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

[Jonathan Amery]

In article <[email protected]>,
Nick Maclaren <[email protected]> wrote:
>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).

My lights are definitely to see by, with unlit roads and the
riverside route being common places where I cycle.

My spare "see me" only light hasn't had any changes of batteries in
about 5 years.

--
Jonathan Amery. "Just imagine what would happen if there
##### was a world shortage of semicolons."
#######__o
#######'/ - Jamie Cruise on C Programming.

 

[Nick Maclaren]

In article <[email protected]>,
[email protected] (Alan Braggins) writes:
|> >
|> >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.)

Well, you could be right, but I doubt it. At least NiMH isn't the
pollution nightmare of NiCad.

|> >|> 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).

The point is that you don't have to change or recharge them with such
maddening frequency. It is that sort of little nuisance that puts a
lot of people off cycling, as much as the major issues.

|> > 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.

They may be; they are insane to be. Most of those can't be seen except
from almost dead ahead or dead behind, which is why they were banned
for so long. To be seen, you need to be seen from a fair angle, or
drivers turning out of side roads won't see you.


Regards,
Nick Maclaren.

 

[Douglas de Lacey]

Nick Maclaren wrote:
> In article <[email protected]>,
> [email protected] (Alan Braggins) writes:
> |> >
> |> >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.)
>
> Well, you could be right, but I doubt it. At least NiMH isn't the
> pollution nightmare of NiCad.
>
> |> >|> 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).
>
> The point is that you don't have to change or recharge them with such
> maddening frequency. It is that sort of little nuisance that puts a
> lot of people off cycling, as much as the major issues.
>
> |> > 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.
>
> They may be; they are insane to be. Most of those can't be seen except
> from almost dead ahead or dead behind, which is why they were banned
> for so long. To be seen, you need to be seen from a fair angle, or
> drivers turning out of side roads won't see you.

But what's the problem with lights that use small batteries, Nick? My
third set of lights is two pound-coin sized single-LED lamps, and while
the front won't illuminate a dark street they are both very bright and
pertty omni-directional (my major complaint about the front one is that
it's too bright for my own eyes). A fiver for the pair: I shan't exactly
weep if I have to throw them away when eventually the batteries go.

Douglas de Lacey

 

[Nick Maclaren]

In article <[email protected]>,
Douglas de Lacey <[email protected]> writes:
|>
|> But what's the problem with lights that use small batteries, Nick? My
|> third set of lights is two pound-coin sized single-LED lamps, and while
|> the front won't illuminate a dark street they are both very bright and
|> pertty omni-directional (my major complaint about the front one is that
|> it's too bright for my own eyes). A fiver for the pair: I shan't exactly
|> weep if I have to throw them away when eventually the batteries go.

Er, I think that you have just broken a few rules of physics ....

Pinpoint brightness may glare close to, but does not 'carry' unless
it is very tightly beamed. Basic physics says that you need battery
capacities proportional to the brightness times the beam area times the
life of the battery, and most LEDs are only half a dozen times more
efficient than a decent (bicycle-sized) incandescent bulb. And a D cell
has getting on for 10 times the capacity of an AA cell.

What I want is something that will give a BETTER light than an average
incandescent and last LONGER than one - e.g. for a complete winter of
commuting. There is no reason that such things couldn't be made.


Regards,
Nick Maclaren.

 

[Anthony Jones]

Nick Maclaren wrote:
> most LEDs are only half a dozen times more
> efficient than a decent (bicycle-sized) incandescent bulb.

Comparing widely available LEDs to a halogen bulb as used in a good dynamo
headlight would give you a factor of less than two.

> And a D cell
> has getting on for 10 times the capacity of an AA cell.

Not for NiMH last time I looked. Personally I would rather not be filling
landfill with dead alkaline batteries.

> What I want is something that will give a BETTER light than an average
> incandescent and last LONGER than one - e.g. for a complete winter of
> commuting. There is no reason that such things couldn't be made.

It would weigh a ton. The D size batteries are heavy by themselves, and then
you'd need casing strong enough to support them in an environment with
plenty of vibration. Why not just get a dynamo?

Anthony

 

[Anthony Jones]

Nick Maclaren wrote:
> They may be; they are insane to be. Most of those can't be seen except
> from almost dead ahead or dead behind, which is why they were banned
> for so long.

Do you have any evidence whatsoever to support the assertion that this is
why they were banned?

