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Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge.
This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator. But that's a little hard to tell since they seem to have a great deal of trouble listing the output of the various dynamos. You can get a 6 watt bulb generator but the hubs appear to all deliver 3 watts. Now there are extremely efficient hubs that even Frank wouldn't have any trouble peddling in his old broken down and crippled state. But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out. There are a few things that I really like the idea of in a commuter bike: A front wheel hub generator - the German Schmidt which is extremely reliable and apparently is 78% efficient so Jorge could not complain that he is having trouble pedalling against the tide. The Shimano Alfine is an 11-speed rear hub which has the decided advantage of being able to put a total cover chain guard around the entire chain and SINGLE SPEED front ring and still be able to leap tall buildings in a single bound. Now building this set of wheel would cost the better part of a thousand dollars and we're all a bunch of cheapskates. But with bikes costing $5K+ I'm sure you could build the perfect commuter for half that amount. |
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On Sunday, March 5, 2017 at 1:56:13 PM UTC-5, wrote:
Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge. This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator. But that's a little hard to tell since they seem to have a great deal of trouble listing the output of the various dynamos. You can get a 6 watt bulb generator but the hubs appear to all deliver 3 watts. Now there are extremely efficient hubs that even Frank wouldn't have any trouble peddling in his old broken down and crippled state. But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out. There are a few things that I really like the idea of in a commuter bike: A front wheel hub generator - the German Schmidt which is extremely reliable and apparently is 78% efficient so Jorge could not complain that he is having trouble pedalling against the tide. The Shimano Alfine is an 11-speed rear hub which has the decided advantage of being able to put a total cover chain guard around the entire chain and SINGLE SPEED front ring and still be able to leap tall buildings in a single bound. Now building this set of wheel would cost the better part of a thousand dollars and we're all a bunch of cheapskates. But with bikes costing $5K+ I'm sure you could build the perfect commuter for half that amount. Once again; *SOME PEOPLE PREFER THE CONVENIENCE OF BATTERY LIGHTS FOR THEIR OWN USES!* If I had to spend $2,500.00 for a commuter bicycle I'd seriously look at a used car just for commuting. Cheers |
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On Sunday, March 5, 2017 at 11:12:01 AM UTC-8, Sir Ridesalot wrote:
On Sunday, March 5, 2017 at 1:56:13 PM UTC-5, wrote: Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge. This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator. But that's a little hard to tell since they seem to have a great deal of trouble listing the output of the various dynamos. You can get a 6 watt bulb generator but the hubs appear to all deliver 3 watts. Now there are extremely efficient hubs that even Frank wouldn't have any trouble peddling in his old broken down and crippled state. But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out. There are a few things that I really like the idea of in a commuter bike: A front wheel hub generator - the German Schmidt which is extremely reliable and apparently is 78% efficient so Jorge could not complain that he is having trouble pedalling against the tide. The Shimano Alfine is an 11-speed rear hub which has the decided advantage of being able to put a total cover chain guard around the entire chain and SINGLE SPEED front ring and still be able to leap tall buildings in a single bound. Now building this set of wheel would cost the better part of a thousand dollars and we're all a bunch of cheapskates. But with bikes costing $5K+ I'm sure you could build the perfect commuter for half that amount. Once again; *SOME PEOPLE PREFER THE CONVENIENCE OF BATTERY LIGHTS FOR THEIR OWN USES!* If I had to spend $2,500.00 for a commuter bicycle I'd seriously look at a used car just for commuting. Cheers I don't recall forcing anything on you. Or do you simply object to opinions? |
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On Sunday, March 5, 2017 at 2:26:07 PM UTC-5, wrote:
On Sunday, March 5, 2017 at 11:12:01 AM UTC-8, Sir Ridesalot wrote: On Sunday, March 5, 2017 at 1:56:13 PM UTC-5, wrote: Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge. This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator. But that's a little hard to tell since they seem to have a great deal of trouble listing the output of the various dynamos. You can get a 6 watt bulb generator but the hubs appear to all deliver 3 watts. Now there are extremely efficient hubs that even Frank wouldn't have any trouble peddling in his old broken down and crippled state. But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out. There are a few things that I really like the idea of in a commuter bike: A front wheel hub generator - the German Schmidt which is extremely reliable and apparently is 78% efficient so Jorge could not complain that he is having trouble pedalling against the tide. The Shimano Alfine is an 11-speed rear hub which has the decided advantage of being able to put a total cover chain guard around the entire chain and SINGLE SPEED front ring and still be able to leap tall buildings in a single bound. Now building this set of wheel would cost the better part of a thousand dollars and we're all a bunch of cheapskates. But with bikes costing $5K+ I'm sure you could build the perfect commuter for half that amount. Once again; *SOME PEOPLE PREFER THE CONVENIENCE OF BATTERY LIGHTS FOR THEIR OWN USES!* If I had to spend $2,500.00 for a commuter bicycle I'd seriously look at a used car just for commuting. Cheers I don't recall forcing anything on you. Or do you simply object to opinions? BUT you did NOT express an opinion. You said: On Sunday, March 5, 2017 at 1:56:13 PM UTC-5, wrote: Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge. This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator." You intaht case is not myself nor is it a lot of other people who prefer battery powered lights for whatever reasons thosepeople have. Cheers |
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On Sunday, March 5, 2017 at 10:56:13 AM UTC-8, wrote:
Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge. This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator. But that's a little hard to tell since they seem to have a great deal of trouble listing the output of the various dynamos. You can get a 6 watt bulb generator but the hubs appear to all deliver 3 watts. Now there are extremely efficient hubs that even Frank wouldn't have any trouble peddling in his old broken down and crippled state. But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out. There are a few things that I really like the idea of in a commuter bike: A front wheel hub generator - the German Schmidt which is extremely reliable and apparently is 78% efficient so Jorge could not complain that he is having trouble pedalling against the tide. The Shimano Alfine is an 11-speed rear hub which has the decided advantage of being able to put a total cover chain guard around the entire chain and SINGLE SPEED front ring and still be able to leap tall buildings in a single bound. Now building this set of wheel would cost the better part of a thousand dollars and we're all a bunch of cheapskates. But with bikes costing $5K+ I'm sure you could build the perfect commuter for half that amount. Several items: Scale heat by 1:1, because a light along with the driver circuit is not a theoretically perfect system. My package's heatsink can cool 20 watts of heat to stay under 65C on the hottest outside point for seven minutes, at 72F/ 21C. It stays under ~50C with only a 6mph/10kph airflow. Patent number:8662697. Burn time: What if you had five or ten hours battery time at your generator's brightness? My Oculus gives at least that much brightness, and a quickly field replaceable battery so you can put in a fresh battery. Other rechargeables leave you out of light and out of luck when the battery drains. Oculus also comes with a spare battery included. Lumens per dollar: 1800/150 = 12. Lumens per gram: 1800/205 (with 18650, bracket and strap included) = 8.8 Diffusers and arrays generate huge amounts of glare vs the usable visibility that they create in the primary field of view that the eyes pay attention to. Btw MTBR is pay for play. Discreetly, obscurely, but pay for play for sure.. They also take deliberately altered pictures. See: https://drive.google.com/drive/folde...2c?usp=sharing These are pics that Francis posted on his personal Facebook with a defaming title and captions. Note the overexposure/underexposure of the far horizon blue tine, and white light dots in the distance. Also the biased center weighted versus full field light metering. He pulled the pics and posting, but refuses to test my lights or make any mention of them on his websites. I'll put my Oculus 1800 against ANYTHING he thinks is the best of anything. Side by side with the L&M Taz, along with the head of L&M, we see my light and the his light as neither absolute superiority in terms of the raw beam the lights put out. Roadies mostly prefer my beam over the Taz right away, some MTB riders like the Taz' beam. Honest side by side beam pictures on trails and roads will show that, not the skewed crap in favor of a big MTBR support that Francis posted. |
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On Sunday, March 5, 2017 at 11:32:51 AM UTC-8, Jeff Liebermann wrote:
On Sun, 5 Mar 2017 10:56:09 -0800 (PST), wrote: But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out. Hint: Measuring lumens is messy and expensive. Here's what it took to verify lumens in 2014: http://www.roadbikereview.com/reviews/2014-bike-lights-shootout-lumen-measurements (I like the lumens/dollar bar graph). For numbers and beam pattern photos, try: https://www.bikelightdatabase.com http://reviews.mtbr.com/2016-bike-lights-shootout-lumen-measurements http://reviews.mtbr.com/2016-bike-lights-shootout-beam-patterns http://road.cc/content/buyers-guide/212914-updated-your-guide-best-front-lights-cycling-beam-comparison-engine http://www.roadbikereview.com/reviews/2014-bike-lights-shootout-tunnel-beam-patterns There are others, but that's what I found in my bookmark collection. There are also comparisons and tests on YouTube. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 Thanks Jeff. These however all appear to be battery powered lights. We were sort of looking for lights that operated on the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or four times the power. This is why the hub generator has so little drag. |
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On Sunday, March 5, 2017 at 1:34:33 PM UTC-8, Sir Ridesalot wrote:
On Sunday, March 5, 2017 at 2:26:07 PM UTC-5, wrote: On Sunday, March 5, 2017 at 11:12:01 AM UTC-8, Sir Ridesalot wrote: On Sunday, March 5, 2017 at 1:56:13 PM UTC-5, wrote: Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge. This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator. But that's a little hard to tell since they seem to have a great deal of trouble listing the output of the various dynamos. You can get a 6 watt bulb generator but the hubs appear to all deliver 3 watts. Now there are extremely efficient hubs that even Frank wouldn't have any trouble peddling in his old broken down and crippled state. But when you look up the lights you find the same problem - you have a very difficult time finding power in and lumens out. There are a few things that I really like the idea of in a commuter bike: A front wheel hub generator - the German Schmidt which is extremely reliable and apparently is 78% efficient so Jorge could not complain that he is having trouble pedalling against the tide. The Shimano Alfine is an 11-speed rear hub which has the decided advantage of being able to put a total cover chain guard around the entire chain and SINGLE SPEED front ring and still be able to leap tall buildings in a single bound. Now building this set of wheel would cost the better part of a thousand dollars and we're all a bunch of cheapskates. But with bikes costing $5K+ I'm sure you could build the perfect commuter for half that amount. Once again; *SOME PEOPLE PREFER THE CONVENIENCE OF BATTERY LIGHTS FOR THEIR OWN USES!* If I had to spend $2,500.00 for a commuter bicycle I'd seriously look at a used car just for commuting. Cheers I don't recall forcing anything on you. Or do you simply object to opinions? BUT you did NOT express an opinion. You said: On Sunday, March 5, 2017 at 1:56:13 PM UTC-5, wrote: Since you people have been talking about lights I've been looking. Like sms I really don't like the idea of having normal batteries that wear out quickly or the idea of always keeping your battery on charge. This means you need a bulb generator or a hub generator. The hub generator seems a good answer but they don't appear to make half of the power of a bulb generator." You intaht case is not myself nor is it a lot of other people who prefer battery powered lights for whatever reasons thosepeople have. Cheers Well, I didn't realize that English isn't your first language. So rather than me changing my comments I suggest that you learn English. |
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On Sun, 5 Mar 2017 16:03:30 -0800 (PST), wrote:
