Loading ...
Sorry, an error occurred while loading the content.

12 volts hub dynamo

Expand Messages
  • thon_thon
    i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!
    Message 1 of 29 , Sep 3, 2011
    • 0 Attachment
      i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!
    • David Chase
      I am not sure such a thing exists. If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors. Hub dynamos also zoom their
      Message 2 of 29 , Sep 3, 2011
      • 0 Attachment
        I am not sure such a thing exists.

        If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors.
        Hub dynamos also zoom their voltage up if you don't draw "all" of their current.

        I use a voltage doubler feeding a switching power supply, and with a modest current draw I get 20 volts at not much speed.
        (The lights come on solid at 3mph).

        David

        On 2011-09-03, at 9:13 AM, thon_thon wrote:

        > i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!
      • erickson osit
        ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right? ________________________________ From: David Chase
        Message 3 of 29 , Sep 3, 2011
        • 0 Attachment
          ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right?

          From: David Chase <dr2chase@...>
          To: Geared_hub_bikes@yahoogroups.com
          Sent: Saturday, September 3, 2011 10:45 PM
          Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo

           
          I am not sure such a thing exists.

          If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors.
          Hub dynamos also zoom their voltage up if you don't draw "all" of their current.

          I use a voltage doubler feeding a switching power supply, and with a modest current draw I get 20 volts at not much speed.
          (The lights come on solid at 3mph).

          David

          On 2011-09-03, at 9:13 AM, thon_thon wrote:

          > i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!



        • Rich W
          Welcome to the group. I do not know of a hub dynamo rated for more than 6v, 3watts but actual power output can be far more than that at higher speeds. The
          Message 4 of 29 , Sep 3, 2011
          • 0 Attachment
            Welcome to the group.

            I do not know of a hub dynamo rated for more than 6v, 3watts but actual power output can be far more than that at higher speeds. The rated output has to do with German bicycle lighting laws and their requirements for low speed performance. Companies design to meet those laws as Germany is the largest market for dynamo lighting due to it being required on most bicycles sold there.

            Supernova makes a dynamo light set designed to take advantage of it, their triple headlight which puts out a claimed 600 Lumens but not until about 24 MPH per an email discussion I had with Supernova. It is not street legal in Germany.

            If you need a 12VDC output that has some regulation then investigate the E-Werk by Busch & Muller. It may allow you to do what you want.

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

            Note that the manual is downloadable from this site which covers the device capabilities in detail. Not cheap but it might solve your problem.

            Another device is the pedalpower bit it looks like it is limited to 5VDC USB charged device power output.

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

            Busch & Muller does make a 12V 6W bottle dynamo, a very expensive item. There are also some asian cheap bottle dynamos which claim to be 12V 6W. Per posts from one member the B&M dynamo must be mounted in a particular orientation or it is not water resistant apparently.

            Rich Wood

            --- In Geared_hub_bikes@yahoogroups.com, erickson osit <dharickson@...> wrote:
            >
            > ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right?
            >
            >
            > ________________________________
            > From: David Chase <dr2chase@...>
            > To: Geared_hub_bikes@yahoogroups.com
            > Sent: Saturday, September 3, 2011 10:45 PM
            > Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo
            >
            >
            >  
            > I am not sure such a thing exists.
            >
            > If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors.
            > Hub dynamos also zoom their voltage up if you don't draw "all" of their current.
            >
            > I use a voltage doubler feeding a switching power supply, and with a modest current draw I get 20 volts at not much speed.
            > (The lights come on solid at 3mph).
            >
            > David
            >
            > On 2011-09-03, at 9:13 AM, thon_thon wrote:
            >
            > > i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!
            >
          • David Chase
            The hub dynamo is actually a hub alternator. It produces AC, not DC. The power output depends upon how much current you draw, because high current loads will
            Message 5 of 29 , Sep 3, 2011
            • 0 Attachment
              The hub dynamo is actually a hub alternator. It produces AC, not DC.
              The power output depends upon how much current you draw, because high current loads will cause power loss in the hub itself.
              A lower current load, suitably regulated, allows you to run more watts.

              So for example, even at moderate speeds, my lighting system produces 4 watts of light, and at higher speeds comes closer to 8.

              The German regulations seem like they will be overtaken by technical advances; 3 watts of LED light is quite a lot, and tons more than you would get from any halogen bulb. Furthermore, each time they turn the technology crank, the light output increases by another third.

              The question is, what do you NEED? That should be a current and voltage specification; at low currents, you can easily get 25 or more volts from a "6 volt" hub. 20 volts and 200 milliAmps is not hard.

              David

              On 2011-09-03, at 11:57 AM, erickson osit wrote:

              >
              > ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right?
            • David Chase
              ... That was me, and there s no apparently about it. It got a load of water in its power fiddling circuits, and subsequently failed. I got completely
              Message 6 of 29 , Sep 3, 2011
              • 0 Attachment
                On 2011-09-03, at 12:41 PM, Rich W wrote:
                > Busch & Muller does make a 12V 6W bottle dynamo, a very expensive item. There are also some asian cheap bottle dynamos which claim to be 12V 6W. Per posts from one member the B&M dynamo must be mounted in a particular orientation or it is not water resistant apparently.

                That was me, and there's no "apparently" about it. It got a load of water in its power fiddling circuits, and subsequently failed. I got completely unsatisfactory customer service, too.

                David
              • wahooncx@yahoo.com
                The only 12v hub dyno that I am aware of was a very early Sturmey-Archer model from around 1930. Why do you need 12 volts? Sent from my Verizon Wireless
                Message 7 of 29 , Sep 3, 2011
                • 0 Attachment
                  The only 12v hub dyno that I am aware of was a very early Sturmey-Archer model from around 1930. Why do you need 12 volts?



                  Sent from my Verizon Wireless BlackBerry


                  From: erickson osit <dharickson@...>
                  Sender: Geared_hub_bikes@yahoogroups.com
                  Date: Sat, 3 Sep 2011 08:57:26 -0700 (PDT)
                  To: Geared_hub_bikes@yahoogroups.com<Geared_hub_bikes@yahoogroups.com>
                  ReplyTo: Geared_hub_bikes@yahoogroups.com
                  Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo

                   

                  ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right?

                  From: David Chase <dr2chase@...>
                  To: Geared_hub_bikes@yahoogroups.com
                  Sent: Saturday, September 3, 2011 10:45 PM
                  Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo

                   
                  I am not sure such a thing exists.

                  If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors.
                  Hub dynamos also zoom their voltage up if you don't draw "all" of their current.

                  I use a voltage doubler feeding a switching power supply, and with a modest current draw I get 20 volts at not much speed.
                  (The lights come on solid at 3mph).