Anthony

 

[Anthony Jones]

Nick Maclaren wrote:
> 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.

High power (>100mW) LEDs are a fairly recent development. Using a large
cluster of low power LEDs introduces numerous difficulties.

Anthony

 

[Pyromancer]

Upon the miasma of midnight, a darkling spirit identified as Peter
Clinch <[email protected]> gently breathed:

>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.

My Gazelle has a Shimano Nexus dynohub in the front wheel, driving the
front light only, the rear is a battery-powered LED.

The bulb in the front lamp is actually a little thing which looks like a
fairy light, but boy is it bright! Some kind of halogen, from he purity
and intensity of the light it chucks out.

I've no idea what kind of battery the rear takes, I've not had to
replace it yet, I'm assuming a pair of AAs judging by the size of the
housing, but they're lasting fine so far, and as I often work late I've
been frequently riding in the dark since August.

The thought of adding extra LED lamps does appeal, I'm wondering what
else the dynamo could drive - presumably it'd have to be instead of the
existing front light, but would I get even brighter light from LED
fronts, possibly a pair mounted under the bars either side of the
headset?

Though TBH I'll probably get a computer first, would like to know what
speed and cadence I'm doing.

I've sometimes wondered if anyone's done "full electrics" on a bike -
dynamo charging a bigish battery, which in turn powers front lights,
rear lights - poss even flashing yellow LED indicators?

--
- DJ Pyromancer, The Sunday Goth Social, Leeds. <http://www.sheepish.net>

Broadband, Dialup, Domains = <http://www.wytches.net> = The UK's Pagan ISP!
<http://www.inkubus-sukkubus.co.uk> <http://www.revival.stormshadow.com>

 

[Clive George]

"Nick Maclaren" <[email protected]> wrote in message
news:[email protected]...

> What I want is something that will give a BETTER light than an average
> incandescent and last LONGER than one - e.g. for a complete winter of
> commuting. There is no reason that such things couldn't be made.

Obviously such things could be made - eg you could do so yourself.

There is a good reason why such things are not available commercially :
there's no market. Dynamo, esp hub, covers the 'lasting for ever' market.
People aren't prepared to carry a big heavy battery - ie one which will last
for a complete winter - for something which only puts out a modest amount of
light. And TBH alkalines are **** anyway - leave the light on for a
day/night, and there goes an awful lot of commuting light.

I'd suggest a SON + suitable LED front/back lamps does exactly what you want
: "BETTER" than average incandescant, and obviously lasts LONGER than one
since you're supplying the power. No batteries to go flat, only downside is
cost.

cheers,
clive

 

[Alan Braggins]

In article <[email protected]>, Nick Maclaren wrote:
>[email protected] (Alan Braggins) writes:
>
>|> >|> 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).
>
>The point is that you don't have to change or recharge them with such
>maddening frequency.

I still don't see what the lifetime of an LED (thousands of hours) has to
do with it. It's an advantage over bulbs, certainly, but that didn't seem
to be your point.
If you actually meant "an LED light doesn't drain its batteries in only
8 hours", no it doesn't. I once left it on for 8 hours, and it was still
at full brightness as far as I could see. Cateye claim 20 hours at full
brightness on alkalines, but I don't believe anyone would use non-rechargable
batteries to merely double the life for regular commuting.
Since LEDs (unlike bulbs) get more efficient at lower currents, it's usable
as a just being seen by light for much longer than that.

 

[Tim Forcer]

On 9 Oct 2006 17:14 Nick Maclaren wrote:

[cut]

> |> > 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.
>
> They may be; they are insane to be. Most of those can't be seen except
> from almost dead ahead or dead behind, which is why they were banned
> for so long. To be seen, you need to be seen from a fair angle, or
> drivers turning out of side roads won't see you.

While the more expensive filament bike lights certainly had
substantially wider beam patterns than LED, that wasn't true of the
"general consumption" units sold under Ever Ready and Halfords brands.
Of course, the cheapo LED lights were unsophisticated too, more like
Christmas decorations in many cases. Since I only do night riding in
town, I merely followed developments in lighting with academic
interest (apart from fitting the brightest bulb I could in my twin-D
cell lights).

In recent years, incandescent lights seem to have been getting
smaller, while LED lights have been getting bigger. The sharper beam
cut-off of the latter is still an issue, sure, but "why they were
banned"?

