Lights

Jasper Janssen said:

Quoted message said:

None were anywhere near $100 (although the FER was a
closeout). All give very good light and very good reliability. All
have lasted for many years.

http://www.roseversand.com/rose_main.cfm?KAT_ID=0&PRD_ID=15926&spr_id=2&MID=0&CID=175

FER is currently 25 EUR or around US$30.

Jasper

Really!

Seriously, I think I paid $40 on it from a shop that was going out of
business. IIRC, they were selling it for near $100! At $30, I'd
recommend it.

Understand, it's a quirky unit. It's driven by the front wheel's
spokes, and it mounts between the front fork and hub, by sliding the
axle through a hole in the unit. (Somehow, this doesn't work well on
my commuting bike, but it's fine on my wife's touring bike.) It's got
a two-stage speed increase from the spoke driver to the generator, by a
plastic gearset and a tiny toothed timing belt. And the unit is big,
kind of heavy, and decidedly clunky looking.

But it _is_ efficient, quite a bit more than either a typical bottle or
bottom bracket generator. And the headlight that comes it has very
good optics indeed. If you can put up with the quirky looks and
weight, I think it's worth a try. I'd buy it over a Union bottle
generator in a second.

- Frank Krygowski

Jasper Janssen said:

... a bottle generator, they're around 35-40% efficient
for the good ones. About Half of that is the tyre/generator interface and
the rest is frictional and electric losses.

Jasper, do you know anything about bottle generators running on the
rim's braking surface? I saw one once, and it struck me that it might
reduce that first type of loss.

- Frank Krygowski

In article <[email hidden]>,

Quoted message said:

Jasper Janssen said:

... a bottle generator, they're around 35-40% efficient
for the good ones. About Half of that is the tyre/generator interface and
the rest is frictional and electric losses.

Jasper, do you know anything about bottle generators running on the
rim's braking surface? I saw one once, and it struck me that it might
reduce that first type of loss.

My current sidewall-driven unit is fairly new, and it inflicts
much less drag than the venerable old Union bottle generators.
And that's after replacing the stock, soft rubber drivewheel
with a metal one off an old Union unit. It purrs along like
a contented kitten. And that's just a MOR bottle generator
that cost about $28.

cheers,
Tom

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Quoted message said:

Jasper Janssen said:

Quoted message said:

None were anywhere near $100 (although the FER was a
closeout). All give very good light and very good reliability. All
have lasted for many years.

http://www.roseversand.com/rose_main.cfm?KAT_ID=0&PRD_ID=15926&spr_id=2&MID=0&CID=175

FER is currently 25 EUR or around US$30.

Quoted message said:

Seriously, I think I paid $40 on it from a shop that was going out of
business. IIRC, they were selling it for near $100! At $30, I'd
recommend it.

Understand, it's a quirky unit. It's driven by the front wheel's
spokes, and it mounts between the front fork and hub, by sliding the
axle through a hole in the unit. (Somehow, this doesn't work well on
my commuting bike, but it's fine on my wife's touring bike.) It's got
a two-stage speed increase from the spoke driver to the generator, by a
plastic gearset and a tiny toothed timing belt. And the unit is big,
kind of heavy, and decidedly clunky looking.

Given that they're selling spare belts in two lengths, I suspect that the
current version is a two belt system rather than one belt and one plastic
gearset.

Quoted message said:

But it _is_ efficient, quite a bit more than either a typical bottle or
bottom bracket generator. And the headlight that comes it has very
good optics indeed. If you can put up with the quirky looks and
weight, I think it's worth a try. I'd buy it over a Union bottle
generator in a second.

Ah. I do not believe this version comes with a headlight. This may account
for some of the difference in price. It's a standard 6V/3W unit though, so
all standard generator headlights should work.

Jasper

On Tue, 11 Oct 2005 18:55:50 -0700, [email hidden] (Tom Keats)

Quoted message said:

In article <[email hidden]>,

Jasper Janssen said:

On Wed, 14 Sep 2005 17:48:54 -0700, [email hidden] (Tom Keats)

Quoted message said:

Even the antiquated Union U-100 headlights (which I'm
currently using) have superior optics to any flashlight's.

If only because flashlights are *designed* to have a beam that's much
narrower than what you need on a bike.

Those hi-powered, MR-whatever-bulbed lights pretty much
have the same [lack of] optics as flashlights.

Well, if the headlight's light blinds you to whatever's out of the beam,
it's too powerful anyway.

Jasper

Quoted message said:

Jasper Janssen said:

... a bottle generator, they're around 35-40% efficient
for the good ones. About Half of that is the tyre/generator interface and
the rest is frictional and electric losses.

Jasper, do you know anything about bottle generators running on the
rim's braking surface? I saw one once, and it struck me that it might
reduce that first type of loss.

I've never seen one in person, but yeah, I would imagine that a solid
rubber wheel on alu rim surface would cause less losses than a tyre-driven
bottle. On the other hand, performance in the rain.. bottle dynamos
already have a bit of a tendency to slip when wet, after all.

Jasper

Jasper Janssen <[email hidden]> sd / msg
<[email hidden]> dtd Sat, 15 Oct 2005
00:52:58 GMT:

Quoted message said:

I've never seen one in person, but yeah, I would imagine that a solid
rubber wheel on alu rim surface would cause less losses than a tyre-driven
bottle. On the other hand, performance in the rain.. bottle dynamos
already have a bit of a tendency to slip when wet, after all.

