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#1
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Any comments on the Supernova Infinity dynamo hub
I ran across this particular dyno hub
http://www.supernova-lights.com/en/products/infinity_8.html while scouring the web for a dynamo hub (hey, Google search sometimes works...). Does anybody have any experience with this manufacturer's product? |
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#2
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Any comments on the Supernova Infinity dynamo hub
On 28/09/2011 14:45, Ralph Barone wrote:
I ran across this particular dyno hub http://www.supernova-lights.com/en/products/infinity_8.html while scouring the web for a dynamo hub (hey, Google search sometimes works...). Does anybody have any experience with this manufacturer's product? No, but it does look a bit like a solution in search of a problem. Even the worst of the old Shimano dynohubs gives barely any drag. It also means you can't simply switch on while riding (tunnels, etc) or have fit-and-forget autosensing lights. And it costs more than a SON. One point of interest though is the development of LED dynamo lights has allowed this hub to do its other thing - plug it into a halogen set, and bulbs would be blowing. That curve of voltage againsts speed doesn't show it's superior, it shows it's worse-regulated. But for a modern LED lamp with clever electronics, that doesn't actually matter. |
#3
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Any comments on the Supernova Infinity dynamo hub
Clive George wrote:
On 28/09/2011 14:45, Ralph Barone wrote: I ran across this particular dyno hub http://www.supernova-lights.com/en/products/infinity_8.html while scouring the web for a dynamo hub (hey, Google search sometimes works...). Does anybody have any experience with this manufacturer's product? No, but it does look a bit like a solution in search of a problem. Even the worst of the old Shimano dynohubs gives barely any drag. It also means you can't simply switch on while riding (tunnels, etc) or have fit-and-forget autosensing lights. And it costs more than a SON. One point of interest though is the development of LED dynamo lights has allowed this hub to do its other thing - plug it into a halogen set, and bulbs would be blowing. That curve of voltage againsts speed doesn't show it's superior, it shows it's worse-regulated. But for a modern LED lamp with clever electronics, that doesn't actually matter. Do you have any details on the "clever electronics" in modern LED generator lamps? I ask because one can get by with very little in the way of electronics. Bike dynamos (or generators) are, to a good approximation, constant current devices, in the same way that batteries are, to a good approximation, constant voltage devices. LEDs need regulated current, which is exactly what they naturally get from a dynamo. Rectification and/or protection from excessive back voltage doesn't take much cleverness, and a standlight, for those who want it, isn't much more complicated. So what's in a dynamo LED headlight? Is it more than a diode bridge and a big capacitor? -- - Frank Krygowski |
#4
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Any comments on the Supernova Infinity dynamo hub
Clive George wrote:
:On 28/09/2011 14:45, Ralph Barone wrote: : I ran across this particular dyno hub : http://www.supernova-lights.com/en/products/infinity_8.html while : scouring the web for a dynamo hub (hey, Google search sometimes : works...). Does anybody have any experience with this manufacturer's : product? :No, but it does look a bit like a solution in search of a problem. Even :the worst of the old Shimano dynohubs gives barely any drag. It also :means you can't simply switch on while riding (tunnels, etc) or have :fit-and-forget autosensing lights. And it costs more than a SON. They're made by a tiawanese company, Shutter precision. Essentially the same dyanmo is available from other people. (for less money). I believe the design doesn't actually turn the dynamo off entirely, but moves the outer part farther away from the axle, reducing its output. I can't find their patent for it, which I've been told they've got. I do find their patent on the super small one, which uses powerful magnets. -- sig 7 |
#5
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Any comments on the Supernova Infinity dynamo hub
On Sep 28, 11:21*am, David Scheidt wrote:
Clive George wrote: :On 28/09/2011 14:45, Ralph Barone wrote: : I ran across this particular dyno hub : http://www.supernova-lights.com/en/products/infinity_8.html *while : scouring the web for a dynamo hub (hey, Google search sometimes : works...). *Does anybody have any experience with this manufacturer's : product? :No, but it does look a bit like a solution in search of a problem. Even :the worst of the old Shimano dynohubs gives barely any drag. It also :means you can't simply switch on while riding (tunnels, etc) or have :fit-and-forget autosensing lights. And it costs more than a SON. They're made by a tiawanese company, Shutter precision. *Essentially the same dyanmo is available from other people. *(for less money). *I believe the design doesn't actually turn the dynamo off entirely, but moves the outer part farther away from the axle, reducing its output. I can't find their patent for it, which I've been told they've got. *I do find their patent on the super small one, which uses powerful magnets. * I know it is sold through Velo Orange -- for less than a SON, but I don't know where else it is sold. -- Jay Beattie. |
