"white" LED's vs. incandescent and halogen lights

On Mon, 14 Dec 2009 12:37:55 -0800, SMS wrote:

The loss of efficiency in rectification and regulation has been
explained here numerous times. I'm sure you can google it. Unlike
"darned bright" the loss of efficiency is an actual quantifiable number
based on the buck-boost regulator efficiency and the efficiency of a
full wave bridge rectifier.

Then don't use a full wave bridge rectifier (there's no need for it),
and don't use a buck-boost regulator (there's no need for it).

regards, Ian SMith
--
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Dave Larrington wrote:
In ,
SMS tweaked the Babbage-Engine to tell us:
Actually you could get
by with the 3W headlight, but that leaves nothing for the tail light
unless you get a 12V/6W tire driven dynamo, which costs $325.

Or you could do what sensible people do and use a battery-powered LED rear
light, which, unlike a front light, will run for the best part of a
Randonneur Round The Year season on a pair of AAAs.

No argument there, but someone in this thread was trying to find an LED
bulb for their rear dynamo powered light. The whole thing is ridiculous.
You want to not waste any of those 3 watts from the dynamo on a rear
"being seen" light. Especially because for a rear LED light you want one
with multiple LEDs, at least two of which are side pointing. Buy a
CatEye TD-LD1100 for $28 and be done with it.
"http://www.lickbike.com/productpage.aspx?PART_NUM_SUB=%273340-00%27"

On 15 Dec, 16:41, SMS wrote:
:
.. Especially because for a rear LED light you want one
with multiple LEDs, at least two of which are side pointing. Buy a
CatEye TD-LD1100 for $28 and be done with it.
"http://www.lickbike.com/productpage.aspx?PART_NUM_SUB=%273340-00%27"

Run it on 2900 mAh NiMHs and you are sorted.

--
Simon Mason

"SMS" wrote in message
...
Dave Larrington wrote:
In ,
SMS tweaked the Babbage-Engine to tell us:
Actually you could get
by with the 3W headlight, but that leaves nothing for the tail light
unless you get a 12V/6W tire driven dynamo, which costs $325.

Or you could do what sensible people do and use a battery-powered LED
rear light, which, unlike a front light, will run for the best part of a
Randonneur Round The Year season on a pair of AAAs.

No argument there, but someone in this thread was trying to find an LED
bulb for their rear dynamo powered light.

Um, no they weren't. They were looking for a replacement for the front.

I remember seeing LED replacement rear lamps about 15 years ago. Red was
always a lot easier than white.

The whole thing is ridiculous.

No, you are.

You want to not waste any of those 3 watts from the dynamo on a rear
"being seen" light.

Over 10 years ago I fitted my first LED lamp on my dynamo. 3W front, LED
rear. It works with more modern LED front lamps too - IQ Fly and IQ Cyo.
They've been used with both bottle and hub dynamos, and in both cases it
means the dynamo is putting out a bit more than 3W - there's no "waste" as
you describe it. (which reminds me, you still haven't come up with your
numbers yet). Rear lamps don't take much power at all.

Especially because for a rear LED light you want one with multiple LEDs,
at least two of which are side pointing.

Some manufacturers seem to make single LEDs work well. Lenses are wonderful
things.

On Dec 15, 8:41*am, SMS wrote:
No argument there, but someone in this thread was trying to find an LED
bulb for their rear dynamo powered light. The whole thing is ridiculous.
You want to not waste any of those 3 watts from the dynamo on a rear
"being seen" light.

An LED rear light draws what, 0.2 watts at most? (c'mon, you can work
it out from runtimes and the energy density of a battery)

-pm

MasonS wrote:

SMS wrote:

Especially because for a rear LED light you want one
with multiple LEDs, at least two of which are side pointing. Buy a
CatEye TD-LD1100 for $28 and be done with it.
"http://www.lickbike.com/productpage.aspx?PART_NUM_SUB=%273340-00%27"

Run it on 2900 mAh NiMHs and you are sorted.