                  David

                  On 2011-09-03, at 9:13 AM, thon_thon wrote:

                  > i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!



                • pj
                  ... The GH12 debuted in 1936 and was built until the war. Beginning in 1945 Sturmey-Archer built only 6V dynohubs.
                  Message 8 of 29 , Sep 3, 2011
                  • 0 Attachment
                    > The only 12v hub dyno that I am aware of was
                    > a very early Sturmey-Archer model from around
                    > 1930.

                    The GH12 debuted in 1936 and was built until the war. Beginning in 1945 Sturmey-Archer built only 6V dynohubs.

                    <http://www.sturmey-archerheritage.com/images/photos/pic-51.1.jpg>

                    Interesting story about the early days of the dynohub: Sid Ferris had set a new Edinburgh-London record during the long days of the summer of 1937, but upon review the time was disallowed in November because of a rule violation by one of his support team.

                    Determined to include the Edinburgh-London record in his amazing record-setting year, Mr. Ferris scheduled a re-ride in December, when the available daylight was close to annual nadir. Equipping his bike with the new GH12 (and of course the same super-narrow range AR 3-speed hub he'd used in June to set a new Land's End to John O'Groats mark),

                    <http://www.sturmey-archerheritage.com/images/photos/pic-49.1.jpg>

                    he set out in the dark and eventually arrived in London quicker than even the elapsed time of his summer attempt. Sturmey was ecstatic and used this record ride set with the GH12 in advertising to illustrate how little drag the new dynohub created.

                    pj
                  • wahooncx@yahoo.com
                    I knew somebody would straighten me out... Also if memory serves S-A made an 8 volt for a short period of time. I am traveling and can t access the S-A
                    Message 9 of 29 , Sep 3, 2011
                    • 0 Attachment
                      I knew somebody would straighten me out...

                      Also if memory serves S-A made an 8 volt for a short period of time. I am traveling and can't access the S-A heritage site to refresh the memory. :-P

                      Aaron

                      Sent from my Verizon Wireless BlackBerry


                      From: "pj" <prester_john_in_cathay@...>
                      Sender: Geared_hub_bikes@yahoogroups.com
                      Date: Sat, 03 Sep 2011 19:44:48 -0000
                      To: <Geared_hub_bikes@yahoogroups.com>
                      ReplyTo: Geared_hub_bikes@yahoogroups.com
                      Subject: [Geared_hub_bikes] Re: 12 volts hub dynamo

                       

                      > The only 12v hub dyno that I am aware of was
                      > a very early Sturmey-Archer model from around
                      > 1930.

                      The GH12 debuted in 1936 and was built until the war. Beginning in 1945 Sturmey-Archer built only 6V dynohubs.

                      <http://www.sturmey-archerheritage.com/images/photos/pic-51.1.jpg>

                      Interesting story about the early days of the dynohub: Sid Ferris had set a new Edinburgh-London record during the long days of the summer of 1937, but upon review the time was disallowed in November because of a rule violation by one of his support team.

                      Determined to include the Edinburgh-London record in his amazing record-setting year, Mr. Ferris scheduled a re-ride in December, when the available daylight was close to annual nadir. Equipping his bike with the new GH12 (and of course the same super-narrow range AR 3-speed hub he'd used in June to set a new Land's End to John O'Groats mark),

                      <http://www.sturmey-archerheritage.com/images/photos/pic-49.1.jpg>

                      he set out in the dark and eventually arrived in London quicker than even the elapsed time of his summer attempt. Sturmey was ecstatic and used this record ride set with the GH12 in advertising to illustrate how little drag the new dynohub created.

                      pj

                    • thon_thon
                      i need a hub dynamo to generate high voltage and convert it in DC to store it into a storage battery to use it in my other features in my bike! like motors and
                      Message 10 of 29 , Sep 4, 2011
                      • 0 Attachment
                        i need a hub dynamo to generate high voltage and convert it in DC to store it into a storage battery to use it in my other features in my bike! like motors and amplifier!can you give me an idea, how can i do that?

                        --- In Geared_hub_bikes@yahoogroups.com, wahooncx@... wrote:
                        >
                        > The only 12v hub dyno that I am aware of was a very early Sturmey-Archer model from around 1930. Why do you need 12 volts?
                        >
                        >
                        >
                        >
                        > Sent from my Verizon Wireless BlackBerry
                        >
                        > -----Original Message-----
                        > From: erickson osit <dharickson@...>
                        > Sender: Geared_hub_bikes@yahoogroups.com
                        > Date: Sat, 3 Sep 2011 08:57:26
                        > To: Geared_hub_bikes@yahoogroups.com<Geared_hub_bikes@yahoogroups.com>
                        > Reply-To: Geared_hub_bikes@yahoogroups.com
                        > Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo
                        >
                        > ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right?
                        >
                        >
                        > ________________________________
                        > From: David Chase <dr2chase@...>
                        > To: Geared_hub_bikes@yahoogroups.com
                        > Sent: Saturday, September 3, 2011 10:45 PM
                        > Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo
                        >
                        >
                        >  
                        > I am not sure such a thing exists.
                        >
                        > If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors.
                        > Hub dynamos also zoom their voltage up if you don't draw "all" of their current.
                        >
                        > I use a voltage doubler feeding a switching power supply, and with a modest current draw I get 20 volts at not much speed.
                        > (The lights come on solid at 3mph).
                        >
                        > David
                        >
                        > On 2011-09-03, at 9:13 AM, thon_thon wrote:
                        >
                        > > i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!
                        >
                      • chkamb@gmx.de
                        Hi, most hub dynamos deliver more than 6V and have a built in voltage limiter of some sort. If you have a hub dynamo for experiments try to run it without the
                        Message 11 of 29 , Sep 4, 2011
                        • 0 Attachment
                          Hi, most hub dynamos deliver more than 6V and have a built in voltage limiter of some sort. If you have a hub dynamo for experiments try to run it without the limiter... SON delivers almost 12V at speeds higher that 20 km/h..
                          Here is a German page with some insights on 12v dynamos:
                          www.enhydralutris.de/Fahrrad/Beleuchtung/index.html
                          There was one German dynamo (a so called spoke dynamo) with 12V that comes near to a hub dynamo: FER SD 12V. I am searching for it for years - no chance.. (Pictured here: www.pdeleuw.de/fahrrad/beleuchtung.html#dynamo "Speichendynamos").

                          Chris
                        • David Chase
                          You should be fine with a voltage doubler, not sure about the current. Pilom.com has a lot of information that might help you:
                          Message 12 of 29 , Sep 4, 2011
                          • 0 Attachment
                            You should be fine with a voltage doubler, not sure about the current.

