Help Me Choose A Headlight

  • Thread starter Prisoner at War
  • Start date



Bill wrote:
> SMS wrote:
>> Bill wrote:
>>
>>> The Tungsten is more prone to breaking from the vibration in a bike
>>> than in a car, and that is more than in a house light. Filaments burn
>>> out in a supernova, LEDs may dim over years, and HIDs may dim just a
>>> bit after a bunch of years.
>>> Three different types of light.
>>
>> Personally, I'd rather over-voltage a quartz-halogen lamp to achieve
>> the illumination level of HID, and carry a spare bulb for when it
>> burns out in that supernova.
>
> That works only if you have a sanitary, well clean, cloth to change the
> bulb. The Quartz will shatter from the skin oils if you touch it.

Not if you're using MR11 or MR16 lamps, which most rechargeable bicycle
lights now use. You don't touch the actual bulb, just the reflector/lens.
 
SMS wrote:
> Bill wrote:
>> SMS wrote:
>>> Bill wrote:
>>>
>>>> The Tungsten is more prone to breaking from the vibration in a bike
>>>> than in a car, and that is more than in a house light. Filaments
>>>> burn out in a supernova, LEDs may dim over years, and HIDs may dim
>>>> just a bit after a bunch of years.
>>>> Three different types of light.
>>>
>>> Personally, I'd rather over-voltage a quartz-halogen lamp to achieve
>>> the illumination level of HID, and carry a spare bulb for when it
>>> burns out in that supernova.
>>
>> That works only if you have a sanitary, well clean, cloth to change
>> the bulb. The Quartz will shatter from the skin oils if you touch it.
>
> Not if you're using MR11 or MR16 lamps, which most rechargeable bicycle
> lights now use. You don't touch the actual bulb, just the reflector/lens.

Yeah,
Situations vary. Many car bulbs have no protection and I have zero
experience with bike bulbs. I like LEDs.
Bill Baka
 
Prisoner at War wrote:
> I'm wondering whether to get the Light & Motion ARC Li-Ion Ultra HID
> or the NiteRider Moab HID/LED. They're both the same price but the
> NiteRider burns over 50% longer at the same highest level of
> brightness (if I'm reading the specs right -- in which case I'm
> surprised Light & Motion haven't lowered their price at all; also, I'm
> not sure what it means for the NiteRider to be "HID/LED" [according to
> performancebike.com, anyway])....

I've updated the HID/LED section of the Bicycle Lighting website
"http://bicyclelighting.com". Note that this site was primarily a site
for building homebrew lighting systems, not a site to evaluate every
commercial lighting system on the market. As such, I've now included the
TrailTech lamps because they are usable in a homebrew system, but not
included the insanely over-priced commercial HID systems.

I've also added the few good Luxeon LED lamps, since several readers
requested this information, though the good LED lamps are nearly as
expensive as the TrailTech HID lamps.

The direct link to the HID/LED section is
"http://nordicgroup.us/s78/hidled.html"

Again, this site is primarily to help people construct their own
high-performance lighting systems. It's been expanded over the years to
include information on other options, including a section that explains
the pros and cons of dynamo systems at
"http://nordicgroup.us/s78/dynamo.html".
 
Bill wrote:

> Yeah,
> Situations vary. Many car bulbs have no protection and I have zero
> experience with bike bulbs. I like LEDs.

Once you get into the higher power LEDs you have heat issues as well.
For example, the inolights had a problem where components were
desoldering themselves due to excessive heat. The 5W Luxeon lamps don't
have the same essentially unlimited lifetime that the low power LEDs have.

For lights with high brightness and high efficiency, I think we'll all
eventually be using HID lamps eventually, the LED lamps have too many
issues with beam coherency and heat diffusion. They're great for "being
seen" lamps, and for low wattage flashlights, but not for things like
headlights.
 
