RE: Dimmable LED's for CBUS

["Richard \(lists account\)" <rich_lists@xxxxxxxxxx>]

There is less off axis light with LEDs, so while directional dichrics
or
whatever halogens you have may be ok for room lighting now, the LEDs seldom
are.

=20

There are many impossible lux/beam angle/wattage claims coming out of china
on those MR16 retrofit halogens =96 like the 1 watt replacement for 35 etc.
Keep in mind they will be comparing with a crap 35 watt MR16, possibly even
a GU10 one that=92s rather orange and lousy efficacy.

=20

Cree make the chips =96 random Chinese factorys put them into housings they
usually buy from someone else, so just like ebay CCTV cameras, 2 that look
the same can be quite different performing. Half of the HongKong/Shenzhen
sellers are just people that have a stand in one of the large electronics
malls there and don=92t really know their products at all. There are some
t=
hat
do, like sure electronics and similar, but they tend to specialize and
seldom have the MR16 replacements =96 I guess they know that they are
prett=
y
much all junk.

=20

The only ones I have tried that actually dim are some line level R93 ones
that don=92t have smoothing caps in them. Since they don=92t have caps,
the=
y
flicker badly even at full brightness. They were promising some that dimmed
smoothly based on the PWM angle from the conventional mains dimmer, but IMO
duplicating many little power supplies across lampholders just so you can
drop in the lamps is a foolish economy.

=20

I expect that things will change shortly with some larger manufacturers
starting to show an interest in it, but for now all the cheap retrofits are
no way suitable as replacements for incandescent MR16=92s if you don=92t
wa=
nt to
put in more fittings. The ones that can light a room are about 5w and have
minimal directionality, and the spot ones will do an excellent job lighting
some art or pottery etc, but not to light the room. Mix and match and you
may have a solution.

=20

=20

From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf Of
Gareth Cook
Sent: Saturday, 19 December 2009 12:25 a.m.
To: ukha_d@xxxxxxx
Subject: [ukha_d] Dimmable LED's for CBUS

=20

=20=20

Anyone tried using dimmable LED's yet ? With CBUS or any other system ?=20
I'd like to remove all my dichroics so i can insulate the loft and
reduce=20
consumption.

I've heard Cree are a good brand to target - their lamp ranges from =A310
t=
o=20
=A3300 (!). What I need to understand is how to map the "quality"
of a=20
50w/35w dichroic lamp to one of their LED's They appear to be more=20
expensive, but some of them only consume 1W, despite being
"superbright".

Would we agree that we should try to map the Lumens, beam angle, and=20
"warmth" ? And then perhaps the transformers ? Most of mine are
the old=20
wire-wound toroidal transformers, so there shouldn't be a problem with=20
minimum load - only the newer electronic transformers might have to be=20
changed out for the smallest load models (ie 10w perhaps)

Here'a an ebay page with some of their range - http://tinyurl.com/yajj5sx

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number=20
741598.=20
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU

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