#301
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Better Braking?
On 2/18/2020 6:25 AM, Sepp Ruf wrote:
snip And don't forget wasteful springs moving in the generator mount because the wheel is not perfectly trued. But wait, that's still top secret, we at SpringShine Corp. (Shenzen, Denmark) will be exploiting this effect to introduce WheelPulseLED®, the next big crowdfunded "lossless" project in bicycle lighting. I think that as panel trucks knock down low hanging branches they should also be charging batteries that are embedded into the trees and that drive inductive chargers that cyclists can ride next to to charge their battery powered lights. Very similar to inductive charging being used for mobile phones. |
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#302
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Better Braking?
On Tuesday, February 18, 2020 at 9:32:31 AM UTC+1, John B. wrote:
Of course there is a power loss but it is not the friction between the generator roller and the tire wall. You're dumber, Slow Johnny, than you accuse Tom of being. And you're very persistently dumb, too. It must be habit forming, or in your genes. Wear this smart pointed cap and write one hundred times on the blackboard: ANY TIME ONE WHEEL DRIVES ANOTHER BY FRICTION BETWEEN THEM, POWER IS LOST Andre Jute We can only hope you didn't breed any road kill |
#303
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Better Braking?
On Tuesday, February 18, 2020 at 3:17:24 PM UTC, sms wrote:
On 2/18/2020 6:25 AM, Sepp Ruf wrote: snip And don't forget wasteful springs moving in the generator mount because the wheel is not perfectly trued. But wait, that's still top secret, we at SpringShine Corp. (Shenzen, Denmark) will be exploiting this effect to introduce WheelPulseLED®, the next big crowdfunded "lossless" project in bicycle lighting. I think that as panel trucks knock down low hanging branches they should also be charging batteries that are embedded into the trees and that drive inductive chargers that cyclists can ride next to to charge their battery powered lights. Very similar to inductive charging being used for mobile phones. Where I live, even the bigger SUVs can knock down branches, as can cyclists who sit upright on properly-sized bikes. I'll tell you something else: before Kreepy Krygo even starts screeching that he knows better than the people who live here how low the branches sweep over the road, the Council and the environmentalists make matters worse. The Council has a regulation, made under the influence of the Greenies, that the hedges should not be cut before September 30th, and to avoid trouble is inclined to view trees beside the road as "hedge". And the environmentalists, if they see a mobile hedge trimmer or Council tree surgeon truck in the lanes before the end of October, are instantly on the phone to the Council and their Member of Parliament to complain to high heaven that the Council is ruining the countryside -- again. Andre Jute Who would be foolish enough to run for election to any post where the environmentalists can complain about what he does or doesn't do? |
#304
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Better Braking?
John B. wrote:
On Tue, 18 Feb 2020 04:48:17 +0000 (UTC), Ralph Barone wrote: John B. wrote: On Mon, 17 Feb 2020 06:17:01 -0800 (PST), Tom Kunich wrote: On Saturday, February 15, 2020 at 6:50:46 AM UTC-8, AMuzi wrote: On 2/14/2020 10:18 PM, Frank Krygowski wrote: On Friday, February 14, 2020 at 6:34:47 PM UTC-5, AMuzi wrote: On 2/14/2020 5:05 PM, Frank Krygowski wrote: On 2/14/2020 5:47 PM, John B. wrote: On Fri, 14 Feb 2020 21:35:18 -0000 (UTC), Duane wrote: jbeattie wrote: On Friday, February 14, 2020 at 11:35:46 AM UTC-8, Duane wrote: On 2/14/2020 2:23 PM, Sir Ridesalot wrote: On Friday, 14 February 2020 12:00:11 UTC-5, Frank Krygowski wrote: On 2/13/2020 5:47 PM, Tom Kunich wrote: On Thursday, February 13, 2020 at 2:36:58 PM UTC-8, John B. Slocomb wrote: Own Data? You mean like your assertions that a cheap Chinese flashlight is a perfect bicycle head light? ... I have taken Steven's word at the effectiveness of "cheap Chinese flashlights as bicycle lights" and he was completely correct. Sorry if you seem to think that you know anything about anything but you have shown yourself to be a great deal heavier on opinion than knowledge of anything. You say Mr. Scharf was completely correct when he touted cheap Chinese flashlights as bike headlights. That was when he said dyno powered headlights were terrible and foolish. Problem is, Mr. Scharf is now using dyno powered headlights on his bikes, and no longer seems to say cheap Chinese flashlights are perfect. My first question is, was he completely correct back then? Or is he completely correct now? My second question regards specific details. My dyno powered LED headlights illuminate the entire width of the lane, and simultaneously illuminate stop signs up to a quarter mile away from me, all without blinding oncoming riders. The Chinese flashlight I tried could not do that, no matter how I adjusted the tilt and the focus. It was a truly crappy headlight. What, specifically, does yours do? What's its brand and model? -- - Frank Krygowski Some people use flashlights that have a narrow beam but good range. Those lights might be okay as a be seen light but they don't light up much of the road. Others use flashlights with adjustable focus that spread the beams to light of more of the road. the trouble is that when they do that they lose the range they need if riding in totally dark conditions with no city lights. I really like my CygoLite Rover II light as it does light up the two lanes of the country roads around here