SMS wrote:
> Bill wrote:
>
>> Yeah,
>> Situations vary. Many car bulbs have no protection and I have zero
>> experience with bike bulbs. I like LEDs.
>
> Once you get into the higher power LEDs you have heat issues as well.
> For example, the inolights had a problem where components were
> desoldering themselves due to excessive heat. The 5W Luxeon lamps don't
> have the same essentially unlimited lifetime that the low power LEDs have.

I have had the problem of diodes coming unsoldered in power supplies
that I was 'supposed to be' the head engineer on, but the boss decided
they were 'good enough' to ship. Needless to say I was indignant about
shipping a product with a known failure mode, but over-ruled by
management. The same probably happened in the design of the self
unsoldering inolights.
>
> For lights with high brightness and high efficiency, I think we'll all
> eventually be using HID lamps eventually, the LED lamps have too many
> issues with beam coherency and heat diffusion. They're great for "being
> seen" lamps, and for low wattage flashlights, but not for things like
> headlights.
>
Give it time. HID lamps require a lot of drive electronics no matter
what type they are, and LED lamps can be limited with a simple resistor,
as is my Cateye with 5 LEDs. An active switching power supply could
ensure better efficiency but would drive the cost of a $30 light to
about $50, $15 of that being profit. I think LEDs will get bigger and
better over time until they can take over the HID type. Computers double
in power about every 2 years and some of that research applies to LEDs
as a side effect in materials research. Consider that I have seen LASER
LEDs in big metal power packages so visible LEDs could go there if there
were more demand than just the bicycle market.
Bill Baka
 
On May 3, 8:58 pm, SMS <[email protected]> wrote:
> Bill wrote:
> > SMS wrote:
>
> >> Personally, I'd rather over-voltage a quartz-halogen lamp to achieve
> >> the illumination level of HID, and carry a spare bulb for when it
> >> burns out in that supernova.
>
> > That works only if you have a sanitary, well clean, cloth to change the
> > bulb. The Quartz will shatter from the skin oils if you touch it.
>
> Not if you're using MR11 or MR16 lamps, which most rechargeable bicycle
> lights now use. You don't touch the actual bulb, just the reflector/lens.

And to get back to optics, it's the MR11 and MR16 bike lights that
have no road-specific optics. These are the ones that require 10 to
20 watts or more to give adequate road illumination, necessitating a
bigger battery and/or a shorter run time, while blinding oncoming road
users and washing out the rider's night vision.

Lamps designed for illuminating wall hangings just aren't optimum for
bike lights.

- Frank Krygowski
 
On May 3, 9:27 pm, SMS <[email protected]> wrote:
>
>
> Again, this site is primarily to help people construct their own
> high-performance lighting systems. It's been expanded over the years to
> include information on other options, including a section that explains
> the pros and cons of dynamo systems at
> "http://nordicgroup.us/s78/dynamo.html".

Yes, we're familiar with that site. It claims to present an
"unbiased" evaluation of dynamo (or generator) lights, but somehow it
contains only every negative comment the author can dream up or
quote. It contains none of the positive comments repeatedly posted
here by people that routinely use bicycle dynamos with great success.

And, of course, the site still contains fundamental technical errors
that the author can't seem to understand. Let me spell one out - one
that I've hinted at many, many times. The table relating lumens to
watts has MR11 lamps and MR16 lamps with the same filament, judging by
the electrical data. But the MR16 are claimed to produce more than
twice as many lumens.

Anyone who understands the first fundamentals of optics knows that
lumens are a measuremen of the _total_ light output of a filament.
Wrapping a larger (MR16) reflector around the same filament cannot
change the total amount of light it produces. It can only change the
concentration of that light.

So we apparently have a light "expert" who is confused about the
fundamental units of measurement of light.

BTW, this same expert says http://myra-simon.com/bike/dynotest.html is
out of date because it does not include the Lightspin dynamo. Our
expert is apparently unaware that the Lightspin is no longer made,
meaning his own website is out of date. The Lightspin company
folded. It may resurrect itself, but odds don't look good at the
moment.

