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#21
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The last headlight you will ever need
Sir Ridesalot wrote:
Frank Krygowski wrote: Jeff Liebermann wrote: Also, I blundered into this article on using a bicycle to generate electricity. I haven't read it in detail, but basically the author suggests it's a lousy idea. http://www.lowtechmagazine.com/2011/05/bike-powered-electricity-generators.html It's certainly a lousy idea if the intent is to use electricity to drive devices that can reasonably be driven mechanically. Consider what it would take to generate and store electricity to run an electric can opener, vs. just cranking a manual can opener for 15 seconds. Many years ago, we were asked to donate appliances, etc. to an impoverished immigrant family that had moved to our area. Among our donations was a manual can opener. The woman accepting donations was astonished - "Do those things still work?" etc. She'd used only an electric one for years. But earlier still, when we were given an electric one as a gift, we returned it to the store. Bicycling for transportation does have very high efficiency, but that's the result of a different factor. When a person rides a bike, they're not hauling around 3000 pounds of metal, plastic, rubber and glass. The moving mass is almost all payload. Related: http://www.bicyclinglife.com/Effecti...cacy/bacon.htm In the rticle from the first link they talk about dead zones in the pedal cycle when using a bicycle to power a generator on a bicycle type trainer. I wonder if BioPace or other oval chainrings would help there? 'Dead zone' is a common comment when non-cyclists analyze cycling. In theory maybe, but in practice not so much. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
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#22
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The last headlight you will ever need
On Wednesday, March 26, 2014 1:37:46 PM UTC-4, AMuzi wrote:
Sir Ridesalot wrote: Frank Krygowski wrote: Jeff Liebermann wrote: Also, I blundered into this article on using a bicycle to generate electricity. I haven't read it in detail, but basically the author suggests it's a lousy idea. http://www.lowtechmagazine.com/2011/05/bike-powered-electricity-generators.html It's certainly a lousy idea if the intent is to use electricity to drive devices that can reasonably be driven mechanically. Consider what it would take to generate and store electricity to run an electric can opener, vs. just cranking a manual can opener for 15 seconds. Many years ago, we were asked to donate appliances, etc. to an impoverished immigrant family that had moved to our area. Among our donations was a manual can opener. The woman accepting donations was astonished - "Do those things still work?" etc. She'd used only an electric one for years. But earlier still, when we were given an electric one as a gift, we returned it to the store. Bicycling for transportation does have very high efficiency, but that's the result of a different factor. When a person rides a bike, they're not hauling around 3000 pounds of metal, plastic, rubber and glass. The moving mass is almost all payload. Related: http://www.bicyclinglife.com/Effecti...cacy/bacon.htm In the rticle from the first link they talk about dead zones in the pedal cycle when using a bicycle to power a generator on a bicycle type trainer. I wonder if BioPace or other oval chainrings would help there? 'Dead zone' is a common comment when non-cyclists analyze cycling. In theory maybe, but in practice not so much. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 Yes, many people including a lot of casual bicyclist think in terms of pistons rather than pedaling in circles. Cheers |
#23
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The last headlight you will ever need
On Wed, 26 Mar 2014 18:53:41 +1100, James
wrote: On 26/03/14 16:02, Jeff Liebermann wrote: http://www.myra-simon.com/bike/dynotest.html SP claims 72% for theirs. This claims 67% for a SON. http://www.ctc.org.uk/file/public/fe...ub-dynamos.pdf See the description of how the hubs were tested on Pg 61. "...electrical output is monitored with a 12 ohm resistance, since that’s how it’s always been done, as bulbs are also resistors." Ummm... bulbs are not constant resistance, which varies with applied voltage. Same with LED lamps that have built in current regulators. "...his apparatus mounts the hubshell in a lathe chuck and turns it at a set speed whilst measuring the drag force on a lever attached to the axle." It kinda looks like they measured the hub drag, and used that to calculate efficiency (and ignored maybe 0.05 watts of bearing drag). For example, the Son hub shows a difference in drag (with and without a load) of: 6.39 - 1.05 watts = 5.34 watts (at 30 km/hr) yet the graph shows that at 30 km/hr, it will only output 4.0 watts. If you believe those numbers, then the efficiency should be the power delivered divided by the drag under load or: 4.0 / 6.39 = 63% which is close enough to the claimed 67% for the SON that I would guess(tm) that's how it was done. I would feel better if they had measured the input torque with a force guage to get the input power, and used a load resembling a real LED light. I know I'm reading between the lines, but I'm somewhat suspicious since there are no details on the methods, no intermediate results, and no calculations used to obtain their results. Hmmm... I think I need to get some sleep. Yep, you do. Not a joke this time. I had 2 hrs sleep the night before and have been working continuously on a project that finally escaped my desk late last night. By the time I posted my messages, I was a zombie. I'm taking the day off today to recover. A large truck decided to roll over on the local highway this morning, so I have another excuse to not go to the office and do nothing today. Back to sleep, I guess. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#24