Thanks Jeff. These however all appear to be battery powered lights. We were sort of looking for lights that operated on the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or four times the power. Sorry, I thought you were still open to looking at battery powered lights. Here's what I fished out of my bookmark dumpster. No reviews and few tests, but some interesting dynamo graphs and numbers: http://www.myra-simon.com/bike/dynotest.html http://pilom.com/BicycleElectronics/DynamoCircuits.htm http://www.eeweb.com/blog/extreme_circuits/power-mosfet-bridge-rectifier This one is well worth reading (or skimming) and has quite a few test results: http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html This is why the hub generator has so little drag. Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. You might find it useful to know how bright you want your light. For that, you'll need a Lux meter. I have a Lutron LX-102 which works nicely, and two junk meters I bought on eBay for sanity checks: http://www.ebay.com/sch/i.html?_nkw=lux+meter Get one that has a wide range. Lowest on mine is 1000 lux, and highest range is 50,000 lux. Find a dark night and an accomplice to operate the meter and send them down the road to the farthest distance that you might want to illuminate with your headlight. Use a headlight or flashlight to light up that area. Have your accompli's take a reading. It will probably be zero. Now, cut the distance in half and take a measurement. It will be 2x as bright (lux) at half the distance or 4x as bright at 1/4th the distance. Adjust the brightness for what it would have been if the light meter was sufficiently sensitive. Converting the brightness (lux) to luminous flux (lumens) requires that you know the distance to the accomplice, and the illumination angle. (1 lux = 1 lumen/square-meter) The form below makes a mess of bad assumptions but is good enough for a rough approximation: https://www.ledrise.com/shop_content.php?coID=19 Once you know how many lumens you think you need, and have adjusted for overly ambitious expectations, you can determine which lighting technology is suitable. Lets say you want to see 8 meters ahead and 20 degrees to each side (or 40 degree conical beamwidth) at 20 lux, which is rather dim. Plugging into the web page above, I get 485 lumens needed. You won't be able to do that with a 3w dynamo, but might squeeze by with a 6w and an oval shaped beam. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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On Sun, 05 Mar 2017 17:26:21 -0800, Jeff Liebermann
wrote: Find a dark night and an accomplice to operate the meter and send them down the road to the farthest distance that you might want to illuminate with your headlight. Use a headlight or flashlight to light up that area. Have your accompli's take a reading. It will probably be zero. Now, cut the distance in half and take a measurement. It will be 2x as bright (lux) at half the distance or 4x as bright at 1/4th the distance. Adjust the brightness for what it would have been if the light meter was sufficiently sensitive. No brain today. That should be half the distance equals 4 times as bright and 1/4th the distance equals 16 times as bright. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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On 06/03/17 10:22, Barry Beams wrote:
Burn time: What if you had five or ten hours battery time at your generator's brightness? My Oculus gives at least that much brightness, and a quickly field replaceable battery so you can put in a fresh battery. Other rechargeables leave you out of light and out of luck when the battery drains. Oculus also comes with a spare battery included. What if I don't want to play with batteries? -- JS |
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On 06/03/17 12:26, Jeff Liebermann wrote:
Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. We know that a 3W dynamo is quite capable of delivering more power than 3W, once the bicycle speed increases. 6W from a 3W dynamo is quite achievable, and the retardation torque drops off as speed increases too. -- JS |
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Assumptions or measured ?
|
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On Mon, 6 Mar 2017 17:04:13 +1100, James
wrote: On 06/03/17 12:26, Jeff Liebermann wrote: Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. We know that a 3W dynamo is quite capable of delivering more power than 3W, once the bicycle speed increases. 6W from a 3W dynamo is quite achievable, and the retardation torque drops off as speed increases too. Maybe: http://www.myra-simon.com/bike/dynotest.html See "Electrical Output" graph. Kinda looks like all of them will sorta deliver 2.5 watts before the core saturates (to provide some level of voltage regulation). Further down the page is a "Low Speed Power" graph, which shows that most can produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo will deliver 4.0 watts, but that would require buying one of the few better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph). If I were designing or sizing a lighting system suitable for my slow style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0 watt figures. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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On 3/6/2017 11:22 AM, Jeff Liebermann wrote:
On Mon, 6 Mar 2017 17:04:13 +1100, James wrote: On 06/03/17 12:26, Jeff Liebermann wrote: Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. We know that a 3W dynamo is quite capable of delivering more power than 3W, once the bicycle speed increases. 6W from a 3W dynamo is quite achievable, and the retardation torque drops off as speed increases too. Maybe: http://www.myra-simon.com/bike/dynotest.html See "Electrical Output" graph. Kinda looks like all of them will sorta deliver 2.5 watts before the core saturates (to provide some level of voltage regulation). Further down the page is a "Low Speed Power" graph, which shows that most can produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo will deliver 4.0 watts, but that would require buying one of the few better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph). If I were designing or sizing a lighting system suitable for my slow style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0 watt figures. I don't know about currents but 6V 4W bulbs for standard dynamo systems have been around for twenty years and some customers like them. I don't know if the dynamo drag is noticeably greater. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
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On Sunday, March 5, 2017 at 5:26:18 PM UTC-8, Jeff Liebermann wrote:
