Roller dynamo slippage problem

On Tue, 03 Apr 2012 08:29:07 +1000, James wrote:

I've never noticed my Sanyo Dynapower roller dynamo slip in wet weather.
AFAIK, the light is always on while the dynamo is on the tyre and the
wheels are turning at a little faster than walking pace.


snip

I experienced significant slippage in wet weather to the point that I
replaced it with the Soubitez equivalent. The Sanyo had a very light
spring whereas the Soubitez' was much stronger.

Sanyo's light spring also meant it would bounce off the tire whenever I
went over bumps. Sometimes the bounce was so great that it would snap
back and engage the stop. Like others, I cured this by using rubber bands
to get more pressure against the tire.

Sanyo has upgraded its classic Dynapower bottom bracket generator with
the NH-T10 model.

http://www.peterwhitecycles.com/sanyo.asp

I installed one, along with modern LED lights. The dynamo appears to
eliminate all the problems with the old model. There is a rubber covering
for the roller wheel that eliminates slippage and the spring is much
stronger. Also, the LED lights come to full brightness at only 1 watt so
there much less effort is required. This also reduces slippage.

Stephen Bauman

On Apr 3, 4:56 am, Stephen Bauman wrote:
On Tue, 03 Apr 2012 08:29:07 +1000, James wrote:
I've never noticed my Sanyo Dynapower roller dynamo slip in wet weather.
AFAIK, the light is always on while the dynamo is on the tyre and the
wheels are turning at a little faster than walking pace.

snip

I experienced significant slippage in wet weather to the point that I
replaced it with the Soubitez equivalent. The Sanyo had a very light
spring whereas the Soubitez' was much stronger.

Sanyo's light spring also meant it would bounce off the tire whenever I
went over bumps. Sometimes the bounce was so great that it would snap
back and engage the stop. Like others, I cured this by using rubber bands
to get more pressure against the tire.

Sanyo has upgraded its classic Dynapower bottom bracket generator with
the NH-T10 model.

http://www.peterwhitecycles.com/sanyo.asp

I installed one, along with modern LED lights. The dynamo appears to
eliminate all the problems with the old model. There is a rubber covering
for the roller wheel that eliminates slippage and the spring is much
stronger. Also, the LED lights come to full brightness at only 1 watt so
there much less effort is required. This also reduces slippage.


http://en.wikipedia.org/wiki/Rube_Goldberg

On 03/04/12 21:56, Stephen Bauman wrote:
On Tue, 03 Apr 2012 08:29:07 +1000, James wrote:

I've never noticed my Sanyo Dynapower roller dynamo slip in wet weather.
AFAIK, the light is always on while the dynamo is on the tyre and the
wheels are turning at a little faster than walking pace.


snip

I experienced significant slippage in wet weather to the point that I
replaced it with the Soubitez equivalent. The Sanyo had a very light
spring whereas the Soubitez' was much stronger.

Sanyo's light spring also meant it would bounce off the tire whenever I
went over bumps. Sometimes the bounce was so great that it would snap
back and engage the stop. Like others, I cured this by using rubber bands
to get more pressure against the tire.

I've never had that problem, but mine is not mounted at the BB, rather
in front of the rear brake bridge. As a result it falls on to the wheel
rather than away from it.

Sanyo has upgraded its classic Dynapower bottom bracket generator with
the NH-T10 model.

http://www.peterwhitecycles.com/sanyo.asp

Yes, I've looked at that. Does it still damage the paint? Must you use
a cable to engage it? How does it latch on and release? Can you
lubricate the plain bearings?

I installed one, along with modern LED lights. The dynamo appears to
eliminate all the problems with the old model. There is a rubber covering
for the roller wheel that eliminates slippage and the spring is much
stronger. Also, the LED lights come to full brightness at only 1 watt so
there much less effort is required. This also reduces slippage.

The reduced wattage I can go along with. Perhaps that's another reason
I haven't had mine slip. Although, I would have thought the power
consumption was close to 3W with my setup. It is a little difficult to
calculate because the voltage and current waveforms are not so
sinusoidal when powering a bridge of LEDs.

--
JS.

