Dynamos vs. LEDs (Re: Cyclist Explodes! (NW Cambridge Plans))

Alan Braggins wrote on 09/10/2006 08:33 +0100:

Quoted message said:

In article said:

OTOH I have a pretty bright LED (as good as my 10W halogen) that gives
me a weeks commuting per recharge and comes with electronics to let me
know the batteries need recharging (but ensures I get home before the
light goes out).

Which one's that? I tried a Solidlights which was comparable to my
nominally 10W halogen at half charge (the halogen is unregulated),
but it wouldn't last a week's commute if I was doing the whole
16 miles each way at all. (It would probably last if I was doing my
usual trip just from the Park and Ride, but then it's all streetlit
and a Cateye EL300 is fine.

http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524442545731&FOLDER%3C%3Efolder_id=2534374302692895&bmUID=1160379849579
It has two settings so most of the time I use it on the low power
setting, switching to high power for the unlit roads. All for about £35.

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci

Tony Raven said:

http://www.mec.ca/

I do wish MEC had a branch in the UK, preferably Scotland, preferably
Dundee... We're members, but it's a bit of a trek to the nearest one
and they won't post canoe paddles :-(

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch wrote on 09/10/2006 09:27 +0100:

Quoted message said:

Tony Raven said:

http://www.mec.ca/

I do wish MEC had a branch in the UK, preferably Scotland, preferably
Dundee... We're members, but it's a bit of a trek to the nearest one
and they won't post canoe paddles :-(

Good thing too - our stock up trips there are invariably very expensive
affairs - there is so many "ooh, look at this" moments going round the
store and you've just got to get it while you are there.

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci

In article <[email hidden]>,

Alan Braggins said:

while, but it's a bit feeble compared with a modern dynamo and I didn't
have the optimal bulb and even when it was turned off the gears felt
draggier than the other hub. The bike I do the longer journey on has

Some vague bit of the back of my brain is telling me that some old
dynamo hubs actually provide more resistance to motion when there
isn't any current being drawn...

--
Jonathan Amery. Let faith be my shield and let joy be my steed
##### 'Gainst the dragons of anger, the ogres of greed;
#######__o And let me set free, with the sword of my youth,
#######'/ From the castle of darkness the power of truth." - Struther

Jonathan Amery said:

Some vague bit of the back of my brain is telling me that some old
dynamo hubs actually provide more resistance to motion when there
isn't any current being drawn...

That was the case for the very first model of the Shimano dynohub.
They fixed it in later versions.

--
Arthur Clune

In article said:

In article <[email hidden]>,

Alan Braggins said:

while, but it's a bit feeble compared with a modern dynamo and I didn't
have the optimal bulb and even when it was turned off the gears felt
draggier than the other hub. The bike I do the longer journey on has

Some vague bit of the back of my brain is telling me that some old
dynamo hubs actually provide more resistance to motion when there
isn't any current being drawn...

True of the early Shimano ones at high speed:
http://www.myra-simon.com/bike/dynotest.html

But in the case of the SA three speeds I was using, it was also noisier,
so I think it was mechanical. Or maybe I just imagined the drag because
of the noise. They did both came off scrap bikes.

LEDs aren't very good at generating electricity; if your dynamo is
generating much visible light, you are well advised not to approach
the bicycle.

Does any more need to be said about comparing these?

More seriously, the thing that pisses me off about LED lights is
the way that they are all designed to use the nasty little AA (and,
worse, AAA or coin-shaped) batteries. Ones designed to use D (or
even C) cells (or to operate from dynamos) and to generate a wide,
bright light seem to be almost unobtainable.

Regards,
Nick Maclaren.

Nick Maclaren said:

More seriously, the thing that pisses me off about LED lights is
the way that they are all designed to use the nasty little AA (and,
worse, AAA or coin-shaped) batteries.

Most, yes, but not all.

Quoted message said:

Ones designed to use D (or
even C) cells (or to operate from dynamos) and to generate a wide,
bright light seem to be almost unobtainable.

