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

On Mon, 14 Dec 2009 13:38:46 -0800 (PST), N8N
wrote:

34.99 (under 60 of your colonial dollars). I have one, it works
flawlessly and will comfortably power a B&M IQ Cyo which produces 60
Lux, which is five times the German legal required light output.
And that's how much with shipping?
34.99. *Free delivery.
To the YooEss? I kinda doubt it... Even Wiggle doesn't give free
shipping under about $80ish, and I can't see how they are making money
on orders at that level.

That's a UK site, I have no idea how much the same unit would cost
from a US shop but I can't recall ever having found any Japanese
manufactured item cheaper in the UK than in the US - usually it's very
much the other way around. Not to say it wouldn't happen, it would
just be unusual for it to be cheaper here than there.

Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt

On Mon, 14 Dec 2009 13:47:00 -0800, SMS
wrote:

$60 was just for a hub dynamo without the wheel? How much
is a whole wheel?

I don't know about you but I usually buy my bikes with a front wheel
(eccentric, I know). The Brompton was ordered with a SON on the
front, no charge was made for the build. My last wheel build cost me
£20, IIRC, but some people roll their own.

What you're missing here is that dynamo lighting is always on the
bike, a low theft risk in itself, and has a very long service life
often with close to zero maintenance.

Put it another way: how many cars require you to remember to recharge
the lights every night, or replace batteries every few weeks?

If you use a bike as a commuting vehicle then permanently fitted
always available lights make great sense, which is presumably why they
are so popular in Europe.

Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt

SMS wrote:
N8N wrote:

AFAICT, the best deal going in the US is the prebuilt VO front wheel
at about $120ish - I bought one. Unfortunately, the CR18 rear wheels
have been unavailable for months - I suspect that they may be
discontinuing them? - so the screaming dealness of the front wheel was
offset by the cost of having a rear wheel built at my LBS

LOL, so it's $60 was just for a hub dynamo without the wheel? How much
is a whole wheel? Peter White charges quite a bit for his custom wheels
with a dynohub, OTOH the VO wheel is a pretty good deal at $120,
"http://www.velo-orange.com/vopbprimwnoh.html." I'm going to pick one up
for my touring bike.

To be fair to Peter (and my LBS as well) the VO wheels use straight
gauge spokes, while I believe both Peter and my LBS use double-butted.
But if it's an issue, I'll address it when it occurs and not worry about
it in the meantime.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Just zis Guy, you know? wrote:
On Mon, 14 Dec 2009 13:38:46 -0800 (PST), N8N
wrote:

34.99 (under 60 of your colonial dollars). I have one, it works
flawlessly and will comfortably power a B&M IQ Cyo which produces 60
Lux, which is five times the German legal required light output.
And that's how much with shipping?
34.99. Free delivery.
To the YooEss? I kinda doubt it... Even Wiggle doesn't give free
shipping under about $80ish, and I can't see how they are making money
on orders at that level.

That's a UK site, I have no idea how much the same unit would cost
from a US shop but I can't recall ever having found any Japanese
manufactured item cheaper in the UK than in the US - usually it's very
much the other way around. Not to say it wouldn't happen, it would
just be unusual for it to be cheaper here than there.

Guy

I believe that that is in fact the case, likely because hub dynamos just
haven't got a whole lot of traction over here for some reason. Dunno
why; they're kinda cool. Guess they're not "racy" enough though.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On Dec 14, 3:37*pm, 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.

And it's a number that just doesn't matter!

Again: People have successfully commuted for decades using halogen
headlamps powered by generators. People have successfully competed in
all-day-all-night audax rides using the same equipment. Its silly to
pretend that sort of system is inadequate for those uses.

Generator powered LED lamps have now reached the level where they are
better than halogen. They put out even more light with even less
effort. That's the sort of efficiency that matters.

I recall the generator test article at
http://www.myra-simon.com/bike/dynotest.html
mentioning that the drag caused by really good generator sets is
equivalent to climbing ten feet per mile or less. That's a good
illustration of "negligible." And since the forward voltage of a
typical LED is less than that of a halogen bulb, I'd expect even less
drag if those same generators are powering an LED.

