but the transformer in one of them has conked out. Even if I could get a new transformer small enough and of the right shape, the G4 connectors in both lamps have become cranky, and I spend ages trying to get all the lamps alight simultaneously.

My bright idea is to take them off the mains circuit altogether, and when I want them on (they provide no light, just decoration, so mostly for visitors), I slip a lit battery-powered white LED into each shade (all point upwards).

However, due to the above-mentioned compactness and beauty, there's not much room in each shade, so I'm looking for the tiniest battery/LED combination that'll give enough light to demonstrate that they are illuminated. Ideas?

 

[SparkyChick]

Hi Gil,

I have found that the LED G4 capsule lamps are quite good, and have had some success with 'cranky' holders that wouldn't take halogen bulbs working quite well with LEDs (after a liberal dose of contact cleaner) due to the vastly reduced currents involved (poor contacts usually result in a higher than average contact resistance that will cause more problems for high powered lights).

As for the transformers, there are lots available so sourcing one of an appropriate size (particularly given the vastly reduced power requirements of LEDs) shouldn't be a problem.

Hope that helps.

 

[Gil Williamson]

Thanks for the reply. Using a low-power LED capsule lamp sounds a good option for the cranky contacts. I'll give that a try with the still-viable lamp.

The failed transformer is the shape of a doughnut 40mm across and about 10mm thick. I hadn't expected to find one that shape/size, so hadn't looked.

As to my all-battery solution, I'm sure I've seen tea light format lamp/battery combinations, and I hoped for some solution based on that.

 

[Wilko]

Hi - you could perhaps move the transformer out and only take the extra low voltage into the lamp(?). Any chance of a pic?

 

[Gil Williamson]

Not very practical to re-site the transformer. I'll take a pic tomorrow, but basically it's an unblemished wall. The mains supply comes out of the wall under the circular domed fitting. I'd have to dig a hole in the wall big enough to carry the txfrmr, but small enough to be concealed by the 6" diameter fitting. There's nowhere else between the switch and the lamp where I could place the transformer.

 

[SJD]

Aurora make a range of round lighting transformers designed for decorative lights with G4 capsule lamps, but I think the smallest size is a bit bigger than 40mm. If there is any identification on the transformer, try searching online for one.

 

[Shoei]

Thanks for the reply. Using a low-power LED capsule lamp sounds a good option for the cranky contacts. I'll give that a try with the still-viable lamp.

The failed transformer is the shape of a doughnut 40mm across and about 10mm thick. I hadn't expected to find one that shape/size, so hadn't looked.

As to my all-battery solution, I'm sure I've seen tea light format lamp/battery combinations, and I hoped for some solution based on that.

That is very small, the smallest ones that are readily available are 55 x 22mm. Like this one for example. Are you sure it's only 10mm?

 

[Wilko]

Here's another small LED driver, just for ideas
Universal LED DRIVER 3W 350mA external LED power supply IP66 constant current | Liminaires - https://www.liminaires.co.uk/ad401327-universal-led-driver-3w-350ma-external-led-power-supply-ip66-constant-current.html

 

[Gil Williamson]

Guys, thank you. I confess I had no idea transformers could be so small. But, of course, I was originally thinking in terms of powering three 15w halogen lamps. I think with a bit of digging into the plaster, I might be able to accommodate one of these LED transformers supplying three 1-2w capsule LEDs.

It's Chinese-made. The transformer in place purports to be an Anchorn AET 3202CL, but the photographs of the 3202 on the web look different from this one, and the depth measurement is 16mm, whereas the official 3202CL quotes 25mm. I have a feeling it may be an older version or a counterfeit. In either event, 25mm wouldn't fit.

I made a mistake when I said in a previous post that the current transformer was 40mm diameter - it's 40mm radius, 80mm diameter.

 

[telectrix]

you could always get a plumber to re-install the pipework for gas lights.

 

[Gil Williamson]

Yeah... or just hang a picture over the blemish in the wall. However, I'm going to keep trying.