and it does so no matter what speed I'm riding at. Also, I can move the battery and light unit from bike to bike easily. I do wish it had a bit more range. For that reason I was considering getting the Centauri or Trident. Dynamo lights simply don't meet my needs. Cheers I imagine it depends on what you want. I use a Planet Bike 2w when I'm doing club rides in the evening because it's dark on my ride back home from the start. But I'm not out in the country, only the burbs. I don't need a lot of distance but I need something to show me the potholes in enough time to avoid them. My guess is that a flashlight would probably work in that case. Then you have people riding in the rain, pitch dark, pitch dark rain down steep declines etc. etc. etc. I seriously doubt that there's a one for all solution. In the latter circumstances, a dyno clearly is not the solution. In stormy weather, fast downhill or trail, a bright battery light is best . . . for me, and speaking as someone who owns a dyno and battery lights. I can A/B my dyno and my little all-in-on L&M Urban 800 every night since I use both. The L&M produces far better light; it is one fourth the total price of my dyno set up and suffers only in that it requires charging. -- Jay Beattie. Like I’ve said before most of times that I’m riding at night it’s by accident. The few planned times are as I described. So a dyno doesn’t do much for me. Oddly, "riding at night by accident" is one of the main reasons I settled on dyno lights. A big event for me was being on a solo tour in Middle-Of-Nowhere Township, trying to get to a particular state park. It was hillier than I anticipated, dinner in a restaurant took extra long, and surprise, I had to do the last few miles in the dark. So I pulled out the battery light I'd brought and turned it on. The batteries got me to, oh, 3 to 5 miles from the campground. Then nothing. On a two lane country highway. Fortunately, traffic was light. I finished by pulling way off the side of the road whenever a car came. I then installed a dyno on every bike. Since then, there have been countless times I didn't plan on riding in the dark, but had to - meetings that ran long, extra work to get done, having too much fun to leave, etc. It's no problem. My lights are just like those on my car. No preparation needed, just turn them on and they work. I can see that wouldn't be valuable for people who use their bikes differently than I do. As for charging, it’s pretty much routine. I have to charge my phone, my Garmin, my lights and even my watch. Pfft. Battery charge is now an issue. A Garmin and a phone that can last for a 175km ride hS become a thing. Again, we all have different requirements. The fact that we all ride bikes is way cool. Too bad we can’t avoid the bull**** here. and then a thread would look like: Hey! I use a Gamnin! ----- You do? So do I. ---- Wow! I use one too. --- Doesn't everybody use a Garmin? --- So cheap they ought to. --- :-) :-) And it would require so little technical thinking! Win - win! Well, someone could always very precisely measure some aspect another guy cares nothing about and call it 'data'. I don't think it's better to give no measurements, nothing but a vague "mine is better" opinion, and say "data doesn't matter." What do you use for lights? How well do they work for you? Why? - Frank Krygowski Exactly. You and I have chosen no-switch always-on dynamos with which we are satisfied based on convenience and dependability with virtually zero maintenance. Heated discussions of amp hours, megalumens and optic patterns may be vaguely interesting but not relevant to my (our?) cycling. Regarding the topic, braking, ditto. No one disputes that big fluid discs have better peak braking power and heat dissipation for sustained braking power. One might chart those factors impressively in comparison to rim brakes. For the bike I ride this time of year, a simple sidepull front with fixed gear is perfectly adequate and I've never wanted for more braking power[1] on that bike given the way I use it. I'm not Jay, nor Joerg, who have different needs and taste. [1] what that bike really needs is a heater! -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I am quite aware that friction losses from a hub generator are minor but that isn't so for a sidewall generator because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output. Er... Tommy, frictional losses in mechanical devices is: " Friction occurs when two bodies are in contact with each other and have relative motion". However you say " pressed very tightly against the sidewall to keep it was slipping" and if there is no slipping than obviously there is no relative motion and thus no friction. Call it frictional losses or rolling resistance, but power is lost rolling a bottle generator against a sidewall beyond that which a hub generator would incur. Of course there is a power loss but it is not the friction between the generator roller and the tire wall. No, but unless you are making a point of being pedantic (which seems to happen a lot around here), you could say that the hysteresis losses in the tire sidewalk that occur when it is deformed and then released are due to friction like effects within the bulk of the rubber. AND ONCE AGAIN THE INDOMONIBLE TOMMIE PROVES TO THE WORLD that he doesn't know what he is talking about. When Frank is telling us that he only lost on mph at a speed where he is generating almost his entire output capacity my eyes are rolling and so must everyone's. No Tommy, the eyes are rolling because you don't know what you are talking about. -- cheers, John B. -- cheers, John B. |
#305
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Better Braking?