Actually, a rear blinky is a great application for a low internal
discharge NiMH like the Rayovac Hybrid or Sanyo Eneloop. Even though
they hold 2000-2200mAh, which is less than a conventional NiMH, they
usually need less less frequent charging. They won't be ruined if you
forget about them for a year. A regular NiMH can easily lose more
juice to self-discharge than to running the blinky for a short time
each day.

Chalo

Chalo wrote:
MasonS wrote:
SMS wrote:
Especially because for a rear LED light you want one
with multiple LEDs, at least two of which are side pointing. Buy a
CatEye TD-LD1100 for $28 and be done with it.
"http://www.lickbike.com/productpage.aspx?PART_NUM_SUB=%273340-00%27"
Run it on 2900 mAh NiMHs and you are sorted.

Actually, a rear blinky is a great application for a low internal
discharge NiMH like the Rayovac Hybrid or Sanyo Eneloop. Even though
they hold 2000-2200mAh, which is less than a conventional NiMH, they
usually need less less frequent charging. They won't be ruined if you
forget about them for a year. A regular NiMH can easily lose more
juice to self-discharge than to running the blinky for a short time
each day.

This is true. But in reality, a rear LED light lasts so long on a set of
batteries that even alkalines are okay.

One thing to be sure of is to get a rear flasher that uses AA cells, not
AAA cells. The Blackburn Mars also has side pointing LEDs like the
CatEye TD-LD1100, but it uses AAA batteries.

On 15 Dec, 20:29, SMS wrote:
Chalo wrote:
MasonS wrote:
SMS wrote:
*Especially because for a rear LED light you want one
with multiple LEDs, at least two of which are side pointing. Buy a
CatEye TD-LD1100 for $28 and be done with it.
"http://www.lickbike.com/productpage.aspx?PART_NUM_SUB=%273340-00%27"
Run it on 2900 mAh NiMHs and you are sorted.

Actually, a rear blinky is a great application for a low internal
discharge NiMH like the Rayovac Hybrid or Sanyo Eneloop. *Even though
they hold 2000-2200mAh, which is less than a conventional NiMH, they
usually need less less frequent charging. *They won't be ruined if you
forget about them for a year. *A regular NiMH can easily lose more
juice to self-discharge than to running the blinky for a short time
each day.

This is true. But in reality, a rear LED light lasts so long on a set of
batteries that even alkalines are okay.

One thing to be sure of is to get a rear flasher that uses AA cells, not
AAA cells. The Blackburn Mars also has side pointing LEDs like the
CatEye TD-LD1100, but it uses AAA batteries.

So use lithiums.

On Dec 15, 11:41*am, SMS wrote:
Dave Larrington wrote:

Or you could do what sensible people do and use a battery-powered LED rear
light, which, unlike a front light, will run for the best part of a
Randonneur Round The Year season on a pair of AAAs.

No argument there, but someone in this thread was trying to find an LED
bulb for their rear dynamo powered light. The whole thing is ridiculous.

Nobody at all mentioned looking for a rear dynamo bulb!

You continue to astonish us.

- Frank Krygowski

Dave Larrington wrote:
Or you could do what sensible people do and use a battery-powered LED rear
light, which, unlike a front light, will run for the best part of a
Randonneur Round The Year season on a pair of AAAs.

SMS wrote:
No argument there, but someone in this thread was trying to find an LED
bulb for their rear dynamo powered light. The whole thing is ridiculous.

Frank Krygowski wrote:
Nobody at all mentioned looking for a rear dynamo bulb!
You continue to astonish us.

Of late, even dedicated dynamo aficionados run head only,
very few wired tail lamps now. Once seen as a 'freebie'
unit, LED blinkies (especially mounted high, on the rider)
have made tail lamps more 'free and worth every penny'.

Not advocating here, just reporting.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971