Yes, I think that's likely. You can get wet-use wheels for some
bottle dynamos (they are like wire brushes I think). But in the end a
bottom bracket or (best of all ) hub is likely to be better.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

85% of helmet statistics are made up, 69% of them at CHS, Puget Sound

In article <[email hidden]>,

Just zis Guy said:

Jasper Janssen <[email hidden]> sd / msg
<[email hidden]> dtd Sat, 15 Oct 2005
00:52:58 GMT:

Quoted message said:

I've never seen one in person, but yeah, I would imagine that a solid
rubber wheel on alu rim surface would cause less losses than a tyre-driven
bottle. On the other hand, performance in the rain.. bottle dynamos
already have a bit of a tendency to slip when wet, after all.

Yes, I think that's likely. You can get wet-use wheels for some
bottle dynamos (they are like wire brushes I think). But in the end a
bottom bracket or (best of all ) hub is likely to be better.

I've got a relatively new bottle generator (purchased last
January) and it has no slipping-when-wet issues at all.
I've even purposely ridden through puddles to see if it
would slip.

However I've gone through some previously-owned
bottle generators that eventually did start
slipping in the rain, but that was after a /lot/
of use.

So I consider the slipping problem might not be
intrinsic to the drivewheel/tire interface, but
rather develops from some sort of internal wear.
I've noticed how these units do fling a lot of
muck around when used in the rain (as evidenced
by the buildup on the near brake arm.) I wouldn't
be surprised if little gritty particles eventually
managed to also work their ways inside the unit,
causing wear which eventually allows enough moisture
inside as well, to cause intermittent (i.e: in wet
conditions) shorts, and giving the impression
of slippage.

So bottle generators aren't immortal. But for
their low cost, one can still get a lot of good
use out of them. Even in the rain.

cheers,
Tom

--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca

Tom Keats said:

I've got a relatively new bottle generator (purchased last
January) and it has no slipping-when-wet issues at all.
I've even purposely ridden through puddles to see if it
would slip.

However I've gone through some previously-owned
bottle generators that eventually did start
slipping in the rain, but that was after a /lot/
of use.

So I consider the slipping problem might not be
intrinsic to the drivewheel/tire interface, but
rather develops from some sort of internal wear.

It's been decades since I used a bottle generator very much. I
switched to mostly bottom bracket models back around 1978, I think.

But I note that the Union models I've got downstairs have a cylindrical
roller, with serrations of course.

I recall the oft-noted fact that bike tires need no tread sipes, since
the toroidal shape of a smooth tire "parts the waters" on the road.
Applying this logic to a generator's drive wheel, ISTM a toroidal shape
would likely do better than a cylindrical shape.

I once planned to modify a Union drive wheel by machining a slot for a
heavy O-ring, and trying that on the rim's braking surface. But it's
probably going to stay on the far back burner for another year.

- Frank Krygowski

Quoted message said:

I've noticed how these units do fling a lot of
muck around when used in the rain (as evidenced
by the buildup on the near brake arm.) I wouldn't
be surprised if little gritty particles eventually
managed to also work their ways inside the unit,
causing wear which eventually allows enough moisture
inside as well, to cause intermittent (i.e: in wet
conditions) shorts, and giving the impression
of slippage.

So bottle generators aren't immortal. But for
their low cost, one can still get a lot of good
use out of them. Even in the rain.

cheers,
Tom

--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca

[email hidden] (Tom Keats) sd / msg
<[email hidden]> dtd Sat, 15 Oct 2005 10:44:47 -0700:

Quoted message said:

I've got a relatively new bottle generator (purchased last
January) and it has no slipping-when-wet issues at all.
I've even purposely ridden through puddles to see if it
would slip.

What model? We have the problem with a newish B&M on my wife's bike.
Admittedly it's been adjusted so as not to exert too much pressure,
maybe I've been a bit too cautious there. On the other hand if the
pressure is too great it shreds the rubber generator wheels!

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

85% of helmet statistics are made up, 69% of them at CHS, Puget Sound

Jasper Janssen said:

On Wed, 14 Sep 2005 17:48:54 -0700, [email hidden] (Tom Keats)

Quoted message said:

Even the antiquated Union U-100 headlights (which I'm
currently using) have superior optics to any flashlight's.

If only because flashlights are *designed* to have a beam that's much
narrower than what you need on a bike.

It depends on the flashlight. Many of the higher end flashlights have
optics that can adjust the beam from spot to flood, as needed.

The MR series of matched bulbs/reflectors are more efficient, but not
adjustable. Often you'll see a dual lamp arrangement, with one spot and
one flood, which also provides some redundancy.

SMS <[email hidden]> sd / msg
<[email hidden]> dtd Sun, 16 Oct 2005 03:45:16
GMT:

Quoted message said:

It depends on the flashlight. Many of the higher end flashlights have
optics that can adjust the beam from spot to flood, as needed.

But still a rotationally symmetrical beam, which means lots of wasted
light and a danger of causing dazzle to oncoming traffic at high
brightness (which is why no OEM car lights have rotationally
symmetrical optics).

Quoted message said:

The MR series of matched bulbs/reflectors are more efficient, but not
adjustable. Often you'll see a dual lamp arrangement, with one spot and
one flood, which also provides some redundancy.

And again, rotationally symmetrical. I guess in the decorative
lighting for which these were originally designed, that is not an
issue :-) And of course it's fine for offroad use.

But Frank's right, even quite ancient dynamo lamps have better optics.
The best optics of any bike lamp, for road use, are probably those of
the old Bisy FL, now sold as the SON E6.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

85% of helmet statistics are made up, 69% of them at CHS, Puget Sound