LED lighting...what's the best way?

[fungus]

On Sep 23, 4:59 pm, default wrote:

Leds don't usually die completely just get dimmer with time.

So they gradually reduce their own power to a
level their heatsink can cope with...?

That's very clever.

 

[Ecnerwal]

In article <r96p77plm64l9ov6qd8qpqh9uac30qps7e@4ax.com>, default wrote:

Leds don't usually die completely just get dimmer with time. That's
where some standardization in testing needs to be done. So they last
50,000 hours - but they are down to half the light output at 10,000
hours.

....the standard is actually 70% light output - so at 50,000 hours, it's
still on but at 70% of rated output. What you get from Chinese "brands"
that change every week so they are never around for warrantee problems
may differ. What you get if you overheat the die will also differ.

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

 

On Fri, 23 Sep 2011 08:07:53 -0700 (PDT), fungus
<openglMYSOCKS@artlum.com> wrote:

On Sep 23, 4:59 pm, default wrote:

Leds don't usually die completely just get dimmer with time.

So they gradually reduce their own power to a
level their heatsink can cope with...?

That's very clever.
No, not at all. They reduce the light output for the same power

dissipated. Specified in "Half-life." 50% luminous output at X
hours.

For instance my first night light used 3 red LEDs and was on
continuously for 5 years, at 2 years it was already down to half
brightness (subjectively) and probably half again in 4, and at 5 it
was only good for finding where the outlet was in the dark.

Some of the fancier "light engines" contain current regulators that
lower the output with high temps protecting the LEDs...

 

On Sat, 24 Sep 2011 09:50:45 -0400, Ecnerwal
<MyNameForward@ReplaceWithMyVices.Com.invalid> wrote:

Cats, coffee, chocolate...vices to live by

Vivaldi and home brew beer too.

 

[fungus]

On Sep 24, 7:57 pm, default wrote:

On Fri, 23 Sep 2011 08:07:53 -0700 (PDT), fungus

openglMYSO...@artlum.com> wrote:
On Sep 23, 4:59 pm, default wrote:

Leds don't usually die completely just get dimmer with time.

So they gradually reduce their own power to a
level their heatsink can cope with...?

That's very clever.

No, not at all.

Maybe I was too subtle...I meant the overheating
makes them dimmer so they're 'auto-adjusting'
themselves to the heatsink.

 

[fungus]

On Sep 24, 3:50 pm, Ecnerwal
<MyNameForw...@ReplaceWithMyVices.Com.invalid> wrote:

What you get from Chinese "brands" that change every week
so they are never around for warrantee problems may differ.
What you get if you overheat the die will also differ.

Some of the eBay sellers seem fairly serious.

The place I bought my small LEDs and controller
boards from provides proper datasheets, schematics,
etc. for everything (I'm guessing they manufacture
at least the controller boards themselves - the boards
are branded and nobody else on eBay has them).

Their warranty only covers DOA but I'm guessing
the LEDs you buy from 'reputable' places are
probably made in China too and will fail at about
the same rate. Buy some spares...

 

On Sat, 24 Sep 2011 11:59:04 -0700 (PDT), fungus
<openglMYSOCKS@artlum.com> wrote:

On Sep 24, 7:57 pm, default wrote:
On Fri, 23 Sep 2011 08:07:53 -0700 (PDT), fungus

openglMYSO...@artlum.com> wrote:
On Sep 23, 4:59 pm, default wrote:

Leds don't usually die completely just get dimmer with time.

So they gradually reduce their own power to a
level their heatsink can cope with...?

That's very clever.

No, not at all.

Maybe I was too subtle...I meant the overheating
makes them dimmer so they're 'auto-adjusting'
themselves to the heatsink.

Overheating permanently reduces the light output (forever no recovery)

Running them hot decreases efficiency reducing the light output but
only while hot (and there's a fine line between hot and overheated).