                            Pilom.com has a lot of information that might help you:
                            http://www.pilom.com/BicycleElectronics/HubDynamo.htm

                            What I build for voltage doubling looks like a full-wave rectifier (4 diodes in a diamond) with two legs of the diamond (adjacent to one of the AC inputs) augmented with capacitors. About 3900uF for the big filter cap, about 470uF for the leg caps. Schottky diodes, e.g. SB540, are a good choice for the diodes. All the pluses and minuses line up sensibly. You don't really need the diodes next to the leg caps, EXCEPT that you are almost certainly using electrolytic capacitors and those don't like to be reverse-biased (it can happen).

                            Depending on your speed, this will trickle charge your 12-v battery, usually with not more than 1/4 amp (250mA). So if you charge a battery with a 2500 milliAmp-Hour capacity, that's 10 hours to reach full charge. If you ever disconnect the battery, you will also want to disconnect the hub, else you will build up very high (component-frying) voltages in the doubler/smoother.

                            If you need more charge than that, you might want to look into solar. I have a Big Dummy/Xtracycle with a somewhat customized rear deck, and one thing I have intended to do (but never got around to it) was to route out some holes for solar cells (and acrylic covers) so that I could have extra juice (I have Grand Plans, and no time to do them).

                            On 2011-09-04, at 5:34 AM, thon_thon wrote:

                            > i need a hub dynamo to generate high voltage and convert it in DC to store it into a storage battery to use it in my other features in my bike! like motors and amplifier!can you give me an idea, how can i do that?
                          • Paul Toigo
                            How s your German? I interpret that the SON can output 12V at 20km/hr, but never more than 0.5A. From Schmidt s website:
                            Message 13 of 29 , Sep 4, 2011
                            • 0 Attachment

                              How’s your German? I interpret that the SON can output 12V at 20km/hr, but never more than 0.5A. From Schmidt’s website:

                              http://www.nabendynamo.de/service/12volt/12vinfo.html

                              http://www.nabendynamo.de/produkte/pdf/12vinfo.pdf

                              http://www.nabendynamo.de/service/pdf/ar_11-12_2007.pdf

                               

                            • Rich W
                              No one has made what you want commercially that I am aware of. The problem is that for high power output the drag becomes unacceptable as the energy to run
                              Message 14 of 29 , Sep 4, 2011
                              • 0 Attachment
                                No one has made what you want commercially that I am aware of. The problem is that for high power output the drag becomes unacceptable as the energy to run the dynamo has to come from you, the rider. A dynamo able to output enough power to usefully charge motor operating batteries would have tremendous drag. The average good condition bicyclist outputs 100 watts or less average and professionals do not output much more than 250 watts or so average. Many casual cyclists average below 50 watts output.

                                What wattage do you want/need from the whole generator mechanism and how hard are you willing to work to get it? There is no free lunch from a bicycle driven generator/alternator assembly which is why they are currently designed for low power output and relatively low drag. Modern LED lights allow them to work quite effectively to provide light and some add ons such as those I linked to in an earlier post allow charging and use of quite low power electronics.

                                Remember too that AC to DC conversion losses, battery charge/discharge losses, motor efficiency losses etc mean that overall system efficiency is going to probably be in the 50% to 80% range depending on the design. That means even more power needed from the rider to cover system efficiency losses.

                                The reason why what you want is not made is that few riders would be willing to put up with the riding performance loss when the dynamo was outputing at any useful power level for propulsion battery charging or other high power demand operation IMO. It would be like riding up hill all of the time.

                                Rich Wood


                                --- In Geared_hub_bikes@yahoogroups.com, "thon_thon" <dharickson@...> wrote:
                                >
                                > i need a hub dynamo to generate high voltage and convert it in DC to store it into a storage battery to use it in my other features in my bike! like motors and amplifier!can you give me an idea, how can i do that?
                                >
                                > --- In Geared_hub_bikes@yahoogroups.com, wahooncx@ wrote:
                                > >
                                > > The only 12v hub dyno that I am aware of was a very early Sturmey-Archer model from around 1930. Why do you need 12 volts?
                                > >
                                > >
                                > >
                                > >
                                > > Sent from my Verizon Wireless BlackBerry
                                > >
                                > > -----Original Message-----
                                > > From: erickson osit <dharickson@>
                                > > Sender: Geared_hub_bikes@yahoogroups.com
                                > > Date: Sat, 3 Sep 2011 08:57:26
                                > > To: Geared_hub_bikes@yahoogroups.com<Geared_hub_bikes@yahoogroups.com>
                                > > Reply-To: Geared_hub_bikes@yahoogroups.com
                                > > Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo
                                > >
                                > > ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right?
                                > >
                                > >
                                > > ________________________________
                                > > From: David Chase <dr2chase@>
                                > > To: Geared_hub_bikes@yahoogroups.com
                                > > Sent: Saturday, September 3, 2011 10:45 PM
                                > > Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo
                                > >
                                > >
                                > >  
                                > > I am not sure such a thing exists.
                                > >
                                > > If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors.
                                > > Hub dynamos also zoom their voltage up if you don't draw "all" of their current.
                                > >
                                > > I use a voltage doubler feeding a switching power supply, and with a modest current draw I get 20 volts at not much speed.
                                > > (The lights come on solid at 3mph).
                                > >
                                > > David
                                > >
                                > > On 2011-09-03, at 9:13 AM, thon_thon wrote:
                                > >
                                > > > i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!
                                > >
                                >
                              • Rich W
                                Per some web information I have seen in the past, under open circuit conditions at high speed the output terminal voltage on a hub dynamo can get to the 50+
                                Message 15 of 29 , Sep 4, 2011
                                • 0 Attachment
                                  Per some web information I have seen in the past, under open circuit conditions at high speed the output terminal voltage on a hub dynamo can get to the 50+ volts range, enough to give quite a shock. One reason why it is not recommended to switch on LED dynamo lighting while descending at high speeds. The initial power surge can cause component failures. Also good at blowing bulbs in the old incandescent bulb unprotected headlights.

                                  Rich Wood

                                  --- In Geared_hub_bikes@yahoogroups.com, "Paul Toigo" <ptoigo@...> wrote:
                                  >
                                  > How's your German? I interpret that the SON can output 12V at 20km/hr, but
                                  > never more than 0.5A. From Schmidt's website:
                                  >
                                  > http://www.nabendynamo.de/service/12volt/12vinfo.html
                                  >
                                  > http://www.nabendynamo.de/produkte/pdf/12vinfo.pdf
                                  >
                                  > http://www.nabendynamo.de/service/pdf/ar_11-12_2007.pdf
                                  >
                                • David Chase
                                  ... Which is why, in pursuit of thwarting the better idiot (i.e., me, and my kids) I build systems with no switch, and continuous soldered wires end-to-end.
                                  Message 16 of 29 , Sep 4, 2011
                                  • 0 Attachment
                                    On 2011-09-04, at 2:44 PM, Rich W wrote:
                                    > One reason why it is not recommended to switch on LED dynamo lighting while descending at high speeds.