I do wonder if at least part of the reason for lifting the ban on LED
lights was the introduction of LEDs to car light clusters and traffic
lights - difficult to victimise cyclists. Ah. I see the flaw in that
argument. Sorry.

--
Tim Forcer [email protected]
The University of Southampton, UK

The University is not responsible for my opinions

 

[Peter Clinch]

Nick Maclaren wrote:

> 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).

The latest generation of higher power LEDs allow you to use a single
unit for the same light, though the optical side of things with lenses
and reflectors is much easier with a single LED than a cluster.

It's not just bike lights that are going this way, but premium
headtorches too: single high power LEDs are replacing clusters, and
they're /better/.

I put my new single LED DLumotec Oval to its first test last night: most
impressive, considerably better than the halogen bulbed unit it
replaced, and I used to think that was pretty good.

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

Yup. That's why I use dynamos now.

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 protected] http://www.dundee.ac.uk/~pjclinch/

 

[Alan Braggins]

In article <[email protected]>, Nick Maclaren wrote:
>|> Which is why most cyclists are quite happy with the lower powered
>|> lights for which the AA cells are adequate anyway.
>
>They may be; they are insane to be. Most of those can't be seen except
>from almost dead ahead or dead behind, which is why they were banned
>for so long.

The EL300 has a British Standard approval and was never banned.
(And if you were a real pedant, you would realise that non-approved
white lights weren't banned anyway, they merely weren't acceptable as
the only front lights.)

If you are talking about the old poxy feeble green things, they ran
quite happily for weeks on AAAs. I meant lower powered compared to
something like a 10W halogen, or the Solidlights 1303 (3x2W LEDs),
for which 4 AAs are not adequate.

And I still really have difficulty believing you are serious about
having to recharge batteries once a week or twice a month being
seriously offputting, and that having a bike light too heavy and
bulky to take off a bike and walk around with is a sensible answer
to that.

 

[Dave Larrington]

Peter Clinch wrote:

> I put my new single LED DLumotec Oval to its first test last night:
> most impressive, considerably better than the halogen bulbed unit it
> replaced, and I used to think that was pretty good.

<AOL>

Though I am hanging onto my E6 until such time as ACP tell us what the
lighting regs are going to be on The French Ride...

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
And then there was light and He thought it was good, so He threw
the receipt away.

 

[Mike Clark]

In message <[email protected]>
[email protected] (Nick Maclaren) wrote:

[snip]
>
> The point is that you don't have to change or recharge them with such
> maddening frequency. It is that sort of little nuisance that puts a
> lot of people off cycling, as much as the major issues.
>

I now use a Cateye EL500 which takes 4 x AA NiMh cells as my main front
light and a Cateye AU100 which takes 2 x AA NiMh cells as my rear light.
I recharge them every 2-3 weeks and before they have run down. I also
carry a spare set of lights in my rucksack with AA alkaline cells as an
emergency backup (I rarely need to get them out).

LED lighting has come on a long way and the cells last a long time
between charges. I doubt whether there would be significant advantage
from having fewer D cells in place of the NiMh AA cells.

LED lighting is also widely used for mountaineering and caving. My
caving lamp is a multi-LED lamp from Speleotechnics
( http://www.speleo.co.uk/ ) which uses a water-proof sealed case
containing NiMh cells and although it has a halogen mainbeam I rarely
need to use that since the LED light is so bright and throws an even
light over a large angle. These lamps last for a whole weekends caving
underground on one charge (12-16 hours) with plenty of spare capacity.


> |>
> |> Which is why most cyclists are quite happy with the lower powered
> |> lights for which the AA cells are adequate anyway.
>
> They may be; they are insane to be. Most of those can't be seen except
> from almost dead ahead or dead behind, which is why they were banned
> for so long. To be seen, you need to be seen from a fair angle, or
> drivers turning out of side roads won't see you.
>

The AA NiMh powered Cateye lamps that I have on my bicycle are bright
enough to be seen from a long distance, have LEDs or prisms that direct
light to the sides allowing visibility from all directions, and the
front lamp is bright enough to see by on unlit tracks and roads. Also
they do not need recharging with anything like the frequency I used to
have to change or recharge D cells in my old incandescent Cateye.

I think the LED lamps that you are referring to Nick are some of the
older designs that also probably aren't approved by the standards.