On Sun, 5 Mar 2017 16:03:30 -0800 (PST), wrote: Thanks Jeff. These however all appear to be battery powered lights. We were sort of looking for lights that operated on the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or four times the power. Sorry, I thought you were still open to looking at battery powered lights. Here's what I fished out of my bookmark dumpster. No reviews and few tests, but some interesting dynamo graphs and numbers: http://www.myra-simon.com/bike/dynotest.html http://pilom.com/BicycleElectronics/DynamoCircuits.htm http://www.eeweb.com/blog/extreme_circuits/power-mosfet-bridge-rectifier This one is well worth reading (or skimming) and has quite a few test results: http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html This is why the hub generator has so little drag. Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. You might find it useful to know how bright you want your light. For that, you'll need a Lux meter. I have a Lutron LX-102 which works nicely, and two junk meters I bought on eBay for sanity checks: http://www.ebay.com/sch/i.html?_nkw=lux+meter Get one that has a wide range. Lowest on mine is 1000 lux, and highest range is 50,000 lux. Find a dark night and an accomplice to operate the meter and send them down the road to the farthest distance that you might want to illuminate with your headlight. Use a headlight or flashlight to light up that area. Have your accompli's take a reading. It will probably be zero. Now, cut the distance in half and take a measurement. It will be 2x as bright (lux) at half the distance or 4x as bright at 1/4th the distance. Adjust the brightness for what it would have been if the light meter was sufficiently sensitive. Converting the brightness (lux) to luminous flux (lumens) requires that you know the distance to the accomplice, and the illumination angle. (1 lux = 1 lumen/square-meter) The form below makes a mess of bad assumptions but is good enough for a rough approximation: https://www.ledrise.com/shop_content.php?coID=19 Once you know how many lumens you think you need, and have adjusted for overly ambitious expectations, you can determine which lighting technology is suitable. Lets say you want to see 8 meters ahead and 20 degrees to each side (or 40 degree conical beamwidth) at 20 lux, which is rather dim. Plugging into the web page above, I get 485 lumens needed. You won't be able to do that with a 3w dynamo, but might squeeze by with a 6w and an oval shaped beam. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 As a very occasional night rider I am interested in battery powered lights but I think that I was attempting to give a thought to a commuter that would use his light a great deal. I notice that a large number of the people in our group have flashing red rear lights and it isn't long before these batteries run down enough that the taillight even blinking is almost entirely unnoticeable. So I don't have much respect for battery power for a great deal of use. |
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On Monday, March 6, 2017 at 1:47:41 PM UTC-5, wrote:
On Sunday, March 5, 2017 at 5:26:18 PM UTC-8, Jeff Liebermann wrote: Snipped I notice that a large number of the people in our group have flashing red rear lights and it isn't long before these batteries run down enough that the taillight even blinking is almost entirely unnoticeable. So I don't have much respect for battery power for a great deal of use. I have a rear red light I bought from MEC (Mountain Equipment Co-op)along with a front light that came with the five AAA batteries (2= rear, 3 = front)that were less than $15.00 for the pair and that rear light on flashing mode lasts for months and I do a LOT of night time riding. Cheers |
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On Sunday, March 5, 2017 at 9:57:44 PM UTC-8, James wrote:
On 06/03/17 10:22, Barry Beams wrote: Burn time: What if you had five or ten hours battery time at your generator's brightness? My Oculus gives at least that much brightness, and a quickly field replaceable battery so you can put in a fresh battery. Other rechargeables leave you out of light and out of luck when the battery drains. Oculus also comes with a spare battery included. What if I don't want to play with batteries? Then you're done with the battery light discussion and may move on to helmets. -- Jay Beattie. |
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On Monday, March 6, 2017 at 2:15:56 PM UTC-5, jbeattie wrote:
On Sunday, March 5, 2017 at 9:57:44 PM UTC-8, James wrote: On 06/03/17 10:22, Barry Beams wrote: Burn time: What if you had five or ten hours battery time at your generator's brightness? My Oculus gives at least that much brightness, and a quickly field replaceable battery so you can put in a fresh battery. Other rechargeables leave you out of light and out of luck when the battery drains. Oculus also comes with a spare battery included. What if I don't want to play with batteries? Then you're done with the battery light discussion and may move on to helmets. -- Jay Beattie. or carbon frames versus steel frames. Cheers |
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On Monday, March 6, 2017 at 1:37:23 PM UTC-5, AMuzi wrote:
On 3/6/2017 11:22 AM, Jeff Liebermann wrote: On Mon, 6 Mar 2017 17:04:13 +1100, James wrote: On 06/03/17 12:26, Jeff Liebermann wrote: Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. We know that a 3W dynamo is quite capable of delivering more power than 3W, once the bicycle speed increases. 6W from a 3W dynamo is quite achievable, and the retardation torque drops off as speed increases too. Maybe: http://www.myra-simon.com/bike/dynotest.html See "Electrical Output" graph. Kinda looks like all of them will sorta deliver 2.5 watts before the core saturates (to provide some level of voltage regulation). Further down the page is a "Low Speed Power" graph, which shows that most can produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo will deliver 4.0 watts, but that would require buying one of the few better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph). If I were designing or sizing a lighting system suitable for my slow style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0 watt figures. I don't know about currents but 6V 4W bulbs for standard dynamo systems have been around for twenty years and some customers like them. I don't know if the dynamo drag is noticeably greater. 6V 4W? I'm aware of 6V 3W bulbs, which are (or were) used mostly with bottle dyno systems when driving a headlamp but no taillamp. They were an alternative to 2.4 W in front and 0.6W in back. I'm not aware of any common use of 6V 4W bulbs. - Frank Krygowski |
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Frank Krygowski wrote:
:On Monday, March 6, 2017 at 1:37:23 PM UTC-5, AMuzi wrote: : On 3/6/2017 11:22 AM, Jeff Liebermann wrote: : On Mon, 6 Mar 2017 17:04:13 +1100, James : wrote: : : On 06/03/17 12:26, Jeff Liebermann wrote: : : Well, let's do some arithmetic. If your dynamo is rated at 3 watts, : and your lighting is rated at 70 lumens/watt, then the most you can : perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. : Usually, it's less as the losses accumulate. Rectification losses, : optical losses, heat degradation, and connector losses all conspire to : produce lower output. : : We know that a 3W dynamo is quite capable of delivering more power than : 3W, once the bicycle speed increases. 6W from a 3W dynamo is quite : achievable, and the retardation torque drops off as speed increases too. : : Maybe: : http://www.myra-simon.com/bike/dynotest.html : See "Electrical Output" graph. : : Kinda looks like all of them will sorta deliver 2.5 watts before the : core saturates (to provide some level of voltage regulation). Further : down the page is a "Low Speed Power" graph, which shows that most can : produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo : will deliver 4.0 watts, but that would require buying one of the few : better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph). : : If I were designing or sizing a lighting system suitable for my slow : style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0 : watt figures. : : : : I don't know about currents but 6V 4W bulbs for standard : dynamo systems have been around for twenty years and some : customers like them. I don't know if the dynamo drag is : noticeably greater. :6V 4W? I'm aware of 6V 3W bulbs, which are (or were) used mostly with bottle :dyno systems when driving a headlamp but no taillamp. They were an alternative :to 2.4 W in front and 0.6W in back. :I'm not aware of any common use of 6V 4W bulbs. It's a standard lantern size. -- But all of a sudden Igor Stravinsky shows up with bag of psilocybin mushrooms and a chainsaw.... -- Jens |
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On 06/03/2017 2:45 PM, Sir Ridesalot wrote:
On Monday, March 6, 2017 at 2:15:56 PM UTC-5, jbeattie wrote: On Sunday, March 5, 2017 at 9:57:44 PM UTC-8, James wrote: On 06/03/17 10:22, Barry Beams wrote: Burn time: What if you had five or ten hours battery time at your generator's brightness? My Oculus gives at least that much brightness, and a quickly field replaceable battery so you can put in a fresh battery. Other rechargeables leave you out of light and out of luck when the battery drains. Oculus also comes with a spare battery included. What if I don't want to play with batteries? Then you're done with the battery light discussion and may move on to helmets. -- Jay Beattie. or carbon frames versus steel frames. Cheers I was hoping for bike lanes... |
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What if I don't want to play with batteries? Then you're done with the battery light discussion and may move on to helmets. or carbon frames versus steel frames. Stainless!!! http://gearpatrol.com/2017/01/26/bes...l-bike-makers/ |
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On 2017-03-06 10:47, wrote:
On Sunday, March 5, 2017 at 5:26:18 PM UTC-8, Jeff Liebermann wrote: On Sun, 5 Mar 2017 16:03:30 -0800 (PST), wrote: Thanks Jeff. These however all appear to be battery powered lights. We were sort of looking for lights that operated on the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or four times the power. Sorry, I thought you were still open to looking at battery powered lights. Here's what I fished out of my bookmark dumpster. No reviews and few tests, but some interesting dynamo graphs and numbers: http://www.myra-simon.com/bike/dynotest.html http://pilom.com/BicycleElectronics/DynamoCircuits.htm http://www.eeweb.com/blog/extreme_circuits/power-mosfet-bridge-rectifier This one is well worth reading (or skimming) and has quite a few test results: http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html This is why the hub generator has so little drag. Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. You might find it useful to know how bright you want your light. For that, you'll need a Lux meter. I have a Lutron LX-102 which works nicely, and two junk meters I bought on eBay for sanity checks: http://www.ebay.com/sch/i.html?_nkw=lux+meter Get one that has a wide range. Lowest on mine is 1000 lux, and highest range is 50,000 lux. Find a dark night and an accomplice to operate the meter and send them down the road to the farthest distance that you might want to illuminate with your headlight. Use a headlight or flashlight to light up that area. Have your accompli's take a reading. It will probably be zero. Now, cut the distance in half and take a measurement. It will be 2x as bright (lux) at half the distance or 4x as bright at 1/4th the distance. Adjust the brightness for what it would have been if the light meter was sufficiently sensitive. Converting the brightness (lux) to luminous flux (lumens) requires that you know the distance to the accomplice, and the illumination angle. (1 lux = 1 lumen/square-meter) The form below makes a mess of bad assumptions but is good enough for a rough approximation: https://www.ledrise.com/shop_content.php?coID=19 Once you know how many lumens you think you need, and have adjusted for overly ambitious expectations, you can determine which lighting technology is suitable. Lets say you want to see 8 meters ahead and 20 degrees to each side (or 40 degree conical beamwidth) at 20 lux, which is rather dim. Plugging into the web page above, I get 485 lumens needed. You won't be able to do that with a 3w dynamo, but might squeeze by with a 6w and an oval shaped beam. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 As a very occasional night rider I am interested in battery powered lights but I think that I was attempting to give a thought to a commuter that would use his light a great deal. I use my lights a great deal because they are on during the day as well except on segregated bike paths. Recharging is 2nd nature to me. Bike gets parked back in the garage, li'l round connector gets plugged in, done. Sometimes I deliberately do not charge past 8V until shortly before a ride. That improves battery lifetime. The real McCoy would be a worryfree system like in a car where it recharges while riding. If I ever switch the road bike front wheel to one with a hub dynamo I will do that. Right now it only has a bottle dynamo, too much drag and it eats the left side wall of "modern" tires. Power output of those is well above 3W at higher speeds if you provide the proper electronics. I could go into that but it's nerdy tech stuff. Essentially you need what is called a SEPIC or at least a buck converter plus some sort of maximum power point tracking (MPPT) control for that converter. Sounds more complicated than it really is but do not expect the bicycle industry to deliver anything even remotely close anytime soon. Realistically you could eke out 4-6W depending on you speed. That's not enough