                                    Which is why, in pursuit of thwarting the better idiot (i.e., me, and my kids) I build systems with no switch, and continuous soldered wires end-to-end. Bike rolls, lights go on.

                                    David
                                  • thon_thon
                                    if i use hub dynamo 6v/3w what is the maximum value of power can generate and in what speed? what would be the better output, to use the 6v/3w hub dynamo or
                                    Message 17 of 29 , Sep 5, 2011
                                    • 0 Attachment
                                      if i use hub dynamo 6v/3w what is the maximum value of power can generate and in what speed?

                                      what would be the better output, to use the 6v/3w hub dynamo or use a cheap 12v bottle dynamo?


                                      --- In Geared_hub_bikes@yahoogroups.com, "Rich W" <astronut1001@...> wrote:
                                      >
                                      > Welcome to the group.
                                      >
                                      > I do not know of a hub dynamo rated for more than 6v, 3watts but actual power output can be far more than that at higher speeds. The rated output has to do with German bicycle lighting laws and their requirements for low speed performance. Companies design to meet those laws as Germany is the largest market for dynamo lighting due to it being required on most bicycles sold there.
                                      >
                                      > Supernova makes a dynamo light set designed to take advantage of it, their triple headlight which puts out a claimed 600 Lumens but not until about 24 MPH per an email discussion I had with Supernova. It is not street legal in Germany.
                                      >
                                      > If you need a 12VDC output that has some regulation then investigate the E-Werk by Busch & Muller. It may allow you to do what you want.
                                      >
                                      > http://www.peterwhitecycles.com/ewerk.asp
                                      >
                                      > Note that the manual is downloadable from this site which covers the device capabilities in detail. Not cheap but it might solve your problem.
                                      >
                                      > Another device is the pedalpower bit it looks like it is limited to 5VDC USB charged device power output.
                                      >
                                      > http://www.peterwhitecycles.com/pedalpowerplus.asp
                                      >
                                      > Busch & Muller does make a 12V 6W bottle dynamo, a very expensive item. There are also some asian cheap bottle dynamos which claim to be 12V 6W. Per posts from one member the B&M dynamo must be mounted in a particular orientation or it is not water resistant apparently.
                                      >
                                      > Rich Wood
                                      >
                                      > --- In Geared_hub_bikes@yahoogroups.com, erickson osit <dharickson@> wrote:
                                      > >
                                      > > ah, Ok! is that the hub dynamo can only generate at 6v/3w? i think its defend on the speed, right?
                                      > >
                                      > >
                                      > > ________________________________
                                      > > From: David Chase <dr2chase@>
                                      > > To: Geared_hub_bikes@yahoogroups.com
                                      > > Sent: Saturday, September 3, 2011 10:45 PM
                                      > > Subject: Re: [Geared_hub_bikes] 12 volts hub dynamo
                                      > >
                                      > >
                                      > >  
                                      > > I am not sure such a thing exists.
                                      > >
                                      > > If DC is okay, you can build a voltage doubler with 4 diodes and 3 electrolytic capacitors.
                                      > > Hub dynamos also zoom their voltage up if you don't draw "all" of their current.
                                      > >
                                      > > I use a voltage doubler feeding a switching power supply, and with a modest current draw I get 20 volts at not much speed.
                                      > > (The lights come on solid at 3mph).
                                      > >
                                      > > David
                                      > >
                                      > > On 2011-09-03, at 9:13 AM, thon_thon wrote:
                                      > >
                                      > > > i need a hub dynamo that generate 12volts, i need it in my project! please help me, email me or contact me me in this number 09154897531! thank you very much!
                                      > >
                                      >
                                    • David Chase
                                      A hub generates more power than a sidewall dynamo. The faster you go, the higher the power. According to the data at pilom.com you maximize your power by
                                      Message 18 of 29 , Sep 5, 2011
                                      • 0 Attachment
                                        A hub generates more power than a sidewall dynamo.

                                        The faster you go, the higher the power. According to the data at pilom.com you maximize your power by pulling about 80% of rated current (e.g., 400 mA from the hub, instead of 500 mA rated). The voltage goes very high, giving you (about) MPH/2.5 watts (or KPH/4). 25mph means 10 watts. The voltage generated under these conditions (based on the pilom.com data, again) is about the same as MPH -- 25MPH means 25V.

                                        For low speed operation you can build a voltage doubler and pull half the current (200mA), but then you have to deal with high voltages at high speeds.

                                        HOWEVER -- if you are always dumping current into a battery, that will cap the voltage (by allowing more than 200mA to flow, thus quenching the dynamo). Beware of the overcharged battery; I looked into the issue for a while for my own fun, and decided that it was a pain to get right, especially on a bicycle (varying heat transport from battery because of changes in temperature and wind). The two batteries/strategies that I concluded were likely to work were:

                                        - NiMH, charged at trickle rate or below (slow charge, no possibility of overcharge)
                                        I think this works, I am not 100% sure.

                                        - Li ion, charged to no more than 80% (using voltage level to gauge charge).

                                        In both cases, you would want the batteries to be pretty close to the microprocessor that is controlling them, so that you can do sanity checks on the temperature (Atmel AVR processors have on-board temperature sensors you can read). Too hot is a red flag, and too cold is incompatible with charging some batteries.

                                        David


                                        On 2011-09-05, at 8:59 AM, thon_thon wrote:

                                        > if i use hub dynamo 6v/3w what is the maximum value of power can generate and in what speed?
                                        >
                                        > what would be the better output, to use the 6v/3w hub dynamo or use a cheap 12v bottle dynamo?
                                      • Alex Wetmore
                                        I don t think that any of the hubs have limiters in them. I know that Shimano and SON ones do not (I don t own hubs by any other companies). The lights or
                                        Message 19 of 29 , Sep 5, 2011
                                        • 0 Attachment

                                          I don't think that any of the hubs have limiters in them.  I know that Shimano and SON ones do not (I don't own hubs by any other companies).  The lights or whatever other electronics that are hooked up to the hub need to properly regulate to their needs.

                                           

                                          The original poster sounds like he was planning on using this on an electric bicycle.  I don't think that there is any benefit to running a dynohub on an electric bicycle, the power produced by the hub is tiny compared to what is carried in the batteries.  It also takes ~5W of human power to generate 3W of electrical power through the most efficient generator hubs, so running with the hub on while the motor does it's thing makes no sense (if it did make sense you'd have a perpetual motion machine).  The dynamo in the hub is not large enough to be used for anything like regen braking.