So what if the system includes a full wave rectifier that slightly
reduces that efficiency? Drag is still going to be less than with the
halogen - that is, less than negligible. Your theoretical drop in
efficiency just does not matter in any practical way.

- Frank Krygowski

"Frank Krygowski" wrote in message
...

I recall the generator test article at
http://www.myra-simon.com/bike/dynotest.html
mentioning that the drag caused by really good generator sets is
equivalent to climbing ten feet per mile or less. That's a good
illustration of "negligible." And since the forward voltage of a
typical LED is less than that of a halogen bulb, I'd expect even less
drag if those same generators are powering an LED.

It'll be higher with the good lights - they draw up to 4W via clever
electronics. (because you can do that sort of thing with LEDs). See past
posts by Andreas Oehler.

On Dec 14, 1:48*pm, "Just zis Guy, you know?"
wrote:
On Mon, 14 Dec 2009 13:38:46 -0800 (PST), N8N
wrote:

34.99 (under 60 of your colonial dollars). I have one, it works
flawlessly and will comfortably power a B&M IQ Cyo which produces 60
Lux, which is five times the German legal required light output.
And that's how much with shipping?
34.99. *Free delivery.
To the YooEss? *I kinda doubt it... *Even Wiggle doesn't give free
shipping under about $80ish, and I can't see how they are making money
on orders at that level.

That's a UK site, I have no idea how much the same unit would cost
from a US shop but I can't recall ever having found any Japanese
manufactured item cheaper in the UK than in the US - usually it's very
much the other way around. Not to say it wouldn't happen, it would
just be unusual for it to be cheaper here than there.

Earlier this year the USD/GBP exchange rate was quite favorable to get
myself a Shimano 3n72 dynohub from Wiggle instead of in the US.

-pm

In article ,
"Autymn D. C." writes:
On Dec 12, 3:43*am, "Androcles" wrote:
"Tom Keats" wrote in message
...
There seems to be a mindset that that is indeed what
bike riders need to do, either in terms of o/p wattage
or brightness. *In city traffic, blinking lights + speed
difference + positioning on the street does the trick
nicely -- as long as the batteries don't fade.
Post at nesci.physics instead then.

I'm posting at rec.bicycles.misc. If you don't like r.b.m
perhaps you should filter it in your newsreader.

The crossposting inflicted by the original post is neither
my fault nor my responsibility to rectify, so long as folks
from crossposted newsgroups (such as yourself) decide
to respond.

So get a lead-acid battery from a motor-cycle.
The weight won't affect your speed, just your acceleration,
and when you get tired pedalling you can run a motor from
it. Electrically propelled bicycles have been around for a while
now.
Anyway, bikes are faster than cars in city traffic which is why
couriers use them.
Weiht affects both, and bikes are freer than cars, not faster.

So you indeed /are/ interested in r.b.m topics.

And FYI, bikes often are faster than cars in city traffic.


--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca

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.

--
Dave Larrington
http://www.legslarry.beerdrinkers.co.uk
The System is well pleased with this Unit's performance, which
falls within expected parameters.

"Tom Keats" wrote in message
...
In article
,
"Autymn D. C." writes:
On Dec 12, 3:43 am, "Androcles" wrote:
"Tom Keats" wrote in message
...
There seems to be a mindset that that is indeed what
bike riders need to do, either in terms of o/p wattage
or brightness. In city traffic, blinking lights + speed
difference + positioning on the street does the trick
nicely -- as long as the batteries don't fade.
Post at nesci.physics instead then.

I'm posting at rec.bicycles.misc. If you don't like r.b.m
perhaps you should filter it in your newsreader.

The crossposting inflicted by the original post is neither
my fault nor my responsibility to rectify, so long as folks
from crossposted newsgroups (such as yourself) decide
to respond.

So get a lead-acid battery from a motor-cycle.
The weight won't affect your speed, just your acceleration,
and when you get tired pedalling you can run a motor from
it. Electrically propelled bicycles have been around for a while
now.
Anyway, bikes are faster than cars in city traffic which is why
couriers use them.
Weiht affects both, and bikes are freer than cars, not faster.

So you indeed /are/ interested in r.b.m topics.

And FYI, bikes often are faster than cars in city traffic.


I plonked that silly bitch years ago, it's still stupid enough
to respond to one of my posts.