On Wed, 04 Apr 2012 11:00:03 +1000, James wrote:

snip


Sanyo has upgraded its classic Dynapower bottom bracket generator with
the NH-T10 model.

http://www.peterwhitecycles.com/sanyo.asp

Yes, I've looked at that. Does it still damage the paint? Must you use
a cable to engage it? How does it latch on and release? Can you
lubricate the plain bearings?


The body is still electrically connected to the dynamo. However, they
also have two wires connected. So, one can tape the mounting to protect
the paint and still have a solid electrical connection.

A (bowdin) cable connection is required to disengage this model. The
cable ends in a lever that must be mounted on the frame. The supplied
clamp was too small for any tube on my bike. What I did was use a Zefel
water bottle cage boss for mounting. The actuating lever action resembles
a downtube shifter. It's enclosed. There's a pin that engages the lever
when the dynamo is not engaged. This provides a positive lock.

The literature indicates that sealed bearings are used and can be
replaced easily. I've not tried this yet.


I installed one, along with modern LED lights. The dynamo appears to
eliminate all the problems with the old model. There is a rubber
covering for the roller wheel that eliminates slippage and the spring
is much stronger. Also, the LED lights come to full brightness at only
1 watt so there much less effort is required. This also reduces
slippage.

The reduced wattage I can go along with. Perhaps that's another reason
I haven't had mine slip. Although, I would have thought the power
consumption was close to 3W with my setup. It is a little difficult to
calculate because the voltage and current waveforms are not so
sinusoidal when powering a bridge of LEDs.

The B&M LED lights (head and tail) pack quite a bit of electronics and
optics in them. I'm an EE by profession. I made a build/buy decision that
I'd be hard pressed to duplicate the their performance for less than the
$100 selling price for the front light. I'm getting a fairly well shaped
beam pattern as well as a standlight for the money.

Stephen Bauman

Stephen Bauman wrote:


The B&M LED lights (head and tail) pack quite a bit of electronics and
optics in them. I'm an EE by profession.

I admire B&M's optics. They've done a good job. Their optical
efficiency is hard to duplicate using the tools in my basement!

Regarding electronics: I'm an ME (retired) so not as competent as you
with electronics. But I'm curious about the specifics of the
electronics in those lights. My curiosity comes from the fact that the
critical parameter for an LED is current, and bike generators are
essentially constant current devices, 0.5 Amp. Obviously, there's need
for rectification, and for a capacitor if you want a standlight. But
what else are B&M doing in there?

It seems many home brewers (like James) are doing fine just with
rectification, or just using multiple LEDs to handle the different
phases of the AC waveform. So what else is needed?

--
- Frank Krygowski

On 4/4/2012 12:14 PM, Frank Krygowski wrote:
Stephen Bauman wrote:


The B&M LED lights (head and tail) pack quite a bit of electronics and
optics in them. I'm an EE by profession.

I admire B&M's optics. They've done a good job. Their optical efficiency
is hard to duplicate using the tools in my basement!

Regarding electronics: I'm an ME (retired) so not as competent as you
with electronics. But I'm curious about the specifics of the electronics
in those lights. My curiosity comes from the fact that the critical
parameter for an LED is current, and bike generators are essentially
constant current devices, 0.5 Amp. Obviously, there's need for
rectification, and for a capacitor if you want a standlight. But what
else are B&M doing in there?

It seems many home brewers (like James) are doing fine just with
rectification, or just using multiple LEDs to handle the different
phases of the AC waveform. So what else is needed?


Buck/boost regulators from China are commonly available for $3 retail
in that wattage.

They charge a lot of $$ for a bit of plastic and cheap electronics, but
that's the bike biz.

Frank Krygowski wrote:

Stephen Bauman wrote:

The B&M LED lights (head and tail) pack quite a bit of electronics and
optics in them. I'm an EE by profession.

I admire B&M's optics. *They've done a good job. *Their optical
efficiency is hard to duplicate using the tools in my basement!

Good thing you don't have to, and at a nominal 3W generator output
there are good reasons not to!

Chalo

On Apr 4, 2:12*pm, Peter Cole wrote:
On 4/4/2012 12:14 PM, Frank Krygowski wrote:









Stephen Bauman wrote:

The B&M LED lights (head and tail) pack quite a bit of electronics and
optics in them. I'm an EE by profession.