                                           

                                          alex

                                           


                                          From: Geared_hub_bikes@yahoogroups.com [Geared_hub_bikes@yahoogroups.com] on behalf of chkamb@... [chkamb@...]
                                          Sent: Sunday, September 04, 2011 4:12 AM
                                          To: Geared_hub_bikes@yahoogroups.com
                                          Subject: [Geared_hub_bikes] Re: 12 volts hub dynamo



                                          Hi, most hub dynamos deliver more than 6V and have a built in voltage limiter of some sort. If you have a hub dynamo for experiments try to run it without the limiter... SON delivers almost 12V at speeds higher that 20 km/h..
                                          Here is a German page with some insights on 12v dynamos:
                                          www.enhydralutris.de/Fahrrad/Beleuchtung/index.html
                                          There was one German dynamo (a so called spoke dynamo) with 12V that comes near to a hub dynamo: FER SD 12V. I am searching for it for years - no chance.. (Pictured here: www.pdeleuw.de/fahrrad/beleuchtung.html#dynamo "Speichendynamos").

                                          Chris

                                        • Rich W
                                          Agreed. A couple of bottle dynamos do have voltage output limiters in them, apparently intended to save halogen bulbs from being destroyed by high speed
                                          Message 20 of 29 , Sep 5, 2011
                                          • 0 Attachment
                                            Agreed. A couple of bottle dynamos do have voltage output limiters in them, apparently intended to save halogen bulbs from being destroyed by high speed operation. I know of no hub dynamo so equipped. The general philosophy today is to put the power control circuit in the headlamp.

                                            A voltage limiting zener diode circuit in the dynamo would artificially limit the power output available to the headlights which can use the extra power.

                                            --- In Geared_hub_bikes@yahoogroups.com, Alex Wetmore <alex@...> wrote:
                                            >
                                            > I don't think that any of the hubs have limiters in them. I know that Shimano and SON ones do not (I don't own hubs by any other companies). The lights or whatever other electronics that are hooked up to the hub need to properly regulate to their needs.
                                            >
                                            >
                                            >
                                            > The original poster sounds like he was planning on using this on an electric bicycle. I don't think that there is any benefit to running a dynohub on an electric bicycle, the power produced by the hub is tiny compared to what is carried in the batteries. It also takes ~5W of human power to generate 3W of electrical power through the most efficient generator hubs, so running with the hub on while the motor does it's thing makes no sense (if it did make sense you'd have a perpetual motion machine). The dynamo in the hub is not large enough to be used for anything like regen braking.
                                            >
                                            >
                                            >
                                            > alex
                                            >
                                            >
                                            >
                                            > ________________________________
                                            > From: Geared_hub_bikes@yahoogroups.com [Geared_hub_bikes@yahoogroups.com] on behalf of chkamb@... [chkamb@...]
                                            > Sent: Sunday, September 04, 2011 4:12 AM
                                            > To: Geared_hub_bikes@yahoogroups.com
                                            > Subject: [Geared_hub_bikes] Re: 12 volts hub dynamo
                                            >
                                            >
                                            >
                                            > Hi, most hub dynamos deliver more than 6V and have a built in voltage limiter of some sort. If you have a hub dynamo for experiments try to run it without the limiter... SON delivers almost 12V at speeds higher that 20 km/h..
                                            > Here is a German page with some insights on 12v dynamos:
                                            > www.enhydralutris.de/Fahrrad/Beleuchtung/index.html
                                            > There was one German dynamo (a so called spoke dynamo) with 12V that comes near to a hub dynamo: FER SD 12V. I am searching for it for years - no chance.. (Pictured here: www.pdeleuw.de/fahrrad/beleuchtung.html#dynamo "Speichendynamos").
                                            >
                                            > Chris
                                            >
                                          • Paulos, Richard G
                                            http://www.ebay.com/itm/170605907960 I ve seen these DC motor/generators used on bicycles as a generator for household electric items such as xmas lights and a
                                            Message 21 of 29 , Sep 5, 2011
                                            • 0 Attachment
                                              http://www.ebay.com/itm/170605907960

                                              I've seen these DC motor/generators used on bicycles as a generator for household electric items such as xmas lights and a boombox. That can work on items that don't depend on a fixed frequency or voltage. To get the high rpms, they used a small rubber drive wheel pressing directly on the bicycle tire tread. Seemed to put out quite a bit of juice for not a lot of pedaling effort. They are slightly larger than a 12oz soda can. A dc generator means you don't need an inverter but you would still need voltage regulation so you don't cook the batteries just like any car.

                                              A few years ago on Ragbrai, there was a prototype Pterosail (sp!). A trike of sorts with sails. They had an automotive alternator driven from the rear wheel that charged 2 full size car batteries. Plus an electric motor to drive the trike. Theory being that when the wind was blowing, they could engage the alternator to charge the batteries. I suppose they could do the same on down hills. Then on up hills, turn on the drive motor. The back up system was pedals. They spent most of their time pedaling and going v e r y s l o w l y. Their current website shows a substantially different and lighter machine.

                                              Rick (iowa)
                                            • Bruce Gilmore
                                              I have a shimano DH-S501 dynamo , its the alfine version with centrelock rotors , it has an external voltage regulator. i use an Supernova E3 triple which
                                              Message 22 of 29 , Sep 5, 2011
                                              • 0 Attachment
                                                I have a shimano DH-S501 dynamo , its the alfine version with centrelock rotors , it has an external voltage regulator. i use an Supernova E3 triple which says in the instructions to run it without any form of regulation. i'm sure i read somewhere that the top end shimano dynamo hubs were capable of 50V at 70mph

