Best generator to power a light?

[Bruce W.1]

What's the best generator to power a headlight these days? My research
indicates that the ones that go in the hub are best but I'm not going to
do that. I'd prefer one that presses against the sidewall of the tire.

Last time I had one of these was over 30 years ago. I hope technology
has improved their efficiency because the one I had was a real drag and
substantially increased pedaling effort.

Does anybody here use a generator or are batteries the way to go?

My bike has 700C tires and I use it mostly for touring on roads.

I made some great lights with lithium battery packs, but I'd like to try
a generator again, if they have improved.

Thanks for your help.

 

[A Muzi]

Bruce W.1 wrote:

> What's the best generator to power a headlight these days? My research
> indicates that the ones that go in the hub are best but I'm not going to
> do that. I'd prefer one that presses against the sidewall of the tire.
>
> Last time I had one of these was over 30 years ago. I hope technology
> has improved their efficiency because the one I had was a real drag and
> substantially increased pedaling effort.
>
> Does anybody here use a generator or are batteries the way to go?
>
> My bike has 700C tires and I use it mostly for touring on roads.
>
> I made some great lights with lithium battery packs, but I'd like to try
> a generator again, if they have improved.
>
> Thanks for your help.
Well , they will slow you down by 2.5W plus whatever
inefficiency is in the dynamo.

As in so many things, I like them and have a dynamo on
nearly each of my bikes ( all but one).

Others eschew 'energy losses' and obsess over it and so
choose battery systems. There is no objective 'answer'.

Sony for example mixes systems to note that at 15kph, their
2.5W output adds a drag of 150g/cm with the light on and
116g/cm light off and compares with an XT rubber-seal hub at
80 g/cm.

Hope that helps.

BTW some of my dynamos have a total expense of a few bulbs
over 35 years. I never forget them at home. Those are
criteria too.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Chuck]

On 2005-06-27, A Muzi <[email protected]> wrote:
> Bruce W.1 wrote:
>
>> What's the best generator to power a headlight these days? My research
>> indicates that the ones that go in the hub are best but I'm not going to
>> do that. I'd prefer one that presses against the sidewall of the tire.
>>
>> Last time I had one of these was over 30 years ago. I hope technology
>> has improved their efficiency because the one I had was a real drag and
>> substantially increased pedaling effort.
>>
>> Does anybody here use a generator or are batteries the way to go?
>>
>> My bike has 700C tires and I use it mostly for touring on roads.
>>
>> I made some great lights with lithium battery packs, but I'd like to try
>> a generator again, if they have improved.
>>
>> Thanks for your help.
> Well , they will slow you down by 2.5W plus whatever
> inefficiency is in the dynamo.
>
> As in so many things, I like them and have a dynamo on
> nearly each of my bikes ( all but one).
>
> Others eschew 'energy losses' and obsess over it and so
> choose battery systems. There is no objective 'answer'.
>
> Sony for example mixes systems to note that at 15kph, their
> 2.5W output adds a drag of 150g/cm with the light on and
> 116g/cm light off and compares with an XT rubber-seal hub at
> 80 g/cm.
>
> Hope that helps.
>
Well, the thing about the battery to remember is you have light if you
get a flat at night.
> BTW some of my dynamos have a total expense of a few bulbs
> over 35 years. I never forget them at home. Those are
> criteria too.

 

[Helmut Springer]

Bruce W.1 <[email protected]> wrote:
> What's the best generator to power a headlight these days? My
> research indicates that the ones that go in the hub are best but
> I'm not going to do that. I'd prefer one that presses against the
> sidewall of the tire.

If you're going for longer distances or bad weather conditions you
might want to rethink...


> Does anybody here use a generator or are batteries the way to go?

Hub generator. From own experience and some discussons that is the
main improvement in generators. Most material I'm aware of is in
German though...

http://www.peterwhitecycles.com/lightingsystems.htm is pretty good
(as Petr's website in general).

--
MfG/Best regards
helmut springer

 

[Ron Hardin]

I go with a bike trailer carrying a Honda EU2000i 1600w generator
(only 40 lbs!). Then you can just use ordinary table lamps, too.