My Streetmachine runs LED lamps front and rear from a dynohub: the
DLumotec Oval Senso Plus and DToplight Plus pair running from a SON.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Nick Maclaren said:

More seriously, the thing that pisses me off about LED lights is
the way that they are all designed to use the nasty little AA (and,
worse, AAA or coin-shaped) batteries. Ones designed to use D (or
even C) cells (or to operate from dynamos) and to generate a wide,
bright light seem to be almost unobtainable.

They seem to coming in now - I have a BuM Topal, which is pretty good,
and recently got a Basta one, which although a good bit cheaper, seems
as bright as the BuM. Both have stand-lights, and project enough light
to see by in the woods, although at reduced speeds.

sothach said:

Nick Maclaren said:

More seriously, the thing that pisses me off about LED lights is
the way that they are all designed to use the nasty little AA (and,
worse, AAA or coin-shaped) batteries. Ones designed to use D (or
even C) cells (or to operate from dynamos) and to generate a wide,
bright light seem to be almost unobtainable.

They seem to coming in now - I have a BuM Topal, which is pretty good,
and recently got a Basta one, which although a good bit cheaper, seems
as bright as the BuM. Both have stand-lights, and project enough
light to see by in the woods, although at reduced speeds.

<AOL>

Plus there's the Solidlights 1203D, which sadly is not available in a
Lightspin-compatible version :-(

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
It is not possible to call a complex number from a phone box.

(Nick Maclaren) said:

LEDs aren't very good at generating electricity; if your dynamo is
generating much visible light, you are well advised not to approach
the bicycle.

Does any more need to be said about comparing these?

More seriously, the thing that pisses me off about LED lights is
the way that they are all designed to use the nasty little AA (and,
worse, AAA or coin-shaped) batteries. Ones designed to use D (or
even C) cells (or to operate from dynamos) and to generate a wide,
bright light seem to be almost unobtainable.

B&M do the DLumotec Oval, an LED version of their "Oval" front light.

Solidlights 1203D is also a dynamo driven LED light.

Tim

In article <[email hidden]>,
Tim Hall <[email hidden]> writes:
|>
|> B&M do the DLumotec Oval, an LED version of their "Oval" front light.
|>
|> Solidlights 1203D is also a dynamo driven LED light.

Thanks everyone. At long last, things are looking up in that area!
I am still complete baffled why it didn't happen before, given that
white or whitish and red LEDs have been cheap for a long time now.

Regards,
Nick Maclaren.

Nick Maclaren said:

I am still complete baffled why it didn't happen before, given that
white or whitish and red LEDs have been cheap for a long time now.

Partly because they only changed the British Standard to make them
legal last year. But I'm amazed, I had no idea they were so good.
Still, I'm happy with my CatEyes and rechargeables (almost all on lit
streets, though)
cheers, Tim.

Nick Maclaren said:

In article <[email hidden]>,
Tim Hall <[email hidden]> writes:
|>
|> B&M do the DLumotec Oval, an LED version of their "Oval" front light.
|>
|> Solidlights 1203D is also a dynamo driven LED light.

Thanks everyone. At long last, things are looking up in that area!
I am still complete baffled why it didn't happen before, given that
white or whitish and red LEDs have been cheap for a long time now.

And it comes full circle as the company that produces Solidlights is
based in Cambridge.

Might be worth giving them a call and seeing if you can drop in to get
a demo.

-Alex

Tim B said:

Partly because they only changed the British Standard to make them
legal last year. But I'm amazed, I had no idea they were so good.
Still, I'm happy with my CatEyes and rechargeables (almost all on lit
streets, though)
cheers, Tim.

What I really meant was that I had no idea hub dynamos were so good!
sorry.

Tim B said:

What I really meant was that I had no idea hub dynamos were so good!
sorry.

A few years ago I was very much of the opinion that no bike of mine
would ever have (a) a bell, (b) a stand or (c) a dynamo. (a) and (b)
because I regarded them as pointless and (c) because they all seemed to
be [censored] in the face of good rechargeables.

When I got my recumbent tourer I asked existing owners what the No
Brainer factory options were, and the dynohub lighting was a common
answer. I decided they couldn't /all/ be wrong and it turned out they
weren't. Was impressed enough to get another SON for the Brompton, and
subsequently Roos bought a similar 'bent tourer with a SON, and Santa
brought her a Shimano dynohub for her hack bike.