                                                http://www.rosebikes.co.uk/article/shimano-hub-dynamo-alfine-dh-s501/aid:333819

                                                --- In Geared_hub_bikes@yahoogroups.com, "Rich W" <astronut1001@...> wrote:
                                                >
                                                > Agreed. A couple of bottle dynamos do have voltage output limiters in them, apparently intended to save halogen bulbs from being destroyed by high speed operation. I know of no hub dynamo so equipped. The general philosophy today is to put the power control circuit in the headlamp.
                                                >
                                                > A voltage limiting zener diode circuit in the dynamo would artificially limit the power output available to the headlights which can use the extra power.
                                                >
                                                > --- In Geared_hub_bikes@yahoogroups.com, Alex Wetmore <alex@> wrote:
                                                > >
                                                > > I don't think that any of the hubs have limiters in them. I know that Shimano and SON ones do not (I don't own hubs by any other companies). The lights or whatever other electronics that are hooked up to the hub need to properly regulate to their needs.
                                                > >
                                                > >
                                                > >
                                                > > The original poster sounds like he was planning on using this on an electric bicycle. I don't think that there is any benefit to running a dynohub on an electric bicycle, the power produced by the hub is tiny compared to what is carried in the batteries. It also takes ~5W of human power to generate 3W of electrical power through the most efficient generator hubs, so running with the hub on while the motor does it's thing makes no sense (if it did make sense you'd have a perpetual motion machine). The dynamo in the hub is not large enough to be used for anything like regen braking.
                                                > >
                                                > >
                                                > >
                                                > > alex
                                                > >
                                                > >
                                                > >
                                                > > ________________________________
                                                > > From: Geared_hub_bikes@yahoogroups.com [Geared_hub_bikes@yahoogroups.com] on behalf of chkamb@ [chkamb@]
                                                > > Sent: Sunday, September 04, 2011 4:12 AM
                                                > > To: Geared_hub_bikes@yahoogroups.com
                                                > > Subject: [Geared_hub_bikes] Re: 12 volts hub dynamo
                                                > >
                                                > >
                                                > >
                                                > > Hi, most hub dynamos deliver more than 6V and have a built in voltage limiter of some sort. If you have a hub dynamo for experiments try to run it without the limiter... SON delivers almost 12V at speeds higher that 20 km/h..
                                                > > Here is a German page with some insights on 12v dynamos:
                                                > > www.enhydralutris.de/Fahrrad/Beleuchtung/index.html
                                                > > There was one German dynamo (a so called spoke dynamo) with 12V that comes near to a hub dynamo: FER SD 12V. I am searching for it for years - no chance.. (Pictured here: www.pdeleuw.de/fahrrad/beleuchtung.html#dynamo "Speichendynamos").
                                                > >
                                                > > Chris
                                                > >
                                                >
                                              • peluli2002
                                                Happy birthday list! ... So it is. And the relatively high voltage of an unloaded dynamo (hub or bottle) does not do any harm. Neither to people nor to
                                                Message 23 of 29 , Sep 5, 2011
                                                • 0 Attachment
                                                  Happy birthday list!

                                                  --- In Geared_hub_bikes@yahoogroups.com, "Rich W" <astronut1001@...> wrote:
                                                  >
                                                  > A couple of bottle dynamos do have voltage output limiters in them, apparently intended to save halogen bulbs from being destroyed by high speed operation. I know of no hub dynamo so equipped.

                                                  So it is. And the relatively high voltage of an unloaded dynamo (hub or bottle) does not do any harm. Neither to people nor to equipment.
                                                  (a few cases where electronic swicthes or similar could not deal with it)

                                                  What people sometimes feel is the high voltage spike wich comes from interupting the ciruit, due to the inductance.

                                                  Back to a so called 12V system:

                                                  It was quite popular here to have a second light in series, Schmidt had (has?) the E6z for this purpose. From maybe some 18km/h up it worked very well.

                                                  It is possible to get more than ~0.5A out of a dynamo, but then you have to deal with different capacitors and simlar.
                                                  10W at moderate speed is possible, but the drag is then a problem.

                                                  I was thinking about a power maximizer some time ago, but have more important projects to deal with.

                                                  There is much more to write about, and is already written down in the abovementioned website. ( http://www.enhydralutris.de )

                                                  Peter




                                                  The general philosophy today is to put the power control circuit in the headlamp.
                                                  >
                                                  > A voltage limiting zener diode circuit in the dynamo would artificially limit the power output available to the headlights which can use the extra power.
                                                  >
                                                  > --- In Geared_hub_bikes@yahoogroups.com, Alex Wetmore <alex@> wrote:
                                                  > >
                                                  > > I don't think that any of the hubs have limiters in them. I know that Shimano and SON ones do not (I don't own hubs by any other companies). The lights or whatever other electronics that are hooked up to the hub need to properly regulate to their needs.
                                                  > >
                                                  > >
                                                  > >
                                                  > > The original poster sounds like he was planning on using this on an electric bicycle. I don't think that there is any benefit to running a dynohub on an electric bicycle, the power produced by the hub is tiny compared to what is carried in the batteries. It also takes ~5W of human power to generate 3W of electrical power through the most efficient generator hubs, so running with the hub on while the motor does it's thing makes no sense (if it did make sense you'd have a perpetual motion machine). The dynamo in the hub is not large enough to be used for anything like regen braking.
                                                  > >
                                                  > >
                                                  > >
                                                  > > alex
                                                  > >
                                                  > >
                                                  > >
                                                  > > ________________________________
                                                  > > From: Geared_hub_bikes@yahoogroups.com [Geared_hub_bikes@yahoogroups.com] on behalf of chkamb@ [chkamb@]
                                                  > > Sent: Sunday, September 04, 2011 4:12 AM
                                                  > > To: Geared_hub_bikes@yahoogroups.com
                                                  > > Subject: [Geared_hub_bikes] Re: 12 volts hub dynamo
                                                  > >
                                                  > >
                                                  > >
                                                  > > Hi, most hub dynamos deliver more than 6V and have a built in voltage limiter of some sort. If you have a hub dynamo for experiments try to run it without the limiter... SON delivers almost 12V at speeds higher that 20 km/h..
                                                  > > Here is a German page with some insights on 12v dynamos:
                                                  > > www.enhydralutris.de/Fahrrad/Beleuchtung/index.html
                                                  > > There was one German dynamo (a so called spoke dynamo) with 12V that comes near to a hub dynamo: FER SD 12V. I am searching for it for years - no chance.. (Pictured here: www.pdeleuw.de/fahrrad/beleuchtung.html#dynamo "Speichendynamos").
                                                  > >
                                                  > > Chris
                                                  > >
                                                  >
                                                • thon_thon
                                                  is it posible to create a 50w power or more in a hub dynamo?
                                                  Message 24 of 29 , Sep 8, 2011
                                                  • 0 Attachment
                                                    is it posible to create a 50w power or more in a hub dynamo?