--
Ron Hardin
[email protected]

On the internet, nobody knows you're a jerk.

 

[Ron Hardin]

A Muzi wrote:
> Sony for example mixes systems to note that at 15kph, their
> 2.5W output adds a drag of 150g/cm with the light on and
> 116g/cm light off and compares with an XT rubber-seal hub at
> 80 g/cm.

I don't understand the units. If it's a force, you'd expect g cm/sec^2.
If it's a power, you'd expect force . velocity = g cm^2/sec^3.

g/cm seems to be force / velocity^2

though I am always screwed up by whether people might mean newtons
or grams sort of interchangeably, which comes from reading forces
(quite reasonably) off scales but always leaves you wondering whether
32 ft/sec^2 ought to be thrown in or not when confronting a formula,
with a correpsonding bafflement about units.
--
Ron Hardin
[email protected]

On the internet, nobody knows you're a jerk.

 

[dvt]

Ron Hardin wrote:
> ...I am always screwed up by whether people might mean newtons
> or grams sort of interchangeably, which comes from reading forces
> (quite reasonably) off scales but always leaves you wondering whether
> 32 ft/sec^2 ought to be thrown in or not when confronting a formula,
> with a correpsonding bafflement about units.

This baffles me as well. Although I think it's worse in English units,
where a pound is the term for both mass and force. It's much nicer if
they put the little "f" at the end -- lbf or kgf instead of lb or kg.

--
Dave
dvt at psu dot edu

 

[Andy M-S]

The only thing I can say is, reconsider the hub generator! I have one
of the newer Shimano units (DH-N370, I think) and it's pretty much
flawless. It has all of the advantages of a friction generator, save
that it can't be mechanically isolated (but the drag is trivial), and
none of the disadvantages.

I went to this system after using a generator lighthead with Li-Ion
packs for a while, and I'm very happy that I did. I never need to
worry about charging batteries anymore.

 

[[email protected]]

Bruce W.1 wrote:
> What's the best generator to power a headlight these days? My research
> indicates that the ones that go in the hub are best but I'm not going to
> do that. I'd prefer one that presses against the sidewall of the tire.
>
> Last time I had one of these was over 30 years ago. I hope technology
> has improved their efficiency because the one I had was a real drag and
> substantially increased pedaling effort.
>
> Does anybody here use a generator or are batteries the way to go?
>
> My bike has 700C tires and I use it mostly for touring on roads.
>
> I made some great lights with lithium battery packs, but I'd like to try
> a generator again, if they have improved.

First, a good source of information is
http://www.myra-simon.com/bike/dynotest.html

The info is a couple years old, but mostly still good. One notable
change is that the Shimano hub generators have had their efficiency
improved.

The "best" generator, according to anyone who's tried one, is the SON
(or Schmidt) hub generator. In general, hub generators do better
because they spin at a lower speed (less friction and windage losses)
and have no friction losses between the generator roller and the tire.
Apparently this is a surprisingly large source of drag. However, they
are more expensive than other generators and do require rebuilding a
wheel, so they require some commitment. Beware of ones that have
internal gearing to increase the rotor speed. They have a bad
reputation.

Personally, I have several copies of old Soubitez bottom-bracket
generators. They must be nearly 20 years old. They work perfectly
well, and the drag is in no way objectionable. They'll knock a riding
speed of 19 mph down to about 17.5 or 18 mph, which is fine for me.

I've also used the FER 2002, a unique spoke-driven unit that mounts by
sliding over the front axle, between the hub and the front fork. A
plastic lever flips into the spokes and drives an internal cogged belt
and gear system to spin the generator. It looks amazingly cheap and
clunky, and I've heard of others breaking belts, but it has less drag
than sidewall or bottom bracket generators, and (like hub generators)
will never slip in mud, snow, etc.


If you want to get lost tracking down links on generators, etc,
http://www.nscl.msu.edu/~daniel/regulator.html will keep you busy.
Also, there's a discussion group titled Bikecurrent where generators
are regularly discussed.