Finally, if one cherry picks enough other "experts" and takes enough
of their statements out of context, one can put together a list of
people who apparently don't like dynamos. But if the website were
truly unbiased, as the author claims, it would include an equal number
of statements from people like John Forester, Guy Chapman, Andreas
Ohler, John Allen, Sheldon Brown, Andrew Muzi, Peter Clinch and
countless others who either use, promote or accept generator lights.

Remember that SMS got into this as a failed marketer of rechargeable
light systems. Despite his claim to the contrary, his bias is
evident.

- Frank Krygowski
 
Prisoner at War wrote:

> Not arguing with you, Petey ol' boy (Goodness, no! LOL). Your points
> are well-taken. I had certainly investigated the SON dynamo for my HP
> Velo SMGTe initially. But for me -- and, I suspect, for most who are
> "fearless" enough to not bother with helmets and yet could still find
> the need at times for a headlight -- it's about the "YOOHOO!! I' over
> here!" factor that you get from a light bright as The Second Coming.

Please note I'm not saying more powerful battery lights are bad (I own a
set after all), just that it isn't a simple black and white "these are
good, these aren't" situation: both flavours have their relative
strengths and weaknesses, and both have proven useful and usable in the
Real World (TM).

One thing you'll need to consider on an SMGTe is where you'll mount the
lamps and batteries. It's certainly not impossible, but you can't just
assume a standard bar mount as typically supplied will work...

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/
 
SMS wrote:

> Again, this site is primarily to help people construct their own
> high-performance lighting systems. It's been expanded over the years to
> include information on other options, including a section that explains
> the pros and cons of dynamo systems at
> "http://nordicgroup.us/s78/dynamo.html".

As expected there's a lot of good info but it's clouded over by the
author's opinion that dynamos aren't really the thing, despite a few
million happy users out there.

"They're too expensive"... well, I've got expensive dynamos on my far
more expensive bikes, because I find the investment pays off for me.

"They're not powerful enough"... mine are powerful enough for long trips
on unlit roads in winter.

"High power battery setups are much better"... I have one, don't use it
any more as it's far more of a faff than the dynamos.

It's not as black and white as is being made out.

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/
 
Bill wrote:

> Give it time. HID lamps require a lot of drive electronics no matter
> what type they are, and LED lamps can be limited with a simple resistor,
> as is my Cateye with 5 LEDs.

The resistor limiting is very inefficient. The system used in the
inolight is probably a switching buck regulator with an efficiency of
well over 90%. When you're running on batteries or a dynamo you don't
want to be wasting power through resistors.

An active switching power supply could
> ensure better efficiency but would drive the cost of a $30 light to
> about $50,

Nah, the switchers are very cheap. In volume, about $1 for the IC, plus
maybe another $1 for the other components and PCB. It would drive the
final price up by maybe $5, in volume, but of course it's cheaper to not
bother and just have shorter battery life.

> I think LEDs will get bigger and
> better over time until they can take over the HID type.

Highly unlikely. Already, the heat problems of just the 5W LEDs are
severe. It's extremely difficult to transfer that much heat from the
junction to a heat sink.

HIDs are pretty cheap to make, it's just that they're a boutique item at
this time, so the auto manufacturers and after-market can charge a lot
for the. The ballast electronics are not anything high-tech, just a
smaller version of ballasts used in other types of high voltage lights.
 