#6
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Any comments on the Supernova Infinity dynamo hub
On 9/28/2011 6:45 AM, Ralph Barone wrote:
I ran across this particular dyno hub http://www.supernova-lights.com/en/products/infinity_8.html while scouring the web for a dynamo hub (hey, Google search sometimes works...). Does anybody have any experience with this manufacturer's product? I saw it (or someone else's switchable hub) at Interbike on one of the Tern models, and got a photo of it: http://nordicgroup.us/interbike2011/img_3150.jpg. I think the hub in the Tern model is this one: http://www.sp-dynamo.com/spproductswitchdisc.html. Given Tern's desire to move upscale in folders, and knowing Josh Hon, I'd be surprised if he used any really crappy components on his new line. The specs for the Tern model with the Shutter Precision dynamo hub are at http://www.ternbicycles.com/bikes/eclipse-s11i?quicktabs_bike_tabs=2#quicktabs-bike_tabs. Very good idea since the drag on those dynamo hubs when engaged, even when the lights are off and the hub is not generating any power, is significant. Fortunately these switchable hubs are not very expensive either. So rather than spend the big bucks on a Son, you can achieve even less drag for a lot less money. |
#7
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Any comments on the Supernova Infinity dynamo hub
On 29/09/2011 10:07, SMS wrote:
Very good idea since the drag on those dynamo hubs when engaged, even when the lights are off and the hub is not generating any power, is significant. That's just utter nonsense. The drag is insignificant, even when generating. |
#8
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Any comments on the Supernova Infinity dynamo hub
On 29 sep, 16:23, Clive George wrote:
On 29/09/2011 10:07, SMS wrote: Very good idea since the drag on those dynamo hubs when engaged, even when the lights are off and the hub is not generating any power, is significant. That's just utter nonsense. The drag is insignificant, even when generating. Would I have a dynahub light system if there were significant drag when generating? Would I leave my front wheel with dynahub on my bike during summer season when there was significant drag when not generating? Hell no. I do have dynahub light systems and leave my front wheel on my bike in summer season. So it is utter nonsense and the supernova hub solves a non existing problem introducing more complexity and inconvenience. Lou |
#9
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Any comments on the Supernova Infinity dynamo hub
SMS wrote:
:Very good idea since the drag on those dynamo hubs when engaged, even :when the lights are off and the hub is not generating any power, is :significant. Fortunately these switchable hubs are not very expensive No, it's not. It is if you're in danger of losing the race by half a second, but not otherwise. There's lots of *perceived* drag, but most of that is given back. The actual drag is low. -- This is a randomly numbered sig. |
#10
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Any comments on the Supernova Infinity dynamo hub
On 9/29/2011 7:42 AM, Lou Holtman wrote:
On 29 sep, 16:23, Clive wrote: On 29/09/2011 10:07, SMS wrote: Very good idea since the drag on those dynamo hubs when engaged, even when the lights are off and the hub is not generating any power, is significant. That's just utter nonsense. The drag is insignificant, even when generating. Would I have a dynahub light system if there were significant drag when generating? Yes, because the alternative, up until now, has been unacceptable. Would I leave my front wheel with dynahub on my bike during summer season when there was significant drag when not generating? Yes. Hell no. I do have dynahub light systems and leave my front wheel on my bike in summer season. So it is utter nonsense and the supernova hub solves a non existing problem introducing more complexity and inconvenience. You don't realize just how much the extra drag actually is. What you need to do is to compare a dynamo and a non-dynamo wheel, off the bike. Think about it this way. A human can put out about 1/10 HP continuously (around 75W). A dynamo is rated at 3W and actually can put out about 6W. If you're using 3W lights, you're expending about 6W of energy into running the lights. With the lights off, the energy expended goes down, the SON required around 5.4W of input with lights off, and around 5.6W of input power with lights on (for 3W lights). The Shimano Alfine was slightly worse. See http://www.ecovelo.info/2009/11/05/new-dyno-hub-test/. So the question is whether or not "saving" 5W of power in the daytime is worth the extra complexity of a hub dynamo that can disengage the dynamo when not in use. My personal feeling is that since I have my lights on in the daytime anyway (strobe in front, flasher in back) that there's little benefit. But those doing randonneuring may appreciate the savings in power. |
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