- Frank Krygowski

 

[David Damerell]

Quoting Bruce W.1 <[email protected]>:
>What's the best generator to power a headlight these days? My research
>indicates that the ones that go in the hub are best but I'm not going to
>do that. I'd prefer one that presses against the sidewall of the tire.
>Last time I had one of these was over 30 years ago. I hope technology
>has improved their efficiency because the one I had was a real drag and
>substantially increased pedaling effort.

Bottle dynamos have improved enormously, but it is odd that you do not
want to use a hub dynamo. They typically have lower drag than bottle
dynamos.

>Does anybody here use a generator or are batteries the way to go?

I do, yes, and I think the reliability of the dynamo is enormously
superior to battery lights.
--
David Damerell <[email protected]> flcl?
Today is First Tuesday, Presuary.

 

[Frank Miles]

In article <[email protected]>,
Ron Hardin <[email protected]> wrote:
>I go with a bike trailer carrying a Honda EU2000i 1600w generator
>(only 40 lbs!). Then you can just use ordinary table lamps, too.

Good one! Now... does the 40lbs include the weight of the gasoline...?

-frank
--

 

[[email protected]]

Re-think. The sidewall dynamos (a) have high drag, (b) are rough on
your sidewalls, and (c) have problems with traction if it is wet, esp.
if it is wet and icy/snowy. I used to have one on my old Schwinn
Continental, which I used for commuting even in snowy conditions ...
but it sucked and the current ones still have the same issues. I
re-thought, and now run hub generators - drag is imperceptible, they do
not chew up my tires, and there are no traction problems in any kind of
weather.

- rick

 

[Benjamin Lewis]

[email protected] wrote:

> Re-think. The sidewall dynamos (a) have high drag, (b) are rough on
> your sidewalls, and (c) have problems with traction if it is wet, esp.
> if it is wet and icy/snowy. I used to have one on my old Schwinn
> Continental, which I used for commuting even in snowy conditions ...
> but it sucked and the current ones still have the same issues. I
> re-thought, and now run hub generators - drag is imperceptible, they do
> not chew up my tires, and there are no traction problems in any kind of
> weather.

I believe there are some, e.g. Litespin, that are significantly more
efficient than older units, and according to some tests are even better
(more efficient, anyway) than hub dynamos, including the SON. I haven't
looked at the testing methodology.

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then suddenly it flips
over, pinning you underneath. At night, the ice weasels come."
--Matt Groening

 

[m-gineering]

Benjamin Lewis wrote:

>
> I believe there are some, e.g. Litespin, that are significantly more
> efficient than older units, and according to some tests are even better
> (more efficient, anyway) than hub dynamos, including the SON. I haven't
> looked at the testing methodology.


ISTRT early versions used a weak spring, which gave very good efficiency
in the dry.

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

 

[[email protected]]

A Muzi wrote:

>Sony for example mixes systems to note that at 15kph, their
>2.5W output adds a drag of 150g/cm with the light on and
>116g/cm light off and compares with an XT rubber-seal hub at
>80 g/cm.

I have never seen a Sony dynamo, must be a Japanese-only product. I
have dynamos from Union (Marwi), and Sanyo. The Marwi dynamo I bought
from the Third Hand, and haven't been able to mount on my foldng
bicycle, but these tire dynamos do result in very noticable drag. I'm
thinking of getting a hub dynamo, but it'll cost just about $100 for
the dynamo, then I have to rebuild the wheel with it.

I'm now using a rechargeable Li-Ion flashlight mounted with a lock
block, which has a big advantage over NiMH powered lights, because the
self-discharge rate of Li-Ion cells is very low.

 

[[email protected]]

Fixed font - Proportional font


Best generator to power a light?
All 14 messages in topic - view as tree
Bruce W.1 Jun 26, 7:27 pm show options

Bruce W.1 wrote:

> What's the best generator to power a headlight these days?