The SON hubs are the badgers' nadgers, the Shimano ones aren't quite as
nice but not that far off, and are quite a bit cheaper. For routine
trouble free road use where serious weight-weenieage isn't in order
they're very hard to beat IMHO, especially if (like me) you're not very
good with the discipline of keeping cells charged properly.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

In article said:

More seriously, the thing that pisses me off about LED lights is
the way that they are all designed to use the nasty little AA (and,
worse, AAA or coin-shaped) batteries. Ones designed to use D (or
even C) cells (or to operate from dynamos) and to generate a wide,
bright light seem to be almost unobtainable.

Modern cheap AA NiCds have the same capacity that typical Ds did some
years back (and many modern C and D cells are the same capacity just
in a larger package, though you can get more expensive higher capacity
ones).

A Cateye EL300 will last for over 8 hours on a set of AA NiCds. LEDs that
are actually capable of using the higher capacity of larger cells (at
least on a commute, not 24 hour endurance races) are relatively rare and
expensive.

In article <[email hidden]>,
[email hidden] (Alan Braggins) writes:
|>
|> Modern cheap AA NiCds have the same capacity that typical Ds did some
|> years back (and many modern C and D cells are the same capacity just
|> in a larger package, though you can get more expensive higher capacity
|> ones).

Yeah, but that's NiCads. The same is NOT true for simple alkaline
primary batteries, which are still the most common ones. D cells
have getting on for 10 times the capacity of AA cells and nowhere near
the same cost factor. Note that using current more slowly is generally
more efficient.

|> A Cateye EL300 will last for over 8 hours on a set of AA NiCds. LEDs that
|> are actually capable of using the higher capacity of larger cells (at
|> least on a commute, not 24 hour endurance races) are relatively rare and
|> expensive.

Eh? An LED doesn't burn out THAT fast!

You almost certainly mean that individual LEDs can't use much current,
but why the hell not use more than one LED? Most cyclists' lights
(and even front lights for 90% of commuting) are primarily to be seen,
and not to see by and you need the width anyway (as I said).

Having to change or recharge the batteries once every few weeks is a
pain in the neck, at best.

Regards,
Nick Maclaren.

In article said:

[email hidden] (Alan Braggins) writes:
|>
|> Modern cheap AA NiCds have the same capacity that typical Ds did some
|> years back (and many modern C and D cells are the same capacity just
|> in a larger package, though you can get more expensive higher capacity
|> ones).

Yeah, but that's NiCads. The same is NOT true for simple alkaline
primary batteries, which are still the most common ones.

For regular commuting? I very much doubt it. (Actually NiMH has probably
largely taken over now, but the generalisation above remains true of NiMH.)

Quoted message said:

|> A Cateye EL300 will last for over 8 hours on a set of AA NiCds. LEDs that
|> are actually capable of using the higher capacity of larger cells (at
|> least on a commute, not 24 hour endurance races) are relatively rare and
|> expensive.

Eh? An LED doesn't burn out THAT fast!

I'm not sure what your point is here. The batteries running out of charge
has nothing to do with LEDs burning out (though an LED will burn out THAT
fast if you put a few amps though it, and AAs are fine for lower currents).

Quoted message said:

You almost certainly mean that individual LEDs can't use much current,
but why the hell not use more than one LED?

The EL300 uses five, as it happens, but the newer EL530 uses a single
higher power one for similar or greater brightness.

There are flashlights using multiple 3W or 5W Luxeons that run off D cells
(or, in some cases, D cell sized adaptors taking three AA cells in parallel
giving a higher capacity/cost), but, as I said, they are relatively rare and
expensive.

Quoted message said:

Most cyclists' lights
(and even front lights for 90% of commuting) are primarily to be seen,
and not to see by and you need the width anyway (as I said).

Which is why most cyclists are quite happy with the lower powered
lights for which the AA cells are adequate anyway.

Quoted message said:

Having to change or recharge the batteries once every few weeks is a
pain in the neck, at best.

Use a dynamo then. I doubt much of a market exists for lights which are
bulkier and heavier but only need recharging less frequently.