to feed a MagicShine clone which wants 8W on high plus a watt or so for the rear lights. And maybe another 1-2W for the MP3 player. Plus the smart phone. And the electric razor :-) In my case this would work nicely because I need the full 10W total only on county roads and in city areas where car drivers tend to misbehave. Else it drops to a net load of 4-5W or even much lower. So the dynamo would recharge the watt-hours you used up on the county road. Once the battery gets full it throttles back. Just like in car. I notice that a large number of the people in our group have flashing red rear lights and it isn't long before these batteries run down enough that the taillight even blinking is almost entirely unnoticeable. So I don't have much respect for battery power for a great deal of use. Yep, that's a major nuisance. However ... one can power these lights off a regular 8.4V Li-Ion battery or even a dynamo (after rectification) by providing a 3V regulator. Small enough to fit where the two AAA cells used to be. If battery rear lights at least had a low-battery warning. Technically that would be a piece of cake. But no ... nothing :-( -- Regards, Joerg http://www.analogconsultants.com/ |
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On 2017-03-06 13:03, Doug Landau wrote:
What if I don't want to play with batteries? Then you're done with the battery light discussion and may move on to helmets. or carbon frames versus steel frames. Stainless!!! http://gearpatrol.com/2017/01/26/bes...l-bike-makers/ Nah, wood! https://connorcycles.com/ -- Regards, Joerg http://www.analogconsultants.com/ |
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On Mon, 6 Mar 2017 20:10:38 +0000 (UTC), David Scheidt
wrote: Frank Krygowski wrote: :On Monday, March 6, 2017 at 1:37:23 PM UTC-5, AMuzi wrote: : I don't know about currents but 6V 4W bulbs for standard : dynamo systems have been around for twenty years and some : customers like them. I don't know if the dynamo drag is : noticeably greater. :6V 4W? I'm aware of 6V 3W bulbs, which are (or were) used mostly with bottle :dyno systems when driving a headlamp but no taillamp. They were an alternative :to 2.4 W in front and 0.6W in back. :I'm not aware of any common use of 6V 4W bulbs. It's a standard lantern size. http://www.rayovacindustrial.com/Products/Lights/Bulbs/K13-2TB-Krypton-Bulb-for-4D-Flashlights.aspx Ray-0-Vac K13-2TB. Made for 4D cell lanterns. 6v 3.6 watts. I couldn't find a 4 watt version. Most of what I found were 2.4 and 3.0 watt bulbs for bicycles. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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On Mon, 6 Mar 2017 10:47:34 -0800 (PST), wrote:
As a very occasional night rider I am interested in battery powered lights but I think that I was attempting to give a thought to a commuter that would use his light a great deal. Do "occasional night riders" buy $150 headlights? I notice that a large number of the people in our group have flashing red rear lights and it isn't long before these batteries run down enough that the taillight even blinking is almost entirely unnoticeable. So I don't have much respect for battery power for a great deal of use. Well, that's one of the advantages of a dynamo. You never have to worry about a dead or discharged battery or remember to carry a spare dead or discharged battery. (Yes, I've done that). I think you'll find a fair number of riders in your group using low cost rear flashers like this: http://www.ebay.com/itm/142066277090 $0.97 gets you a two AAA batteries packaged inside a flasher (postage included). That's about the same price as the batteries, assuming that they're alkaline and not carbon-zinc. One of my friends says that he picks them out of the trash at the end of club rides because people just toss them instead of trying to figure out how to pry open the case and change the battery. It wouldn't do them much good even if it was easy to open, because the COB (chip on board) electronics, buried under a blob of epoxy, will self destruct if you touch, bend, or push on it. As for not noticing a failure, most club riders will inform your if they see a problem. I don't think it's fair to compare a $150 headlight, with a $0.97 tail light. Others have mentioned various schemes to get more out of a tail light. There are tail lights available or under design that have motion sensors, LiIon battery, low battery indicator, solar charging, USB charging, dynamo charging, wireless charging, side lighting, programmable flashing, high brightness daylight mode, motion alarm, automobile tailgating detection (via a bright headlight detector), Bluegoof telemetry, and whatever else I forgot. Of course, they don't cost $0.97. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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On 3/5/2017 5:26 PM, Jeff Liebermann wrote:
On Sun, 5 Mar 2017 16:03:30 -0800 (PST), wrote: Thanks Jeff. These however all appear to be battery powered lights. We were sort of looking for lights that operated on the hub dynamo of 6V 3W or the Globe dynamo of 12V 6W or four times the power. Sorry, I thought you were still open to looking at battery powered lights. Here's what I fished out of my bookmark dumpster. No reviews and few tests, but some interesting dynamo graphs and numbers: http://www.myra-simon.com/bike/dynotest.html http://pilom.com/BicycleElectronics/DynamoCircuits.htm http://www.eeweb.com/blog/extreme_circuits/power-mosfet-bridge-rectifier This one is well worth reading (or skimming) and has quite a few test results: http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html This is why the hub generator has so little drag. Well, let's do some arithmetic. If your dynamo is rated at 3 watts, and your lighting is rated at 70 lumens/watt, then the most you can perhaps deliver is 210 lumens. 6 watts will get perhaps 420 lumens. Usually, it's less as the losses accumulate. Rectification losses, optical losses, heat degradation, and connector losses all conspire to produce lower output. WE passed 70 lumens per watt a long time ago.http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Arrays-Directional/XLamp-MKR. And bicycle light manufacturers are early adopters of the latest LEDs. A dynamo can produce more than 3 watts at high speeds. In the olden days of incandescent dynamo lights there was protection circuitry to limit the power to the bulb by cutting off the voltage over 6V. But these high power LEDs can handle 15W so there's no need to limit the power. This light http://supernova-lights.com/en/supernova-e3-triple-2 claims 640 lumens at 4.5W. 4.5W is definitely possible from a nominal 3W dynamo. It claims 800 lumens peak. Note that his light, while sold in Germany, is not "road legal." because, according to reviews, it doesn't suffer the problems of StVZO lights, "It has a very broad light output that is closer to a floodlight than a focused beam, and so doesn’t give the ‘tunnel’ effect of some of the powerful battery-powered lights. This means it’s great for illuminating branches and hazards above you and off to the side." As we all know, the problem with StVZO legal lights are related to the extremely focused spot beam. The best option, to avoid annoying others, is to not use the highest settings when riding on narrow roads or paths. You don't want endanger yourself by using sub-par StVZO lights unless it's mandated by law. |