In surveying LED capsule G4 lamps, I found a warning that 12v as usually supplied to halogen lamps was not true DC, and that some (all?) LED capsule G4 lamps would not work. What's the truth of this? And I don't need them to be dimmable - should this affect my choice?

 

[telectrix]

Yeah... or just hang a picture over the blemish in the wall. However, I'm going to keep trying.

In surveying LED capsule G4 lamps, I found a warning that 12v as usually supplied to halogen lamps was not true DC, and that some (all?) LED capsule G4 lamps would not work. What's the truth of this? And I don't need them to be dimmable - should this affect my choice?

depends on the G4. some work on d.c. only. some will work on a.c. i have a fitting in the hall here, 9 G4 lamps replacing halogens and it works OK on a.c. left 1 halogen in to eliminate flickering, but that will be replaced once i have a few more \leds in stock. they're at present en route in the China Sea.

 

[Gil Williamson]

That's a great lamp. Where did you get it?

If they work on AC, do they usually work on both?

Flicker? Where does that arise? How will the new LEDs fix that?

 

[Shoei]

Yeah... or just hang a picture over the blemish in the wall. However, I'm going to keep trying.

In surveying LED capsule G4 lamps, I found a warning that 12v as usually supplied to halogen lamps was not true DC, and that some (all?) LED capsule G4 lamps would not work. What's the truth of this? And I don't need them to be dimmable - should this affect my choice?

Halogens work fine on both AC and DC 12V and the transformers usually provide an accurate voltage. The only proviso is that LED's may present too small a load for an electronic inverter to work correctly. Electronic drivers usually have a min-max range and taking too little power may make them unstable.
If your LED takes power in the specified range of the driver it will work, they don't need DC and will work over a much wider voltage range than halogens. They should be fine.

 

[telectrix]

That's a great lamp. Where did you get it?

If they work on AC, do they usually work on both?

Flicker? Where does that arise? How will the new LEDs fix that?

got it from a car boot sale £4. the halogen was left in to give the transformer a bit more load in case it was working below it's minimum load level.

 

[Gil Williamson]

got it from a car boot sale £4.

Great bargain. Looks like a £200 fitting.

Thanks.

 

[Gil Williamson]

got it from a car boot sale £4.

Great bargain. Looks like a £200 fitting.

Thanks for the advice..

 

[Gil Williamson]

If your LED takes power in the specified range of the driver it will work, they don't need DC and will work over a much wider voltage range than halogens. They should be fine.

Reassuring! I'll get moving on this.

Needless to say, there's another hitch. With the halogens, the way to change the bulb was to unscrew the shade, insert the bulb, then thread the shade over the bulb (9mm) and screw it back. I can't find a capsule LED thinner than 10mm, so I'll have to screw the shade on first, and insert the bulb through the shade. Fingers and pliers won't reach. I'll have to improvise a tool to insert the bulb. At least with LEDs , I shouldn't have to do it very often!

 

[Shoei]

Reassuring! I'll get moving on this.

Needless to say, there's another hitch. With the halogens, the way to change the bulb was to unscrew the shade, insert the bulb, then thread the shade over the bulb (9mm) and screw it back. I can't find a capsule LED thinner than 10mm, so I'll have to screw the shade on first, and insert the bulb through the shade. Fingers and pliers won't reach. I'll have to improvise a tool to insert the bulb. At least with LEDs , I shouldn't have to do it very often!

A tool, maybe a thin tube should do the trick. If you haven't yet sourced the G4s these may be worth checking out. I used these in a very similar application, 3 LEDs on a lamp, it originally had a circular driver very like yours but that didn't work well at low load so I switched to an LED driver.
They claim 8mm in diameter but that's optimistic, the one I have in front of me will just about go through a 9mm gap.

 

[Gil Williamson]

A tool, maybe a thin tube should do the trick. If you haven't yet sourced the G4s these may be worth checking out. I used these in a very similar application, 3 LEDs on a lamp, it originally had a circular driver very like yours but that didn't work well at low load so I switched to an LED driver.
They claim 8mm in diameter but that's optimistic, the one I have in front of me will just about go through a 9mm gap.