On 2/18/2020 11:08 AM, Ralph Barone wrote:
John B. wrote: On Tue, 18 Feb 2020 04:48:17 +0000 (UTC), Ralph Barone wrote: John B. wrote: However you say " pressed very tightly against the sidewall to keep it was slipping" and if there is no slipping than obviously there is no relative motion and thus no friction. Call it frictional losses or rolling resistance, but power is lost rolling a bottle generator against a sidewall beyond that which a hub generator would incur. Of course there is a power loss but it is not the friction between the generator roller and the tire wall. No, but unless you are making a point of being pedantic (which seems to happen a lot around here), you could say that the hysteresis losses in the tire sidewalk that occur when it is deformed and then released are due to friction like effects within the bulk of the rubber. It does get a bit complicated. With a sidewall dynamo, the contact patch between the dyno and the tire is fairly rectangular. (You can check that using carbon paper, if you can still find some.) The tire's surface velocity at the largest radius of that rectangle is greater than at the smallest radius of that rectangle. If the roller is cylindrical (as on old Union dynos), there has to be some scrubbing. (I have one obscure Japanese dyno with a somewhat conical roller, and I wonder if that's the reason for its shape.) As I've said before, on a couple bikes I've lathe-turned an O-ring groove into the dyno roller and I run the O-ring on the braking surface of the rim. This should minimize that source of friction, but I can't say how much. It certainly makes the dyno quieter. But the dyno I used in the event I described was a bottom bracket or roller design, installed behind the crankset. The roller is larger than that of a bottle dyno, so it sees less force; and it rotates in the same plane as the tire. I've measured higher efficiency for those, compared to bottle dynos. So have others in their lab tests. But any time a rubber surface is used to drive rotation, some friction loss must occur because of flexibility of the rubber, hysteresis losses, and velocity differences like those above. Similarly, your bike's wheel rotation speed is not computed precisely by V=r*omega. There's always microscopic "slippage" due to the tire flexing. Tires also flex laterally when asked to steer, so your front wheel doesn't go precisely where it's pointed in a curve. This is true for cars as well as bikes. There's no doubt a hub dyno has less loss than both the above designs. I've got them on a couple of bikes, and will probably get more. -- - Frank Krygowski |
#306
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Better Braking?
