LED bulbs in halogen fittings

fluffymuffy

We have four halogen lights in the kitchen ceiling - at 50w each I thought it would be a smart move to replace the bulbs with LED ones. I bought four LED bulbs which look the same as the halogen ones but with knobbly bits - they're 12V as are the old bulbs. Trouble is though, they don't work. They flash on for a millisecond as I switch on but that's all. Is there something else I need to make this work? I'm planning to get an electrician to sort it out but I'd like to know what the problem is.

knoxy

Many LED lights need an LED controller they are a bit tlike the transformer for the 12v halogen bulbs but different enough that you can't do a direct replacement! Whoever you bought the bulbs off should be able to advise.

AdrianW2

Are you aware that very few of the 12v LED assemblies are anywhere near as bright as a 50W halogen?

27col

LED lamps are only a watt or two in output. They will not be able to replace halogens of 50w. There are some LED's coming onto the market which are encapsulated in a plastic lens. They are much better. I have not yet seen this one of this type which will fit into a halogen lamp holder. My son has one in a torch and the light output is very good. However even this is not good enough to replace a 50w halogen. Another alternative is to get lower wattage halogens. These are available. As soon as something does become available, I will be replacing mine.

basmic

Any idea what the torch is called, or the make and model of it?

Sounds interesting.

totalsolutions

The 12v LEDs might need a current limiter. You might have blown them all in an instant.
The Leds only conduct one way, like a diode, again you might have blown them all in an instant.

12v AC or DC ?
AC they will light for an instant no current limiter blowning them all.
DC Forward or Reverse Bias connection?

Lack of light output really, stick with under cupboard fluorescent strip lights.

savemoney

I found this info

http://www.futureleds.com/EXTRA%20INFO.html

PLEASE NOTE THAT LED MR16 LAMPS WORK BEST WITH A WIRE WOUND TRANSFORMER. (Torroidal)

SOME ELECTRONIC TRANSFORMERS REQUIRE A MINIMUM LOAD TO OPERATE, USUALLY 20W, AS THESE MR16 LAMPS USE SO LITTLE ELECTRICITY, AND MOST ARE LESS THAN 3W, THE TRANSFORMER FAILS TO KICK IN AS THE MINIMUM LOAD HASN'T BEEN REACHED. YOU MAY HAVE TO PURCHASE A LED DRIVER AVAILABLE ON OUR ACCESSORIES PAGE

AdrianW2

27col wrote: »

LED lamps are only a watt or two in output. They will not be able to replace halogens of 50w. There are some LED's coming onto the market which are encapsulated in a plastic lens. They are much better. I have not yet seen this one of this type which will fit into a halogen lamp holder. My son has one in a torch and the light output is very good. However even this is not good enough to replace a 50w halogen. Another alternative is to get lower wattage halogens. These are available. As soon as something does become available, I will be replacing mine.

There are a few LEDs capable of replacing a 50W halogen. Osram announced one a couple of years ago. 5W LEDs to replace 20W halogens are quite common.

totalsolutions wrote: »

The 12v LEDs might need a current limiter. You might have blown them all in an instant.
The Leds only conduct one way, like a diode, again you might have blown them all in an instant.

Much of what you've written applies to single junctions, not packaged lamps, except that they aren't 12v. All of the packaged LED lamps I've seen have incorporated a current limiting resistor/capacitor. Of course if the 12v supply isn't 12v that doesn't work. They also include a full-wave rectifier (otherwise they'd be half-brightness) so polarity doesn't matter.

As knoxy said, the issue is with cheap'n'nasty transformers designed for a load that isn't there.

sunshinetours

We replaced all our kitchen GU10 50w halogens with 35w ones as they blew and the overall drop in light is acceptable and not massively noticeable. This to me would be the best compromise on price vs efficiency until they improve the LED and prices

If you have an area where you really need good light keep the 50W ones there but use 35W elsewhere. Under cupboard fluorescents also give a good light to work with in the kitchen as previously mentioned

jimexbox

basmic wrote: »

Any idea what the torch is called, or the make and model of it?

Sounds interesting.

Ive got a Lenser V2 professional. For the size, around 10cm, its an incredibly powerful LED torch. The build quality is fantastic, and Lenser have a pretty large range, right upto a £220 X21 monster.

27col

Yes, Lenser is the name of the torch. It is not very big and cost about £30 . Brilliant bit of kit.