                                                    --- In Geared_hub_bikes@yahoogroups.com, David Chase <dr2chase@...> wrote:
                                                    >
                                                    > A hub generates more power than a sidewall dynamo.
                                                    >
                                                    > The faster you go, the higher the power. According to the data at pilom.com you maximize your power by pulling about 80% of rated current (e.g., 400 mA from the hub, instead of 500 mA rated). The voltage goes very high, giving you (about) MPH/2.5 watts (or KPH/4). 25mph means 10 watts. The voltage generated under these conditions (based on the pilom.com data, again) is about the same as MPH -- 25MPH means 25V.
                                                    >
                                                    > For low speed operation you can build a voltage doubler and pull half the current (200mA), but then you have to deal with high voltages at high speeds.
                                                    >
                                                    > HOWEVER -- if you are always dumping current into a battery, that will cap the voltage (by allowing more than 200mA to flow, thus quenching the dynamo). Beware of the overcharged battery; I looked into the issue for a while for my own fun, and decided that it was a pain to get right, especially on a bicycle (varying heat transport from battery because of changes in temperature and wind). The two batteries/strategies that I concluded were likely to work were:
                                                    >
                                                    > - NiMH, charged at trickle rate or below (slow charge, no possibility of overcharge)
                                                    > I think this works, I am not 100% sure.
                                                    >
                                                    > - Li ion, charged to no more than 80% (using voltage level to gauge charge).
                                                    >
                                                    > In both cases, you would want the batteries to be pretty close to the microprocessor that is controlling them, so that you can do sanity checks on the temperature (Atmel AVR processors have on-board temperature sensors you can read). Too hot is a red flag, and too cold is incompatible with charging some batteries.
                                                    >
                                                    > David
                                                    >
                                                    >
                                                    > On 2011-09-05, at 8:59 AM, thon_thon wrote:
                                                    >
                                                    > > if i use hub dynamo 6v/3w what is the maximum value of power can generate and in what speed?
                                                    > >
                                                    > > what would be the better output, to use the 6v/3w hub dynamo or use a cheap 12v bottle dynamo?
                                                    >
                                                  • thon_thon
                                                    i saw a 300 watt Bike Pedal Power Generator, a big hub dynamo. do you know what is the voltage output of that hub dynamo?
                                                    Message 25 of 29 , Sep 9, 2011
                                                    • 0 Attachment
                                                      i saw a 300 watt Bike Pedal Power Generator, a big hub dynamo.
                                                      do you know what is the voltage output of that hub dynamo?

                                                      --- In Geared_hub_bikes@yahoogroups.com, "thon_thon" <dharickson@...> wrote:
                                                      >
                                                      > is it posible to create a 50w power or more in a hub dynamo?
                                                      >
                                                      > --- In Geared_hub_bikes@yahoogroups.com, David Chase <dr2chase@> wrote:
                                                      > >
                                                      > > A hub generates more power than a sidewall dynamo.
                                                      > >
                                                      > > The faster you go, the higher the power. According to the data at pilom.com you maximize your power by pulling about 80% of rated current (e.g., 400 mA from the hub, instead of 500 mA rated). The voltage goes very high, giving you (about) MPH/2.5 watts (or KPH/4). 25mph means 10 watts. The voltage generated under these conditions (based on the pilom.com data, again) is about the same as MPH -- 25MPH means 25V.
                                                      > >
                                                      > > For low speed operation you can build a voltage doubler and pull half the current (200mA), but then you have to deal with high voltages at high speeds.
                                                      > >
                                                      > > HOWEVER -- if you are always dumping current into a battery, that will cap the voltage (by allowing more than 200mA to flow, thus quenching the dynamo). Beware of the overcharged battery; I looked into the issue for a while for my own fun, and decided that it was a pain to get right, especially on a bicycle (varying heat transport from battery because of changes in temperature and wind). The two batteries/strategies that I concluded were likely to work were:
                                                      > >
                                                      > > - NiMH, charged at trickle rate or below (slow charge, no possibility of overcharge)
                                                      > > I think this works, I am not 100% sure.
                                                      > >
                                                      > > - Li ion, charged to no more than 80% (using voltage level to gauge charge).
                                                      > >
                                                      > > In both cases, you would want the batteries to be pretty close to the microprocessor that is controlling them, so that you can do sanity checks on the temperature (Atmel AVR processors have on-board temperature sensors you can read). Too hot is a red flag, and too cold is incompatible with charging some batteries.
                                                      > >
                                                      > > David
                                                      > >
                                                      > >
                                                      > > On 2011-09-05, at 8:59 AM, thon_thon wrote:
                                                      > >
                                                      > > > if i use hub dynamo 6v/3w what is the maximum value of power can generate and in what speed?
                                                      > > >
                                                      > > > what would be the better output, to use the 6v/3w hub dynamo or use a cheap 12v bottle dynamo?
                                                      > >
                                                      >
                                                    • David Chase
                                                      ... Mostly, no. If you were to remove the 3W/6V dynamo hub from a wheel, AND contrive to run it against a tire like a sidewall dynamo, then maybe then, but
                                                      Message 26 of 29 , Sep 9, 2011
                                                      • 0 Attachment
                                                        On 2011-09-09, at 1:49 AM, thon_thon wrote:

                                                        > is it posible to create a 50w power or more in a hub dynamo?

                                                        Mostly, no. If you were to remove the 3W/6V dynamo hub from a wheel, AND contrive to run it against a tire like a sidewall dynamo, then maybe then, but the drag would be substantial, and it might also slip on the tire. The circuit handling it would definitely need to be designed to control high voltages, and you would still need to regulate the current carefully, not least because you might overheat the hub in a short circuit at those speeds (I don't know for sure, therefore, I assume it is a possibility).

                                                        They're not designed for this. You can take bike parts 2x or 3x outside their design parameters, sometimes, but 10-15x is not going to work.

                                                        David
                                                      • Rich W
                                                        Not with any bicycle hub dynamo that I am aware of. Internal impedance related to winding wire gauge and length is the final limiting factor on output I
                                                        Message 27 of 29 , Sep 9, 2011
                                                        • 0 Attachment
                                                          Not with any bicycle hub dynamo that I am aware of. Internal impedance related to winding wire gauge and length is the final limiting factor on output I believe.

                                                          With the listed efficiencies of hub dynamos I have seen mentioned, even if theoretically possible, you would need to input about 70w from the rider minimum to get 50w out. This in addition to the wattage needed to overcome normal road, terrain and wind resistance of the bike. Unless you are a very fit athlete I believe the drag would be totally unacceptable.

                                                          Riders complain about the performance losses from the drag of a sidewall dynamo already and what you are talking about would be much worse.