On Tue, 18 Feb 2020 16:08:29 +0000 (UTC), Ralph Barone
wrote: John B. wrote: On Tue, 18 Feb 2020 04:48:17 +0000 (UTC), Ralph Barone wrote: John B. wrote: On Mon, 17 Feb 2020 06:17:01 -0800 (PST), Tom Kunich wrote: On Saturday, February 15, 2020 at 6:50:46 AM UTC-8, AMuzi wrote: On 2/14/2020 10:18 PM, Frank Krygowski wrote: On Friday, February 14, 2020 at 6:34:47 PM UTC-5, AMuzi wrote: On 2/14/2020 5:05 PM, Frank Krygowski wrote: On 2/14/2020 5:47 PM, John B. wrote: On Fri, 14 Feb 2020 21:35:18 -0000 (UTC), Duane wrote: jbeattie wrote: On Friday, February 14, 2020 at 11:35:46 AM UTC-8, Duane wrote: On 2/14/2020 2:23 PM, Sir Ridesalot wrote: On Friday, 14 February 2020 12:00:11 UTC-5, Frank Krygowski wrote: On 2/13/2020 5:47 PM, Tom Kunich wrote: On Thursday, February 13, 2020 at 2:36:58 PM UTC-8, John B. Slocomb wrote: Own Data? You mean like your assertions that a cheap Chinese flashlight is a perfect bicycle head light? ... I have taken Steven's word at the effectiveness of "cheap Chinese flashlights as bicycle lights" and he was completely correct. Sorry if you seem to think that you know anything about anything but you have shown yourself to be a great deal heavier on opinion than knowledge of anything. You say Mr. Scharf was completely correct when he touted cheap Chinese flashlights as bike headlights. That was when he said dyno powered headlights were terrible and foolish. Problem is, Mr. Scharf is now using dyno powered headlights on his bikes, and no longer seems to say cheap Chinese flashlights are perfect. My first question is, was he completely correct back then? Or is he completely correct now? My second question regards specific details. My dyno powered LED headlights illuminate the entire width of the lane, and simultaneously illuminate stop signs up to a quarter mile away from me, all without blinding oncoming riders. The Chinese flashlight I tried could not do that, no matter how I adjusted the tilt and the focus. It was a truly crappy headlight. What, specifically, does yours do? What's its brand and model? -- - Frank Krygowski Some people use flashlights that have a narrow beam but good range. Those lights might be okay as a be seen light but they don't light up much of the road. Others use flashlights with adjustable focus that spread the beams to light of more of the road. the trouble is that when they do that they lose the range they need if riding in totally dark conditions with no city lights. I really like my CygoLite Rover II light as it does light up the two lanes of the country roads around here and it does so no matter what speed I'm riding at. Also, I can move the battery and light unit from bike to bike easily. I do wish it had a bit more range. For that reason I was considering getting the Centauri or Trident. Dynamo lights simply don't meet my needs. Cheers I imagine it depends on what you want. I use a Planet Bike 2w when I'm doing club rides in the evening because it's dark on my ride back home from the start. But I'm not out in the country, only the burbs. I don't need a lot of distance but I need something to show me the potholes in enough time to avoid them. My guess is that a flashlight would probably work in that case. Then you have people riding in the rain, pitch dark, pitch dark rain down steep declines etc. etc. etc. I seriously doubt that there's a one for all solution. In the latter circumstances, a dyno clearly is not the solution. In stormy weather, fast downhill or trail, a bright battery light is best . . . for me, and speaking as someone who owns a dyno and battery lights. I can A/B my dyno and my little all-in-on L&M Urban 800 every night since I use both. The L&M produces far better light; it is one fourth the total price of my dyno set up and suffers only in that it requires charging. -- Jay Beattie. Like I’ve said before most of times that I’m riding at night it’s by accident. The few planned times are as I described. So a dyno doesn’t do much for me. Oddly, "riding at night by accident" is one of the main reasons I settled on dyno lights. A big event for me was being on a solo tour in Middle-Of-Nowhere Township, trying to get to a particular state park. It was hillier than I anticipated, dinner in a restaurant took extra long, and surprise, I had to do the last few miles in the dark. So I pulled out the battery light I'd brought and turned it on. The batteries got me to, oh, 3 to 5 miles from the campground. Then nothing. On a two lane country highway. Fortunately, traffic was light. I finished by pulling way off the side of the road whenever a car came. I then installed a dyno on every bike. Since then, there have been countless times I didn't plan on riding in the dark, but had to - meetings that ran long, extra work to get done, having too much fun to leave, etc. It's no problem. My lights are just like those on my car. No preparation needed, just turn them on and they work. I can see that wouldn't be valuable for people who use their bikes differently than I do. As for charging, it’s pretty much routine. I have to charge my phone, my Garmin, my lights and even my watch. Pfft. Battery charge is now an issue. A Garmin and a phone that can last for a 175km ride hS become a thing. Again, we all have different requirements. The fact that we all ride bikes is way cool. Too bad we can’t avoid the bull**** here. and then a thread would look like: Hey! I use a Gamnin! ----- You do? So do I. ---- Wow! I use one too. --- Doesn't everybody use a Garmin? --- So cheap they ought to. --- :-) :-) And it would require so little technical thinking! Win - win! Well, someone could always very precisely measure some aspect another guy cares nothing about and call it 'data'. I don't think it's better to give no measurements, nothing but a vague "mine is better" opinion, and say "data