Halogen to LED- Transformers?

Roger le Badger · Nov 6, 2018

Hi, I was hoping for some advice on replacements for the spotlights in our kitchen.

There are currently over a dozen (!), spotlights in the kitchen- all halogen. Many of them have died now, and I’m obviously looking to replace them all with suitable LED replacements, but I’m not sure a) what the suitable equivalent will be and b) whether I will need additional transformers for the new LED’s.

Having already removed some of the old bulbs, I can see in the cavity what seems to be a transformer of some kind already in there. From the picture I managed to take, it appears to be a Kingsway KLD060S MR16 transformer (dimmable), for low voltage halogen bulbs.

Is it likely that this transformer is serving all the dozen or so lights in series, or should I expect to see other transformers in the cavity? I can’t see any other transformers in the other few holes I’ve removed the old bulbs, but having not yet removed all of the bulbs, it could be possible?

I basically would like to know if I can just swap all the old bulbs out like-for-like for new LED’s, or is there more to it than this, and I need to be calling the electrician?

I've attached the pictures I've managed to take, along with a web image of the transformer I believe is present.

Many thanks!

[ElectriciansForums.net] Halogen to LED- Transformers?

EDMOND MATOSHI · Nov 17, 2018

The starting load of the transformer is 20w so replacing halogen with LED that is rated let’s say 5w won’t work as the minimum staring load is not met. In this case you would need a minimum of 4 LED’s connected to one transformer for them to work. I personally would change them to fire rated GU 10 LEDs connected to 230v supply

Shoei · Nov 19, 2018

Important to distinguish between electronic 12V inverters and wound toroidal (or other) transformers. Electronic inverters can become unstable if the load is too small, so fitting a LED can result in flickering or premature failure of the inverter. Wound transformers typically shove out 12VAC or so regardless of load so work fine even running the lighter load of one or more LEDs.

Older 12V LEDs used to be a bit rubbish but newer ones have good light output and are a useful option to upgrade 12V halogens.

Chris_4AC · Dec 19, 2018

Thank you. Just to be sure I understood right, for someone with MR16 halogen bulbs as in the attached picture who wants to go LED, you'd recommend getting rid of the old transformer and installing a GU10 lamp holder? That seems much simpler than installing a driver for MR16 LED bulbs, indeed.

GBDamo said:
Bit of a thread resurrection but been doing a trade counter straw pole on this one and the findings are that no-one seems to know what the he'll I'm on about.

They just sell MR16 LED lamps, never had any back and don't recommend transformer replacement.

Now, the caveat is that your average trade counter staff is not always that knowledgeable but you'd expect they'd remember getting a slew of returns.

In my reactive maintenance role it doesn't really matter that the lamp might not last, typically it lasts longer than the staff, typically they last longer than the halogen they are replacing.

I can see why the domestic lot would rather replace for GU10s and it make sense.

Chris_4AC · Dec 19, 2018

Thank you. Just to be sure I understood right, for someone with MR16 halogen bulbs as in the attached picture who wants to go LED, you'd recommend getting rid of the old transformer and installing a GU10 lamp holder? That seems much simpler than installing a driver for MR16 LED bulbs, indeed.

GBDamo said:
Bit of a thread resurrection but been doing a trade counter straw pole on this one and the findings are that no-one seems to know what the he'll I'm on about.

They just sell MR16 LED lamps, never had any back and don't recommend transformer replacement.

Now, the caveat is that your average trade counter staff is not always that knowledgeable but you'd expect they'd remember getting a slew of returns.

In my reactive maintenance role it doesn't really matter that the lamp might not last, typically it lasts longer than the staff, typically they last longer than the halogen they are replacing.

I can see why the domestic lot would rather replace for GU10s and it make sense.

Shoei · Dec 19, 2018

It's largely personal preference, you can get good results using a 12V LED and a separate driver or using mains GU10. All LEDs are low voltage internally so in effect a GU10 is equivalent to an MR16 with an integrated driver.

The decision is usually made for convenience and aesthetics. It may be easier to swap out halogens with MR16 LEDs if you particularly like the light fitting, if they're hard to replace without damaging the decor or if the wiring is inaccessible.