SMS wrote:
> Prisoner at War wrote:
>> I'm wondering whether to get the Light & Motion ARC Li-Ion Ultra HID
>> or the NiteRider Moab HID/LED. They're both the same price but the
>> NiteRider burns over 50% longer at the same highest level of
>> brightness (if I'm reading the specs right -- in which case I'm
>> surprised Light & Motion haven't lowered their price at all; also, I'm
>> not sure what it means for the NiteRider to be "HID/LED" [according to
>> performancebike.com, anyway])....
>
> I've updated the HID/LED section of the Bicycle Lighting website
> "http://bicyclelighting.com". Note that this site was primarily a site
> for building homebrew lighting systems, not a site to evaluate every
> commercial lighting system on the market. As such, I've now included the
> TrailTech lamps because they are usable in a homebrew system, but not
> included the insanely over-priced commercial HID systems.
>
> I've also added the few good Luxeon LED lamps, since several readers
> requested this information, though the good LED lamps are nearly as
> expensive as the TrailTech HID lamps.
>
> The direct link to the HID/LED section is
> "http://nordicgroup.us/s78/hidled.html"
>
> Again, this site is primarily to help people construct their own
> high-performance lighting systems. It's been expanded over the years to
> include information on other options, including a section that explains
> the pros and cons of dynamo systems at
> "http://nordicgroup.us/s78/dynamo.html".

The TrailTech site indicates the MR11 light outputs 500lm at a power
draw of 13W. That's around the 40 lm/W of mature power LEDs like the
Luxeon. Newer LEDs, like the Cree, are capable of 80lm/W. Of course
that's at the 1W level, but it's still a lot of light for cycling.

LED systems have had difficulties scaling up, whereas HID systems have
difficulty scaling down. LEDs have finally reached the point in power
where they are beginning to qualify for huge application markets in
general & automotive lighting. Prices are declining fast. A 1W Cree is
currently at $7.50 in single units, Luxeons at half that.

A lot of people find the ~30-40lm of a generator powered incandescent
sufficient to ride by. Having used a wide variety of lights, I can't
imagine anyone really needing more than 200lm. The best of the latest
LED devices can almost do that today.

LEDs have a number of inherent advantages over both arc and incandescent
bulbs: more rugged/longer lived; ability to modulate power over a wide
range with no color shift or efficiency loss; simple power supplies; no
warm up; very small emitter/optics size; cheap to make in volume.

I don't think we'll ever see a HID light in the cycling "sweet spot" of
~200lm/2W.

2 years ago, I bought a NiteHawk 1W Luxeon light, MSRP $60. This year I
bought I 1W Luxeon head-mounted light for $15. I'm told they're
available for half that if you shop around. Prices have declined 4-5x
for the devices in that period. It's only a matter of time before LEDs
dominate all forms of lighting, including cycling.
 
Prisoner at War wrote:
> I'm wondering whether to get the Light & Motion ARC Li-Ion Ultra HID
> or the NiteRider Moab HID/LED. They're both the same price but the
> NiteRider burns over 50% longer at the same highest level of
> brightness (if I'm reading the specs right -- in which case I'm
> surprised Light & Motion haven't lowered their price at all; also, I'm
> not sure what it means for the NiteRider to be "HID/LED" [according to
> performancebike.com, anyway])....

While all the digression is interesting, I think your basic question is
still "which HID system should I buy?"

For a complete system I'd buy the TrailTech Single 13 W HID Helmet Light
with 14.8V 5.2Ah regulated Li-Ion Flat Pack + Smart Charger for $235,
with the 12 degree lamp.

See "http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3271"

This is a very good deal, in fact it's less than the less capable, and
less efficient Li-Ion Luxeon LED systems, and less than a Dymotec Dynamo
plus an Inolight inoled LED light.