Mike
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | immunology lecturer, antibody engineer and
` || (_)/ (_) | \corn computer user"

 

[Nick Maclaren]

In article <[email protected]>,
[email protected] (Alan Braggins) writes:
|>
|> The EL300 has a British Standard approval and was never banned.

Sigh. I took the trouble to actually check the relevant law and
regulations, following such an exchange and an unbelievable (but
true) statement by someone.

Until the (relatively) recent change, the only bicycle lights approved
were Raleigh's voltage (sic) incandescent; it wasn't clear whether
even halogen bulbs were permitted. The Construction and Use Regulations
made it a crime only to sell bicycles with non-approved lights; the
Highway Code merely made it evidence of your negligence to use them
if some else claimed they couldn't see you.

|> (And if you were a real pedant, you would realise that non-approved
|> white lights weren't banned anyway, they merely weren't acceptable as
|> the only front lights.)

That is false, and I believe that it still is. The Construction and
Use Regulations applied (and may still apply) to any lights fitted to
the vehicle; to evade them, you have to wear the lights (which is why
there was and still is a practice of doing so.)

|> And I still really have difficulty believing you are serious about
|> having to recharge batteries once a week or twice a month being
|> seriously offputting, and that having a bike light too heavy and
|> bulky to take off a bike and walk around with is a sensible answer
|> to that.

My beliefs are the unimportant aspect; it is those of the average Joe
in his motor car that matter.

You really should try speaking to a few more people who have tried
cycle commuting and given it up, who are reluctant to try it and so
on. One of the main reasons that cycling is not going to make any
headway among the general population is the unreasonable claims of
the fanatics. A hell of a lot of people say:

Oh, the cyclists say X, but that is nonsense, so it isn't possible
for me to commute by bicycle.

The premise is often true; the deduction rarely is.


Regards,
Nick Maclaren.

 

[Alistair Gunn]

In uk.rec.cycling Pyromancer twisted the electrons to say:
> The thought of adding extra LED lamps does appeal, I'm wondering what
> else the dynamo could drive - presumably it'd have to be instead of the
> existing front light, but would I get even brighter light from LED
> fronts, possibly a pair mounted under the bars either side of the
> headset?

Well the dynamo should be capable of driving something like a DToplight
Plus at the back as well as your current front light (though you might
need to change the bulb?). As for the front, well you could always fit a
Solidlight 1203D? ... and if you can come up with a good financial
excuse for that, please let me know so I can use it on myself! <grins>

> I've sometimes wondered if anyone's done "full electrics" on a bike -
> dynamo charging a bigish battery, which in turn powers front lights,
> rear lights - poss even flashing yellow LED indicators?

Shimano (IIRC?) have a system where the hub dynamo is also used to drive
the cycle computer, which in turn is used to work out when you are
accelerating from stationary (in which case it hardens/locks the
suspension forks). Not quite what you're talking about, but related
enough I felt it worth bring up ...
--
These opinions might not even be mine ...
Let alone connected with my employer ...

 

[Clive George]

"Nick Maclaren" <[email protected]> wrote in message
news:[email protected]...

> My beliefs are the unimportant aspect; it is those of the average Joe
> in his motor car that matter.
>
> You really should try speaking to a few more people who have tried
> cycle commuting and given it up, who are reluctant to try it and so
> on. One of the main reasons that cycling is not going to make any
> headway among the general population is the unreasonable claims of
> the fanatics. A hell of a lot of people say:
>
> Oh, the cyclists say X, but that is nonsense, so it isn't possible
> for me to commute by bicycle.
>
> The premise is often true; the deduction rarely is.

Can you give an example of this wrt bike lighting?

I can't think of one - the general case appears to be that nobody cares
about the specific laws, and that if they want lights they'll fit what they
can get.

cheers,
clive

 

[Simon Brooke]

in message <[email protected]>, Nick Maclaren
('[email protected]') wrote:

> 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).

You're an urban cyclist, aren't you? Some of us aren't. You may be right
that 90% of commuters ride only on lighted streets, but I wouldn't bet on
it.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; Life would be much easier if I had the source code.

 

[Rob Morley]

In article <[email protected]>
Nick Maclaren <[email protected]> wrote:
<snip>
>
> They may be; they are insane to be. Most of those can't be seen except
> from almost dead ahead or dead behind, which is why they were banned
> for so long.

They were never 'banned', they simply didn't comply with the relevant
standard which stated that an incandescent light source was required.