doesn't matter." What do you use for lights? How well do they work for you? Why? - Frank Krygowski Exactly. You and I have chosen no-switch always-on dynamos with which we are satisfied based on convenience and dependability with virtually zero maintenance. Heated discussions of amp hours, megalumens and optic patterns may be vaguely interesting but not relevant to my (our?) cycling. Regarding the topic, braking, ditto. No one disputes that big fluid discs have better peak braking power and heat dissipation for sustained braking power. One might chart those factors impressively in comparison to rim brakes. For the bike I ride this time of year, a simple sidepull front with fixed gear is perfectly adequate and I've never wanted for more braking power[1] on that bike given the way I use it. I'm not Jay, nor Joerg, who have different needs and taste. [1] what that bike really needs is a heater! -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I am quite aware that friction losses from a hub generator are minor but that isn't so for a sidewall generator because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output. Er... Tommy, frictional losses in mechanical devices is: " Friction occurs when two bodies are in contact with each other and have relative motion". However you say " pressed very tightly against the sidewall to keep it was slipping" and if there is no slipping than obviously there is no relative motion and thus no friction. Call it frictional losses or rolling resistance, but power is lost rolling a bottle generator against a sidewall beyond that which a hub generator would incur. Of course there is a power loss but it is not the friction between the generator roller and the tire wall. No, but unless you are making a point of being pedantic (which seems to happen a lot around here), you could say that the hysteresis losses in the tire sidewalk that occur when it is deformed and then released are due to friction like effects within the bulk of the rubber. I was replying to Tom who said, "because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output." That simply isn't true. AND ONCE AGAIN THE INDOMONIBLE TOMMIE PROVES TO THE WORLD that he doesn't know what he is talking about. When Frank is telling us that he only lost on mph at a speed where he is generating almost his entire output capacity my eyes are rolling and so must everyone's. No Tommy, the eyes are rolling because you don't know what you are talking about. -- cheers, John B. -- cheers, John B. -- cheers, John B. |
#307
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Better Braking?
Am 18.02.2020 um 23:53 schrieb John B.:
I was replying to Tom who said, "because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output." That simply isn't true. The order of magnitude is true; sidewall dynamos typically have 10W braking power for 3W electrical power. I believe the Sanyo Roller Dynamo had on the order of 6-7W braking poer for 3W electrical power, (a hub dynamo is on the order of 3W for 3W). |
#308
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Better Braking?
On Monday, February 17, 2020 at 8:48:19 PM UTC-8, Ralph Barone wrote:
On Mon, 17 Feb 2020 06:17:01 -0800 (PST), Tom Kunich wrote: I am quite aware that friction losses from a hub generator are minor but that isn't so for a sidewall generator because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output. Er... Tommy, frictional losses in mechanical devices is: " Friction occurs when two bodies are in contact with each other and have relative motion". However you say " pressed very ti... You seem to have a misunderstanding of frictional losses. The sidewall generator doesn't move relative to the tire but the tire and innertube are displaced because of the pressure of the generator to keep from slipping. There is relative motion but not any sort of slipping or rubbing. You can also get frictional losses electro-magnetically such as in a hub generator where the magnetic field resists the coils moving through them and turning motion through the field into electrical power. |
#309
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Better Braking?
On Tuesday, February 18, 2020 at 2:21:40 AM UTC-8, wrote:
On Tuesday, February 18, 2020 at 9:32:31 AM UTC+1, John B. wrote: Of course there is a power loss but it is not the friction between the generator roller and the tire wall. Of course there is friction between the generator roller and the tire because the direction of the circumferential speed of the roller is not exactly aligned with that of the tire. Lou I suppose you're correct since you are on a tire that has a changing diameter while the roller on the generator has a fixed diameter. But I always had the idea that the real losses were from the displacement of the sidewall. |
#310
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Better Braking?
On Wednesday, February 19, 2020 at 12:45:14 AM UTC-8, Rolf Mantel wrote:
Am 18.02.2020 um 23:53 schrieb John B.: I was replying to Tom who said, "because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output." That simply isn't true. The order of magnitude is true; sidewall dynamos typically have 10W braking power for 3W electrical power. I believe the Sanyo Roller Dynamo had on the order of 6-7W braking poer for 3W electrical power, (a hub dynamo is on the order of 3W for 3W). Lordy how I hate to say it but Frank had a moment of lucidity and pretty well described the problems with sidewall generators. Though I still believe that the majority of losses are from the deformation of he tire and innertube. If you must have nighttime lighting, you there is simply no competition to a hub generator. Though they are a pain in the butt and usually are only useful on cargo-type bicycles. |
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