12V MR16 lighting - LED??

[Lobster]

What's the current state of play with these? Having just had to replace
yet another from the array of allegedly long-life 35W tungsten MR16s
which festoon our kitchen ceiling :-( I'm interested...

eg, lots here:
<http://www.bltdirect.com/products.p...+Retrofit+Version+LED+power+supply+not+needed>

What wattage do you realistically need to replace an 35W conventional
bulb? What's the colour temperature like? Payback time? etc etc.
Anyone made the 'jump'?

Thanks
David

 

[Andrew Gabriel]

What's the current state of play with these? Having just had to replace
yet another from the array of allegedly long-life 35W tungsten MR16s
which festoon our kitchen ceiling :-( I'm interested...

eg, lots here:
<http://www.bltdirect.com/products.p...+Retrofit+Version+LED+power+supply+not+needed>

What wattage do you realistically need to replace an 35W conventional
bulb?

There isn't one. In those consumer products, the white efficiency
is not much better than the halogen lamp, so you'd need something
like a 30W one. They don't exist, because there's no way to run
an MR16 at 30W without cooking the LED. Best you can get is a few
watts, and that's the equivalent of a few watts of halogen lighting.
Efficiency and lifetime of LEDs plumets when they get warm.

What's the colour temperature like?

Cold white (5000K or so). 3000K ones are only half the efficiency,
so you won't find them in cheap consumer products.

Payback time? etc etc.
Anyone made the 'jump'?

I'm playing with Luxeon ones I've made myself. If you want to buy
ready made products containing professional quality lighting LEDs,
they seem to start at around £50 each, with most nearer £80.

 

[Lobster]

There isn't one.

Bummer. but thanks for the info.

I'm playing with Luxeon ones I've made myself. I

I came across a diy site yesterday actually: this sort of thing?:
<http://www.reuk.co.uk/How-To-Make-MR16-LED-Spotlights.htm>

David

 

[Andrew Gabriel]

Bummer. but thanks for the info.


I came across a diy site yesterday actually: this sort of thing?:
<http://www.reuk.co.uk/How-To-Make-MR16-LED-Spotlights.htm>

Not the same as that. (Can't see much point making that -- you
can buy them easily enough.)

I'm using proper Luxeon lighting LEDs (3W), not little 5mm LEDs.
Also, the MR16 lamp just isn't suitable for anything other than
decorative/toy lighting -- it's too small to dissipate the required
power without getting far too hot. There's scope for designing
replacement bulbs with the same front flange fitting, and a much
larger rear for a heatsink, which would fit in some MR16 fittings.
But I think LED retrofit is unlikely to be where LED lighting is
going to succeed, unless someone works out how to make LEDs work
efficiently very much hotter than they can today.

 

[Alan Braggins]

I'm playing with Luxeon ones I've made myself.

The newer Cree XR-E is more efficient than the Luxeons. (Not to the point
where you can equal a 35W halogen with 3W of LED, but enough that 3W of
LED may be enough for some MR-16 applications.)