Steve
http://bicyclelighting.com
 
I own one of the 30W Trail-Tech lights and several Topeak Moonshine
HIDs. The illumination from all of them is great. The 30W is brighter
than most of the mopeds I see on the road. However, durability is not
a quality of any of these lights. Within a year of use, they start to
have problems starting up or staying on. Also, the Trail-Tech light-
switch-battery set is very poorly manufactured. The wiring where the
switch line splices in to the battery-light line is just held together
with some heat shrink tubing (the Topeak has a plastic box over this
area to reduce flexing this weak joint). I've had to re-solder that
section. I do use my light every weekday, in the rain and over poorly
maintained asphalt trails, so I might be asking to much from them, but
as soon as LEDs reach the level of the 13W HIDs, I'll go back to LEDs.
 
tiborg wrote:
> I own one of the 30W Trail-Tech lights and several Topeak Moonshine
> HIDs. The illumination from all of them is great. The 30W is brighter
> than most of the mopeds I see on the road. However, durability is not
> a quality of any of these lights. Within a year of use, they start to
> have problems starting up or staying on. Also, the Trail-Tech light-
> switch-battery set is very poorly manufactured. The wiring where the
> switch line splices in to the battery-light line is just held together
> with some heat shrink tubing (the Topeak has a plastic box over this
> area to reduce flexing this weak joint). I've had to re-solder that
> section. I do use my light every weekday, in the rain and over poorly
> maintained asphalt trails, so I might be asking to much from them, but
> as soon as LEDs reach the level of the 13W HIDs, I'll go back to LEDs.

Most of the bicycle lighting systems require occasional wire
maintenance. On systems I make for my own use I use very good connectors
and switches designed for industrial use, but the commercial systems
never seem to want to go to the expense of higher quality connectors.

I like that there is no switch on the TrailTech lamp, as the integrated
switches are a big point of failure and should be avoided.
 
tiborg wrote:
> I own one of the 30W Trail-Tech lights and several Topeak Moonshine
> HIDs. The illumination from all of them is great. The 30W is brighter
> than most of the mopeds I see on the road. However, durability is not
> a quality of any of these lights. Within a year of use, they start to
> have problems starting up or staying on. Also, the Trail-Tech light-
> switch-battery set is very poorly manufactured. The wiring where the
> switch line splices in to the battery-light line is just held together
> with some heat shrink tubing (the Topeak has a plastic box over this
> area to reduce flexing this weak joint). I've had to re-solder that
> section. I do use my light every weekday, in the rain and over poorly
> maintained asphalt trails, so I might be asking to much from them, but
> as soon as LEDs reach the level of the 13W HIDs, I'll go back to LEDs.

This will probably occur with a multiple LED Luxeon lamp, but the beam
won't be as good because it's so difficult to collimate the light from
several sources into one beam.

The advantage of HID is that heat is easier to dissipate because it's
transfered over a wide area, through the glass. On the LED, it's the
very small semiconductor junction that heats up, and it's very difficult
to transfer so much heat through such a small surface area. Lumileds has
extensive information on designing heat sinks. Luxeon is working on is
designing LEDs that can have higher junction temperatures. Some high
intensity applications are adding active cooling fans, just like there
are fans to cool light sources in devices such as projectors.

There is one LED light, the Inolight, where the LED junction was so hot
that it was causing components on the printed circuit board to unsolder.
 
On May 3, 12:47 pm, [email protected] wrote:
>
>
> If you do go with some mega-bright, no-optics solution, please be
> courteous with it.
>
> Some of us have encountered cyclists with those systems approaching us
> on bike trails, and have experienced being blinded. Some users have
> bragged about car drivers flashing their brights, because of the glare
> from those systems.
>
> We don't need to get into lumen wars with other cyclists, or with car
> drivers. For road riding, you need enough light on the road to see
> the road, including potholes or trash. And you need enough light
> going above the road to make you as conspicuous as you are in the
> daytime, no more.
>
> Those purposes require relatively little light output. You don't need
> any more - and in particular, burning out people's retinas with
> excessive above-the-road light is, at best, pretty rude. At worst,
> it's dangerous for them and for you.
>
> That's one reason automotive headlights, motorcycle headlights, and
> well-designed bike headlights have a "cut-off" plane. Below that
> plane, light going to the road is bright. Above that plane, light
> going into others' eyes is much dimmer.
>
> If your lights don't have optics that produce that sort of beam
> pattern, please point them low enough to not blind other users.
> Don't become the lumen equivalent of a Hummer driver, putting your
> (supposed) safety and macho power above the safety of everyone else.
>
> - Frank Krygowski


