On Apr 12, 2:57*pm, wrote:
On Mon, 12 Apr 2010 12:47:27 -0700, David Nebenzahl





wrote:
On 4/12/2010 3:28 AM spake thus:

I believe the LED's themselves as a component, have a service life of
around 50,000 hours. The problems with current LED's for the home is
that they have to have a regulator built into each one to take 120
volts AC and reduce it to just a few volts DC. That is very
inefficient. I am thinking that LED's for retrofits will always be a
problem. In new construction, if the building is wired with low
voltage DC for lighting circuits, I think that problem can be overcome
NOW. It would be pretty easy to set up a battery bank of AGM batteries
that would be charged by solar panels and backed up by an AC charger.

That's an interesting idea, and you may be right: this might be the wave
of the future for home lighting.

One problem with this is that low-voltage wiring loses much more power
over long runs than comparable high-voltage wiring, due to I^2R losses.
(This can be partly compensated for by using heavier conductors, but
that adds cost.) While this may not be a problem in a small, compact
house where the batteries are centrally located, it will definitely be a
problem on a large suburban "spread" where the batteries may be located
in an outbuilding. Maybe not a show-stopper, but there will definitely
be some energy losses to deal with. The homeowner may end up running
8-gauge cables over long runs.

Don't forget that these LEDs don't draw anywhere near what present
incandescents and CFL's draw. Once you eliminate the point of use
regulation, the draw is drasticallhy lower. A lot of the power
consumption for present retrofit LED's is the heat given off during
regulation. The LED's themselves barely draw anything by comparison.

I don't foresee needing long runs of 8 gauge wire in residential
applications.- Hide quoted text -

- Show quoted text -

The Leds I see advertised are 80-100 LPW, but its a Spot output. I use
cheap HD cfls of about 60 LPW for .45c each with 9 yr warranty. Ive
seen a few CFLs now at around 70 LPW. Remember incandesant are only
about 15 LPW. I cant see paying the near 100% premium price for LEDs
at this time for only a near 20% increase on LPW for a colder color
bulb, that usualy isnt outdoor rated or dimmable and with a truely
unknown life span, I would relate that to the electronics package, in
real life surges, weather extremes, vibrations, all take a toll on
electronics and only time will really tell whether they last as they
say. Either way the excessive premium does not make them a viable
option for the average home owner now. Leds are really a spot light
design, not fully illuminating like a regular bulb so in most
locations they may be the right bulb, as a general bulb. In time
competition will stop the price gouging Leds manufacturers now enjoy
from limited competition, but that is years away. I want to try a few
2 w exterior Leds as landscape units, but even these are near 25$
each! I think its going to be Cfls for awhile for me.