The best tire generator is the Swiss LightSPIN,
"http://www.yellowjersey.org/litespin.html"

For more information on dynamo powered lights, you can go directly to
the dynamo section at "http://nordicgroup.us/s78/dynamo.html"

 

[[email protected]]

[email protected] wrote:
>
>
> The best tire generator is the Swiss LightSPIN,
> "http://www.yellowjersey.org/litespin.html"
>
> For more information on dynamo powered lights, you can go directly to
> the dynamo section at "http://nordicgroup.us/s78/dynamo.html"

<Sigh>

Of course, visit that site. But understand that it is written by the
man who is Usenet's most confirmed slanderer of generator lights!

I see he's re-written parts of the site - indicating he is learning -
but the overall message is still the same:

Scharf still claims a decent generator set costs hundreds of dollars -
despite the millions of inexpensive sets in use around the world for
decades.

He still claims generator sets are adequate only for low-speed riding -
despite the popularity of high-quality generators for non-stop 600 km
Audax rides.

He still claims "the experts" advise against generator sets - despite
their endorsement or acceptance by people from John Forester to Sheldon
Brown to every Department of Transportation in the US.

There are many Usenet denizens who have used generators for decades,
for all sorts of riding. There are those like myself who have switched
to the high powered rechargeable lights like those Scharf used to sell,
but given them up for the greater convenience and practicality of
generators.

To be sure, batteries are getting better. And someday, high powered
bike lights may even have decent optics, as generator lights do now!
But a well-chosen generator, properly installed, will always be a
perfectly reasonable choice for the road cyclist interested in
practical, reliable lighting.

- Frank Krygowski

 

[[email protected]]

Bruce W.1 wrote:
> What's the best generator to power a headlight these days? My research
> indicates that the ones that go in the hub are best but I'm not going to
> do that. I'd prefer one that presses against the sidewall of the tire.
>
> Last time I had one of these was over 30 years ago. I hope technology
> has improved their efficiency because the one I had was a real drag and
> substantially increased pedaling effort.
>
> Does anybody here use a generator or are batteries the way to go?
>
> My bike has 700C tires and I use it mostly for touring on roads.
>
> I made some great lights with lithium battery packs, but I'd like to try
> a generator again, if they have improved.

Google "dynamo lights bicycle." The first two results are for Peter
White Cycles. They sell the good quality dynamos and lights, though
they don't sell the Litespin, which is the best tire driven dynamo.

The third and fourth results are two of my pages, one of which attempts
to dispel the the myths about battery powered lights, and one which
explains the facts about dynamo powered lights. Personally I use both
kinds of lights, and each has their good and bad attributes. I added a
table of the available high end lamps for dynamos, since I couldn't
find such a comparison anywhere else.

Definitely check out "http://www.yellowjersey.org/" for the Litespin,
as well as for some lower cost alternatives.

While a hub dynamo is usually the best, and most expensive, option,
something like the Litespin would still be pretty good. With a Litespin
and some of the lights from Peter White Cycles, you could come in at a
little under $200 for a very good system.

 

[[email protected]]

[email protected] wrote:
> With a Litespin
> and some of the lights from Peter White Cycles, you could come in at a
> little under $200 for a very good system.

True. And if you, like most non-competitive cyclists, were willing to
accept drag equivalent to riding ten feet uphill in a mile (see the
drag graph, the second graph at
http://www.myra-simon.com/bike/dynotest.html) you could get a much more
ordinary generator. Consider the AXA, for example. Here's a mail
order source: http://www.sjscycles.com/store/vIndex.htm?cat117.htm
That generator has a good reputation.

You'll need to add a headlight, of course. Like anything else, they
vary in cost and quality, with the usual diminishing returns.
http://www.sjscycles.com/store/vIndex.htm?cat117.htm

In practice, unless you plan to compete (say, riding brevets) you can
get a very good system for less than $50. And BTW, I have a friend who
rode 300+ miles in 24 hours when he was in his early 70s. He did the
night portion of the ride with this Union generator:
http://tinyurl.com/ch99t

In other words, don't let anyone tell you that you must spend hundreds
of dollars to light your way.

- Frank Krygowski