"Saab C900 Viggenist" <c900@[EMAIL PROTECTED]
> wrote in message
news:fus85q$hpp$3@[EMAIL PROTECTED]
> "Trevor Wilson" <trevor@[EMAIL PROTECTED]
> writes:
>
>
>>"Athol" <athol_SPIT_SPAM@[EMAIL PROTECTED]
> wrote in message
>>news:1209088115.373965@[EMAIL PROTECTED]
>>> In aus.cars Trevor Wilson <trevor@[EMAIL PROTECTED]
> wrote:
>>>> "Saab C900 Viggenist" <c900@[EMAIL PROTECTED]
> wrote:
>>>
>>>>> and there are numerous ways to
>>>>> arrange the light output from an array of LED's to make them give
the
>>>>> same
>>>>> or better distribution/spread/whatever compared to using
>>>>> grossly-inefficient
>>>>> filament lamps.
>>>
>>>> **That would depend on the incandescnt and the LED. Howeer, if you
want
>>>> REAL
>>>> efficiency, dump LEDs and use decent discharge lamps. Those puppies
are
>>>> seriously efficient.
>>>
>>> None of these LED assemblies that replace a conventional globe comply
>>> with
>>> the ADRs, ECE (European) or DOT (USA) regulations. In all cases, the
>>> light
>>> source is intended to be a filament, the position of which is
carefully
>>> defined within the globe relative to the mounting base.
>>>
>>> The lamp assembly is designed around the defined light source, ie
light
>>> emanating from a filament within a carefully defined envelope inside
the
>>> assembly. Fit something other than the correct model of globe and the
>>> lamp
>>> assembly is assumed to not comply with the relevant regulations unless
>>> the
>>> modified assembly (ie fitted with LED assembly = modified) is tested
to
>>> the
>>> standard again.
>>>
>>> Similarly, placing discharge (HID) bulbs into housings intended for
>>> halogen
>>> globes will not comply. The light source will not be emanating from
the
>>> correct position to be correctly focussed by the reflector and lens.
>
>>**None of which I dispute. What I do dispute is the claim that LEDs are
>>automatically far more efficient than incandescents.
>
> In terms of light output against total power consumption, they are
streets
> ahead.
**Not necessarily. Only when you look at the premium products, like Cree
or
Luxeon.
LED's have always been very highly efficient light emitters,
> converting almost all of the electrical energy they consume into
photons.
**Absolute and complete bollocks. I still have a handful of the first LEDs
easily available on the Australian market. I don't have the figures, but I
guess they are rated at around 0.1 millicandela. A typical, cheap, high
output LED is rated for about 10,000 mCd. Even at 10,000mCd, those LEDs
are
way behind Cree and Luxeons. Figure on it being around 1% efficient. IOW:
1%
of electrical energy is converted to light. The rest is converted to heat.
> Filament lamps, by comparison, are extremely inefficient, with
efficiences
> well under 50 percent and in most cases, it's no better than 20 to 30
> percent. That's why filament lamps produce so much heat.
**Wrong. Incandescents are VASTLY less efficient than 50%. Maybe 0.1% - 1%
efficient.
>
> The issue has been creating LED products that can output enough light to
> match filament lamps, but that's got little to do with the differences
in
> efficiency. It's because LED's are so efficient that creating the
> technology
> to make them comparable to filament lamps has actually happened.
**Only very high performance LEDs are significantly more efficient than
incadescents. Where they score very well, in in green and blue. Blue,
particularly, is a colour not easly produced by incandescents.
>
> Filament lamps have been around for longer than motor vehicles powered
by
> internal combustion engines have existed, but because they are so cheap
to
> make (which belies their inefficiency) they've persisted for almost 100
> years as the primary source of auxilliary lighting in motor vehicles.
**Of course. Simple and cheap. Just what the automotive industry lusts
after. Do not be misled, however. Your efficiency statements are way off
the
mark. And it's blindingly simple for you to prove it for yourself. Grab a
decent HALOGEN torch. Measure the current flow and the light output. Then
try to achieve the same figures with an LED. You'll need a Cree or Luxeon
emitter to do so. You'll find that, unless you are using the very latest
Cree devices, that the light delivered by the LED is similar to that
delivered by the halogen. The rest goes in heat. And for that, you need a
decent heat sink on the Cree or the Luxeon. They get hot. Bloody hot.
Trevor Wilson
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