I admire B&M's optics. They've done a good job. Their optical efficiency
is hard to duplicate using the tools in my basement!

Regarding electronics: I'm an ME (retired) so not as competent as you
with electronics. But I'm curious about the specifics of the electronics
in those lights. My curiosity comes from the fact that the critical
parameter for an LED is current, and bike generators are essentially
constant current devices, 0.5 Amp. Obviously, there's need for
rectification, and for a capacitor if you want a standlight. But what
else are B&M doing in there?

It seems many home brewers (like James) are doing fine just with
rectification, or just using multiple LEDs to handle the different
phases of the AC waveform. So what else is needed?

Buck/boost regulators from China are commonly available for $3 retail
in that wattage.

They charge a lot of $$ for a bit of plastic and cheap electronics, but
that's the bike biz.

But why would they need a regulator at all? My point is, bike dynamos
are naturally constant current, and they put out pretty close to 0.5
Amp rms. That seems a useful value in the high powered LEDs I've seen
and used, with only rectification needed. So why regulate something
that's already constant?

Again, I'm not an EE, so please feel free to tell me what I'm missing.

- Frank Krygowski

On Apr 4, 2:27*pm, Chalo wrote:
Frank Krygowski wrote:

Stephen Bauman wrote:

The B&M LED lights (head and tail) pack quite a bit of electronics and
optics in them. I'm an EE by profession.

I admire B&M's optics. *They've done a good job. *Their optical
efficiency is hard to duplicate using the tools in my basement!

Good thing you don't have to, and at a nominal 3W generator output
there are good reasons not to!

?

I've built a couple LED headlights. Although I'm not positive, I
suspect the total lumen output of my home brews is the same as that of
the IQ Cyo I own. But the Cyo will light up a stop sign nearly 1/4
mile away, and beautifully light the road at the same time. The home
brews don't do the same. If I could duplicate those optics, I
certainly would.

- Frank Krygowski

On 4/4/2012 2:37 PM, Frank Krygowski wrote:
On Apr 4, 2:12 pm, Peter wrote:
On 4/4/2012 12:14 PM, Frank Krygowski wrote:









Stephen Bauman wrote:

The B&M LED lights (head and tail) pack quite a bit of electronics and
optics in them. I'm an EE by profession.

I admire B&M's optics. They've done a good job. Their optical efficiency
is hard to duplicate using the tools in my basement!

Regarding electronics: I'm an ME (retired) so not as competent as you
with electronics. But I'm curious about the specifics of the electronics
in those lights. My curiosity comes from the fact that the critical
parameter for an LED is current, and bike generators are essentially
constant current devices, 0.5 Amp. Obviously, there's need for
rectification, and for a capacitor if you want a standlight. But what
else are B&M doing in there?

It seems many home brewers (like James) are doing fine just with
rectification, or just using multiple LEDs to handle the different
phases of the AC waveform. So what else is needed?

Buck/boost regulators from China are commonly available for$3 retail
in that wattage.

They charge a lot of $$ for a bit of plastic and cheap electronics, but
that's the bike biz.

But why would they need a regulator at all? My point is, bike dynamos
are naturally constant current, and they put out pretty close to 0.5
Amp rms. That seems a useful value in the high powered LEDs I've seen
and used, with only rectification needed. So why regulate something
that's already constant?

Again, I'm not an EE, so please feel free to tell me what I'm missing.

- Frank Krygowski

I don't know, my guess is that they may regulate to match to a variety
of power sources, like different voltage generators, and/or batteries.
My point is that even full regulation at 3W is extremely cheap and
simple these days.

With the efficiency of modern LED's, it's easy to put out a lot of
light. With incandescent bulbs, the problem was to use a marginally
adequate amount of light optimally. The new lights are powerful enough
that the problem becomes one of not dazzling oncoming traffic. I think
these are different problems; while they both may involve some beam
shaping/shading, the latter design is much easier. You just have to
provide a vertical cutoff, side spill is advantageous and you have light
to spare.

As bike lights approach MV lights in intensity, the short wheelbase and
lack of suspension of bicycles can create problems for lights with even
a carefully shaped beam. I find it more natural to use a miner's style
light than an auto's.