Yes, that's a very important point you make. While I was certainly
relishing giving them motorists a bit of their own medicine with an
HID light, I also don't want my fellow cyclists to be blinded! I'm
not sure how they could be, though, seeing how they'd be at the same
eye-level as me...except for recumbent cyclists -- but then I really
plan on using the HID on my 'bent, so it'd be mounted lower than most
cyclists' vantage points, and even that of many cars, for that matter.

Not sure how I'd prevent their being blinded, anyway: I couldn't
predict it, could I? But I'm sure the two HIDs I'm considering have
some kind of optics which should mitigate such circumstances. They
better, anyway, for $600!!!

So which one do you recommend? Looks like the NiteRider is a winner.
Funny how I can't really find reviews of these guys online. I've seen
only one "real" (i.e., useful, with a good photo) review of the Light
& Motion product, but none yet for the NiteRider (which is newer,
though).

Anyway, a good reminder, your post. I almost never feel the need for
a light, but all club rides require them (except the anarchist Time's
Up! rides -- hooray!), and, in keeping with my nature, if I get
something I'd like to get the best. ^_^

(Yes yes I know "the best" is a semantically ambiguous term....)
(Yes yes, I know, "
 
Prisoner at War wrote:

> Yes, that's a very important point you make. While I was certainly
> relishing giving them motorists a bit of their own medicine with an
> HID light, I also don't want my fellow cyclists to be blinded! I'm
> not sure how they could be, though, seeing how they'd be at the same
> eye-level as me...except for recumbent cyclists -- but then I really
> plan on using the HID on my 'bent, so it'd be mounted lower than most
> cyclists' vantage points, and even that of many cars, for that matter.

Mounting on the front of a Streetmachine won't actually be that
much lower than a fork-crown mounting on a "normal" bike. More
important is which way it's pointing and how directed the optics are.

> Not sure how I'd prevent their being blinded, anyway: I couldn't
> predict it, could I? But I'm sure the two HIDs I'm considering have
> some kind of optics which should mitigate such circumstances. They
> better, anyway, for $600!!!

If it's not bright because of dissipating optics or because it just
isn't very powerful, it's still not very bright, and if your goal
is to be very bright... You can't have it both ways! Cars have
separate dip beams for a very good reason, because illuminating the
road as much as possible and illuminating the road to an adequate
degree while not blinding oncoming folk are not fully compatible
goals.

With this in mind, it'd be worth getting getting a set with a
switchable output. My recharageable set has twin heads, one 2.4W
and one 10W, and you can easily switch between either or both.
Something like that, and don't forget you are *not* safer if the
truck coming towards you is driven by someone who can't see
properly thanks to you wiping out his night vision...

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/
 
On May 6, 11:01 am, Prisoner at War <[email protected]> wrote:
> On May 3, 12:47 pm, [email protected] wrote:
>
> > If you do go with some mega-bright, no-optics solution, please be
> > courteous with it.
>
> > Some of us have encountered cyclists with those systems approaching us
> > on bike trails, and have experienced being blinded. Some users have
> > bragged about car drivers flashing their brights, because of the glare
> > from those systems.
> ...
>
> Yes, that's a very important point you make. While I was certainly
> relishing giving them motorists a bit of their own medicine with an
> HID light, I also don't want my fellow cyclists to be blinded! I'm
> not sure how they could be, though, seeing how they'd be at the same
> eye-level as me...

It absolutely can and will happen. I've been on the receiving end, on
a short cut-through bike trail in our town. I remember desperately
trying to shield my eyes and close one eye to retain a _little_ night
vision. It was ugly.

> Not sure how I'd prevent their being blinded, anyway: I couldn't
> predict it, could I? But I'm sure the two HIDs I'm considering have
> some kind of optics which should mitigate such circumstances. They
> better, anyway, for $600!!!