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On Mon, 6 Mar 2017 18:37:14 -0800, sms
wrote: WE passed 70 lumens per watt a long time ago.http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Arrays-Directional/XLamp-MKR. And bicycle light manufacturers are early adopters of the latest LEDs. I got burned badly when I specified an LED that was rated at 100 lumens/watt, and got something that was about 70 lumens/watt. If you look at the Xlamp MK-R data sheet at: http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/Data-and-Binning/XLampMKR.pdf the footknots always says: "Flux values @25*°C are calculated and for reference only." I'm not sure exactly what that means, but from my limited experience, it means that if you pulse the power to the LED with a very short duty cycle, you might get something near the rated efficacy. If you run it on DC, it won't even come close. Calculated also means that they didn't bother to verify their own calculations with an integrating sphere measurement. Assuming 200 lumens/watt and 1000 lumens output, that would require 5 watts of input power. Looking at the same data sheet (Pg 15) the 6v chart shows that 5w is 5.8v @ 0.85A. So far, so good. However, if we look at the Relative Flux Vs. Current (tJ = 85*°C) graph on Pg 16, the output is derated to 65% of 1000 lumens. Producing only 650 lumens. Using those numbers, the efficacy is now: 650 lumens / 5 watts = 130 lumens/watt Note that the 85C is the junction temp, not the case or heat sink temp. Then, there is matching LED chips. See Pg 20 "Performance Groups - Luminous Flux (Tj = 85*°C)" where one can pick the chip output anywhere from about 515 to 1290 lumens. What is not obvious is that the efficiency also drops at the lower output levels, resulting in even lower lumens/watt. Then there's the loss in output due to reflectors and lenses and the increase of input current from current regulator losses. I would guess(tm) 15% loss of lumens to the optics, and 10% for the regulator efficiency. So, we start with 650 lumens / 5 watts = 130 lumens/watt and end up with: 650 * 0.85 / 5 * 1.1 = 553 / 5.5 = 100 lumens/watt Can you see where this is going? In the end, the lumens/watt value for the end product is the light output including all the optics, divided by the power input as measured from the battery, and derated by the chip junction temperature. A dynamo can produce more than 3 watts at high speeds. I don't ride at high speeds. I'm slowly converting one of my machines to a "comfort" bicycle. In the olden days of incandescent dynamo lights there was protection circuitry to limit the power to the bulb by cutting off the voltage over 6V. But these high power LEDs can handle 15W so there's no need to limit the power. Yep. So why do many dynamos still use the increased inductive reactance at higher speeds (and higher frequencies) to provide this voltage limiting? It would be easy enough to reduce the winding inductance and allow the voltage to increase linearly instead of flat-topping. The manufacturer might be afraid of blowing something up with too much voltage at high speeds. This light http://supernova-lights.com/en/supernova-e3-triple-2 claims 640 lumens at 4.5W. 4.5W is definitely possible from a nominal 3W dynamo. It claims 800 lumens peak. 640 lumens / 4.5 watts = 142 lumens/watt measured "warm". If they start out with a 200 lumens/wall LED, that might be possible. Ok, I stand corrected, but I'm also suspicious. I couldn't find any test reports or method used on the Supernova site. I did find this test of the M99 model: http://supernova-lights.com/en/blog/supernova-blog-1/post/first-test-performance-supernova-m99-pro-br-36 1100 lumens / 16 watts = 68.7 lumens/watt. Hmmm... -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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On 3/6/2017 4:33 PM, Joerg wrote:
The real McCoy would be a worryfree system like in a car where it recharges while riding. If I ever switch the road bike front wheel to one with a hub dynamo I will do that. Right now it only has a bottle dynamo, too much drag and it eats the left side wall of "modern" tires. I've done well with a bottle dynamo whose drive wheel has an added circumferential groove to hold a thick O-ring. That O-ring runs on the rim's braking surface, not on the tire. Zero tire wear, and it runs very smoothly. I've experienced no slipping - but it's not been tested in the rain. -- - Frank Krygowski |
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On Mon, 6 Mar 2017 16:57:41 +1100, James
wrote: What if I don't want to play with batteries? Then play with calcium carbide (produces acetylene gas) instead: https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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On 3/6/2017 9:37 PM, sms wrote:
This light http://supernova-lights.com/en/supernova-e3-triple-2 claims 640 lumens at 4.5W. 4.5W is definitely possible from a nominal 3W dynamo. It claims 800 lumens peak. Note that his light, while sold in Germany, is not "road legal." because, according to reviews, it doesn't suffer the problems of StVZO lights, "It has a very broad light output that is closer to a floodlight than a focused beam, and so doesn’t give the ‘tunnel’ effect of some of the powerful battery-powered lights. This means it’s great for illuminating branches and hazards above you and off to the side." As we all know, the problem with StVZO legal lights are related to the extremely focused spot beam. Here's an example of an StVZO headlamp (2013 model) with the "extremely focused spot beam" the Scharf complains about. http://peterwhitecycles.com/images/p...lux-II-800.jpg See that tiny spot? ;-) -- - Frank Krygowski |
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On Mon, 6 Mar 2017 23:11:26 -0500, Frank Krygowski
wrote: Here's an example of an StVZO headlamp (2013 model) with the "extremely focused spot beam" the Scharf complains about. http://peterwhitecycles.com/images/p...lux-II-800.jpg See that tiny spot? ;-) Here's the same photo with brightness converted to pseudo colors: http://802.11junk.com/jeffl/pics/bicycles/Front-Light-False-Color/sch-edelux-II-800.jpg No obvious hot spot. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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never experiencing dyna lighting, the White photo bears no relation to anything I've read here.