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The last headlight you will ever need
On Wed, 26 Mar 2014 11:28:00 -0400, Frank Krygowski
wrote: On 3/26/2014 1:02 AM, Jeff Liebermann wrote: Also, I blundered into this article on using a bicycle to generate electricity. I haven't read it in detail, but basically the author suggests it's a lousy idea. http://www.lowtechmagazine.com/2011/05/bike-powered-electricity-generators.html It's certainly a lousy idea if the intent is to use electricity to drive devices that can reasonably be driven mechanically. Ummm... I was talking about bicycle lamps. I suppose I could conjure a mechanically driven bicycle lamp, but electric power seems to be more convenient and practical. Ah, got it. Instead of a dynamo, I install a hollow steel flywheel. Around the outer edge, I attach an array of cigarette lighter flints. When turning, the flints will produce highly visible sparks. Add a reflector and I have a mechanical headlight that just might be more efficient than an electrically driven headlight. I'll leave the details, such as how to keep the sparks from setting my clothes on fire, to production engineering. Consider what it would take to generate and store electricity to run an electric can opener, vs. just cranking a manual can opener for 15 seconds. Hmmm... I haven't seen any bicycle powered can openers, but I suppose one could be designed. Speed reduction seems to be the major problem, so I would suggest an outboard worm gear, driving a sprocket, with the power transmitted to the can opener via a speedometer cable. I'm not sure there's a market, but if you label it "high efficiency" and "ecologically correct", it should bring in some sales. Many years ago, we were asked to donate appliances, etc. to an impoverished immigrant family that had moved to our area. Among our donations was a manual can opener. The woman accepting donations was astonished - "Do those things still work?" etc. She'd used only an electric one for years. But earlier still, when we were given an electric one as a gift, we returned it to the store. Chuckle. I still use a manual can opener. I tried an electric opener but found that it was slow and required disassembly for cleaning. When the stress of opening some bent rim cans (50% off at the local market) destroyed the plastic case, I gave up on it. Why anyone would want an electric can opener is beyond my limited imagination. Bicycling for transportation does have very high efficiency, but that's the result of a different factor. When a person rides a bike, they're not hauling around 3000 pounds of metal, plastic, rubber and glass. The moving mass is almost all payload. Related: http://www.bicyclinglife.com/Effecti...cacy/bacon.htm Nice story, but the answer is obvious. We are a nation of convenience addicts. It doesn't matter if it's economical, efficient, ecologically correct, or even in fashion. If it's not convenient, to won't sell. If you price modern convenience devices back to where the raw materials were excavated from the ground, literally everything that we do and buy can be done better, cheaper, and with less damage to the environment if done manually or mechanically. It's much like the old labor union joke, where the union guy complains that a steam shovel has replaced 100 men with hand shovels, and where the business owner retorts "why not 1000 men with teaspoons". It's difficult to roll back progress, especially when the automobile is considered an advancement over the bicycle. Anyway, hauling around 3000 lbs of automobile is not very efficient or economical, but it sure is convenient, especially if the bacon is far away. Ugh... topic drift... need sleep... -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#25
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The last headlight you will ever need
On 3/26/2014 12:29 PM, Jeff Liebermann wrote:
snip Hmmm... I haven't seen any bicycle powered can openers, but I suppose one could be designed. Speed reduction seems to be the major problem, so I would suggest an outboard worm gear, driving a sprocket, with the power transmitted to the can opener via a speedometer cable. I'm not sure there's a market, but if you label it "high efficiency" and "ecologically correct", it should bring in some sales. You need to work on a bicycle driven coffee grinder. For bicycle tourists without access to electric power the present options suck because the manual grinders are extremely slow. Contrary to what was shown in the movie City Slickers, there are no battery powered coffee grinders. The closest I've come is this: http://nordicgroup.us/bikecoff/bcimages/batterygrinder.JPG but this 12VDC grinder has been discontinued. |
#26
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The last headlight you will ever need
On 3/26/2014 4:22 PM, sms wrote:
On 3/26/2014 12:29 PM, Jeff Liebermann wrote: snip Hmmm... I haven't seen any bicycle powered can openers, but I suppose one could be designed. Speed reduction seems to be the major problem, so I would suggest an outboard worm gear, driving a sprocket, with the power transmitted to the can opener via a speedometer cable. I'm not sure there's a market, but if you label it "high efficiency" and "ecologically correct", it should bring in some sales. You need to work on a bicycle driven coffee grinder. For bicycle tourists without access to electric power the present options suck because the manual grinders are extremely slow. Contrary to what was shown in the movie City Slickers, there are no battery powered coffee grinders. The closest I've come is this: http://nordicgroup.us/bikecoff/bcimages/batterygrinder.JPG but this 12VDC grinder has been discontinued. There goes your commission! -- - Frank Krygowski |