Wrong. They won't. Or more precisely, I'll be amazed if the beams
are anything other than circular - that is, sending exactly as much
light up as down. For some reason, manufacturers of $600 HID lights
(or $200 MR-16 lights) can't replicate the optics of a $20 Cateye
light from 1990.

The only way to NOT blind an oncoming cyclist with a no-optics high
power light, is to point the light down in front of you. But then
you'll find you've got a super-bright patch of road close in front of
you, it's reflecting back and ruining your night vision, and you can't
see very well at all. This is why I don't like the crude-optics mega-
lights.

Before you shell out the cost of a bicycle on an excessively bright
light, try this: Borrow an ordinary, good quality bike headlight.
Try a Cateye Halogen Micro-II, for example, if you can find one (the
pre-LED model) or any decent generator light. Put it on your bike,
have a friend ride your bike toward you, and see how conspicuous 2.4
watts of halogen light really is.

I've done this with dozens of other cyclists, in night lighting
workshops. I've never had any of them say "That's too dim to be
safe."

If you want to up the lumen output, that, fine. But be responsible,
and don't think you've got to look like a supernova to be noticed.

> So which one do you recommend?

I recommend a generator light. If you don't like to generate your own
power, I recommend a generator lamp powered by your own rechargeable
battery pack. If you want twice as much light, either put in a more
powerful bulb into the lamp assembly, or mount two of them.

- Frank Krygowski
 
Prisoner at War wrote:

> Anyway, a good reminder, your post. I almost never feel the need for
> a light, but all club rides require them (except the anarchist Time's
> Up! rides -- hooray!), and, in keeping with my nature, if I get
> something I'd like to get the best. ^_^

I'm glad to see more night rides by clubs. Some clubs are very explicit
as to the brightness of lights that are required, but any available HID
light should be sufficient, usually the minimum is a 6 watt
quartz-halogen headlight and some sort of an LED or xenon tail light.

With the HID and MR series of lights, you don't really have to worry
about blinding other cyclists, as the optics on these are very precise.
On some of the sealed beams the light is more of a flood pattern, and I
wouldn't use the 25 watt version in traffic as it could be annoying.
 
On May 7, 12:01 am, SMS <[email protected]> wrote:
> Prisoner at War wrote:
> > Anyway, a good reminder, your post. I almost never feel the need for
> > a light, but all club rides require them (except the anarchist Time's
> > Up! rides -- hooray!), and, in keeping with my nature, if I get
> > something I'd like to get the best. ^_^
>
> I'm glad to see more night rides by clubs. Some clubs are very explicit
> as to the brightness of lights that are required,

Oh? How do they measure brightness?

> but any available HID
> light should be sufficient, usually the minimum is a 6 watt
> quartz-halogen headlight...

"Usually"? I'd like to see some citation for that.

> With the HID and MR series of lights, you don't really have to worry
> about blinding other cyclists, as the optics on these are very precise.

>From what I've seen, the optics on HID and MR lights are very precise
only in that they don't throw light out the back! They do throw a fog
of light out the front, _roughly_ in an eight degree (fairly typical
spot) or 30+ degree (fairly typical flood) radially symmetrical
pattern. IOW they throw as much light up as down.

Compare this with the optics on, say, my car headlamps, my motorcycle
headlamps, or my bicycle generator headlamps. All these direct less
light upward, since more light is needed downward onto the road. The
cutoff plane is easily apparent. They use the light output
efficiently.

Remember, light going upward toward other road users travels directly
from your lamp to their eye. It doesn't need to be as powerful as
what goes down. The downward light must hit the road, where some gets
absorbed and some gets scattered. Only a small percentage bounces
back to your eye to show you the road.

You need bright light down, much less light up. Radially symmetrical
optics don't do that.

- Frank Krygowski
 
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