I aaside the cycle is moving at 35 mph. |
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On Tuesday, March 7, 2017 at 5:11:29 AM UTC+1, Frank Krygowski wrote:
On 3/6/2017 9:37 PM, sms wrote: This light http://supernova-lights.com/en/supernova-e3-triple-2 claims 640 lumens at 4.5W. 4.5W is definitely possible from a nominal 3W dynamo. It claims 800 lumens peak. Note that his light, while sold in Germany, is not "road legal." because, according to reviews, it doesn't suffer the problems of StVZO lights, "It has a very broad light output that is closer to a floodlight than a focused beam, and so doesn’t give the ‘tunnel’ effect of some of the powerful battery-powered lights. This means it’s great for illuminating branches and hazards above you and off to the side." As we all know, the problem with StVZO legal lights are related to the extremely focused spot beam. Here's an example of an StVZO headlamp (2013 model) with the "extremely focused spot beam" the Scharf complains about. http://peterwhitecycles.com/images/p...lux-II-800.jpg See that tiny spot? ;-) -- - Frank Krygowski That is the headlight I use and it looks exactly the same on a pitch dark street. So again I don't understand why people find this amount of light insufficient. Lou |
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On Mon, 6 Mar 2017 11:15:54 -0800 (PST), jbeattie
wrote: On Sunday, March 5, 2017 at 9:57:44 PM UTC-8, James wrote: On 06/03/17 10:22, Barry Beams wrote: Burn time: What if you had five or ten hours battery time at your generator's brightness? My Oculus gives at least that much brightness, and a quickly field replaceable battery so you can put in a fresh battery. Other rechargeables leave you out of light and out of luck when the battery drains. Oculus also comes with a spare battery included. What if I don't want to play with batteries? Then you're done with the battery light discussion and may move on to helmets. -- Jay Beattie. I thought that chain-lube was next on the agenda? -- Cheers, John B. |
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On Mon, 06 Mar 2017 20:10:21 -0800, Jeff Liebermann
wrote: On Mon, 6 Mar 2017 16:57:41 +1100, James wrote: What if I don't want to play with batteries? Then play with calcium carbide (produces acetylene gas) instead: https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch Ahem! I don't think you should suggest acetylene gas devices to some of the folks here. After all the safe limit for acetylene gas is 15 psi, above which it tends to go BOOM! :-) (but maybe if you wear a helmet and have a bright light... :-) -- Cheers, John B. |
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On 2017-03-06 20:00, Frank Krygowski wrote:
On 3/6/2017 4:33 PM, Joerg wrote: The real McCoy would be a worryfree system like in a car where it recharges while riding. If I ever switch the road bike front wheel to one with a hub dynamo I will do that. Right now it only has a bottle dynamo, too much drag and it eats the left side wall of "modern" tires. I've done well with a bottle dynamo whose drive wheel has an added circumferential groove to hold a thick O-ring. That O-ring runs on the rim's braking surface, not on the tire. Zero tire wear, and it runs very smoothly. I've experienced no slipping - but it's not been tested in the rain. May main issue isn't rain but mud. Often the Soubitez bottle dynamo on my road bike mutates into a clump of drying clay. Back in Europe slush and ice was the main issue. Typically on a night ride back home when a cold front rushed in. The slush accumulated at the dynamo, gradually froze up there and at some point ... phseeeee ... no more light on our bikes except on mine because that had a battery. -- Regards, Joerg http://www.analogconsultants.com/ |
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On Tue, 07 Mar 2017 20:00:47 +0700, John B.
wrote: On Mon, 06 Mar 2017 20:10:21 -0800, Jeff Liebermann wrote: On Mon, 6 Mar 2017 16:57:41 +1100, James wrote: What if I don't want to play with batteries? Then play with calcium carbide (produces acetylene gas) instead: https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch Ahem! I don't think you should suggest acetylene gas devices to some of the folks here. After all the safe limit for acetylene gas is 15 psi, above which it tends to go BOOM! :-) I once found a patent for an acetylene lantern design that used the heated gas pressure from the burning acetylene to pressurize a reed and thus act as a horn. I don't recall if it had a built in red tail light. What keeps an acetylene lantern from blowing up and ruining a ride is that the drip of water into the calcium carbide chamber is regulated by the back pressure produced by the reaction. No water means no gas is produced. It's a gravity fed affair, that's quite reliable and should never raise the internal pressure anywhere near 15 psig. (but maybe if you wear a helmet and have a bright light... :-) The light isn't for me. It's for James who wants an alternative to changing batteries. I solved my lighting problem long ago: http://802.11junk.com/jeffl/pics/bicycles/slides/bicycle-flashlight.html The big problem with an acetylene bicycle lantern is that a typical lantern only delivers about 30 to 50 lumens (my measurements). If you need a project, build an acetylene lamp that screws into an aluminum water bottle. http://www.4bobandbob.com/pages/pics/PremierDia.gif -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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