#27
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The last headlight you will ever need
On Wed, 26 Mar 2014 11:28:00 -0400, Frank Krygowski
wrote: On 3/26/2014 1:02 AM, Jeff Liebermann wrote: Also, I blundered into this article on using a bicycle to generate electricity. I haven't read it in detail, but basically the author suggests it's a lousy idea. http://www.lowtechmagazine.com/2011/05/bike-powered-electricity-generators.html It's certainly a lousy idea if the intent is to use electricity to drive devices that can reasonably be driven mechanically. Consider what it would take to generate and store electricity to run an electric can opener, vs. just cranking a manual can opener for 15 seconds. Many years ago, we were asked to donate appliances, etc. to an impoverished immigrant family that had moved to our area. Among our donations was a manual can opener. The woman accepting donations was astonished - "Do those things still work?" etc. She'd used only an electric one for years. But earlier still, when we were given an electric one as a gift, we returned it to the store. Bicycling for transportation does have very high efficiency, but that's the result of a different factor. When a person rides a bike, they're not hauling around 3000 pounds of metal, plastic, rubber and glass. The moving mass is almost all payload. Related: http://www.bicyclinglife.com/Effecti...cacy/bacon.htm The Army had pedal generated generators in WW II. Supposed to provide emergency power for radios or some such use. The problem is that human power is not very effective. About the smallest auxiliary generator I see these days is a 600 watt unit, Little 2 stroke engine will put out a continuous 600 watts all day on a tank of gas :-) -- Cheers, John B. |
#28
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The last headlight you will ever need
On Wed, 26 Mar 2014 13:22:45 -0700, sms
wrote: On 3/26/2014 12:29 PM, Jeff Liebermann wrote: snip Hmmm... I haven't seen any bicycle powered can openers, but I suppose one could be designed. Speed reduction seems to be the major problem, so I would suggest an outboard worm gear, driving a sprocket, with the power transmitted to the can opener via a speedometer cable. I'm not sure there's a market, but if you label it "high efficiency" and "ecologically correct", it should bring in some sales. You need to work on a bicycle driven coffee grinder. For bicycle tourists without access to electric power the present options suck because the manual grinders are extremely slow. Contrary to what was shown in the movie City Slickers, there are no battery powered coffee grinders. The closest I've come is this: http://nordicgroup.us/bikecoff/bcimages/batterygrinder.JPG but this 12VDC grinder has been discontinued. My goodness but you Americans seem so inapt. One can easily pound coffee beans into a powder with a mortar and pestle. Just like the old folks used to. But of course, you probably can't figure out how to operate one of those. -- Cheers, John B. |
#29
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The last headlight you will ever need
On 3/26/2014 3:07 PM, Jeff Liebermann wrote:
On Wed, 26 Mar 2014 18:53:41 +1100, James wrote: On 26/03/14 16:02, Jeff Liebermann wrote: http://www.myra-simon.com/bike/dynotest.html SP claims 72% for theirs. This claims 67% for a SON. http://www.ctc.org.uk/file/public/fe...ub-dynamos.pdf See the description of how the hubs were tested on Pg 61. "...electrical output is monitored with a 12 ohm resistance, since that’s how it’s always been done, as bulbs are also resistors." Ummm... bulbs are not constant resistance, which varies with applied voltage. Same with LED lamps that have built in current regulators. I wondered about that when I read it. Personally, I think a fixed 12 Ohm resistor was a good enough load for comparing generators back in the days of halogen bulbs. But we are pretty thoroughly in the LED era. I just put one of my bikes on my workstand. It's got a Shimano hub dynamo (DH-3N30) and a Busch & Muller IQ Cyo LED headlamp. There's also a homebrew LED taillight. Anyway, I hooked up a voltmeter and spun the wheel at 9.5 mph (15.3 kph) and at 30 mph (48 kph), using an electric drill fitted with two different diameter sanding disks. At both those speeds, the voltage was only 3.9 Volts. That's significantly less than what would result with a 12 Ohm load. (Knowing the characteristics of dynamos, it's pretty certain the hub was still putting out half an amp, so that hub was putting out only about 2 Watts. ) That tells me that LED lights don't need to consume even 3 Watts. My riding experience tells me that, with decent optics, those 2 Watts give plenty of light for any reasonable riding. It also means that the drag would be even less than what they measured with the 12 Ohm load. -- - Frank Krygowski |
#30
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The last headlight you will ever need
Jeff Liebermann wrote:
:Chuckle. I still use a manual can opener. I tried an electric opener :but found that it was slow and required disassembly for cleaning. When :the stress of opening some bent rim cans (50% off at the local market) :destroyed the plastic case, I gave up on it. Why anyone would want an :electric can opener is beyond my limited imagination. Arthritis. -- sig 114 |
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