                                                          Rich Wood

                                                          --- In Geared_hub_bikes@yahoogroups.com, David Chase <dr2chase@...> wrote:
                                                          >
                                                          >
                                                          > On 2011-09-09, at 1:49 AM, thon_thon wrote:
                                                          >
                                                          > > is it posible to create a 50w power or more in a hub dynamo?
                                                          >
                                                          > Mostly, no. If you were to remove the 3W/6V dynamo hub from a wheel, AND contrive to run it against a tire like a sidewall dynamo, then maybe then, but the drag would be substantial, and it might also slip on the tire. The circuit handling it would definitely need to be designed to control high voltages, and you would still need to regulate the current carefully, not least because you might overheat the hub in a short circuit at those speeds (I don't know for sure, therefore, I assume it is a possibility).
                                                          >
                                                          > They're not designed for this. You can take bike parts 2x or 3x outside their design parameters, sometimes, but 10-15x is not going to work.
                                                          >
                                                          > David
                                                          >
                                                        • Rich W
                                                          I am willing to bet that 300 watts was the theoretical maximum output. The average bike rider could not generate that kind of power to run it at or near
                                                          Message 28 of 29 , Sep 9, 2011
                                                          • 0 Attachment
                                                            I am willing to bet that 300 watts was the theoretical maximum output. The average bike rider could not generate that kind of power to run it at or near maximum output for very long, particularly with the bike not moving. Rider overheating would be a major problem.

                                                            Do a Google search for "Bike pedal power generation". Lots of stuff shows up. The article linked to below discusses power outputs achieved from a NON MOVING pedal powered generator setup from a rider I would judge to be in very good physical shape. The web site also discusses building his generator.

                                                            http://www.los-gatos.ca.us/davidbu/pedgen.html

                                                            Rich Wood

                                                            --- In Geared_hub_bikes@yahoogroups.com, "thon_thon" <dharickson@...> wrote:
                                                            >
                                                            > i saw a 300 watt Bike Pedal Power Generator, a big hub dynamo.
                                                            > do you know what is the voltage output of that hub dynamo?
                                                            >
                                                            > --- In Geared_hub_bikes@yahoogroups.com, "thon_thon" <dharickson@> wrote:
                                                            > >
                                                            > > is it posible to create a 50w power or more in a hub dynamo?
                                                            > >
                                                            > > --- In Geared_hub_bikes@yahoogroups.com, David Chase <dr2chase@> wrote:
                                                            > > >
                                                            > > > A hub generates more power than a sidewall dynamo.
                                                            > > >
                                                            > > > The faster you go, the higher the power. According to the data at pilom.com you maximize your power by pulling about 80% of rated current (e.g., 400 mA from the hub, instead of 500 mA rated). The voltage goes very high, giving you (about) MPH/2.5 watts (or KPH/4). 25mph means 10 watts. The voltage generated under these conditions (based on the pilom.com data, again) is about the same as MPH -- 25MPH means 25V.
                                                            > > >
                                                            > > > For low speed operation you can build a voltage doubler and pull half the current (200mA), but then you have to deal with high voltages at high speeds.
                                                            > > >
                                                            > > > HOWEVER -- if you are always dumping current into a battery, that will cap the voltage (by allowing more than 200mA to flow, thus quenching the dynamo). Beware of the overcharged battery; I looked into the issue for a while for my own fun, and decided that it was a pain to get right, especially on a bicycle (varying heat transport from battery because of changes in temperature and wind). The two batteries/strategies that I concluded were likely to work were:
                                                            > > >
                                                            > > > - NiMH, charged at trickle rate or below (slow charge, no possibility of overcharge)
                                                            > > > I think this works, I am not 100% sure.
                                                            > > >
                                                            > > > - Li ion, charged to no more than 80% (using voltage level to gauge charge).
                                                            > > >
                                                            > > > In both cases, you would want the batteries to be pretty close to the microprocessor that is controlling them, so that you can do sanity checks on the temperature (Atmel AVR processors have on-board temperature sensors you can read). Too hot is a red flag, and too cold is incompatible with charging some batteries.
                                                            > > >
                                                            > > > David
                                                            > > >
                                                            > > >
                                                            > > > On 2011-09-05, at 8:59 AM, thon_thon wrote:
                                                            > > >
                                                            > > > > if i use hub dynamo 6v/3w what is the maximum value of power can generate and in what speed?
                                                            > > > >
                                                            > > > > what would be the better output, to use the 6v/3w hub dynamo or use a cheap 12v bottle dynamo?
                                                            > > >
                                                            > >
                                                            >
                                                          • Colin Bryant
                                                            Nobody makes a hub dynamo like that, since 50W would be about 1/3 of what the average rider can put out. You may be able to use an electric assist, in
                                                            Message 29 of 29 , Sep 9, 2011
                                                            • 0 Attachment
                                                              Nobody makes a hub dynamo like that, since 50W would be about 1/3 of what the average rider can put out.
                                                              You may be able to use an electric assist, in "generate" mode, but again, the pedalling effort would be tremendous.
                                                               
                                                              --
                                                              Colin Bryant
                                                              Vancouver, Canada

                                                              From: thon_thon <dharickson@...>
                                                              To: Geared_hub_bikes@yahoogroups.com
                                                              Sent: Thursday, September 8, 2011 10:49:01 PM
                                                              Subject: [Geared_hub_bikes] Re: 12 volts hub dynamo

                                                               
                                                              is it posible to create a 50w power or more in a hub dynamo?

                                                              --- In Geared_hub_bikes@yahoogroups.com, David Chase <dr2chase@...> wrote:
                                                              >
                                                              > A hub generates more power than a sidewall dynamo.
                                                              >
                                                              > The faster you go, the higher the power. According to the data at pilom.com you maximize your power by pulling about 80% of rated current (e.g., 400 mA from the hub, instead of 500 mA rated). The voltage goes very high, giving you (about) MPH/2.5 watts (or KPH/4). 25mph means 10 watts. The voltage generated under these conditions (based on the pilom.com data, again) is about the same as MPH -- 25MPH means 25V.
                                                              >
                                                              > For low speed operation you can build a voltage doubler and pull half the current (200mA), but then you have to deal with high voltages at high speeds.
                                                              >
                                                              > HOWEVER -- if you are always dumping current into a battery, that will cap the voltage (by allowing more than 200mA to flow, thus quenching the dynamo). Beware of the overcharged battery; I looked into the issue for a while for my own fun, and decided that it was a pain to get right, especially on a bicycle (varying heat transport from battery because of changes in temperature and wind). The two batteries/strategies that I concluded were likely to work were:
                                                              >
                                                              > - NiMH, charged at trickle rate or below (slow charge, no possibility of overcharge)
                                                              > I think this works, I am not 100% sure.
                                                              >
                                                              > - Li ion, charged to no more than 80% (using voltage level to gauge charge).
                                                              >
                                                              > In both cases, you would want the batteries to be pretty close to the microprocessor that is controlling them, so that you can do sanity checks on the temperature (Atmel AVR processors have on-board temperature sensors you can read). Too hot is a red flag, and too cold is incompatible with charging some batteries.
                                                              >
                                                              > David
                                                              >
                                                              >
                                                              > On 2011-09-05, at 8:59 AM, thon_thon wrote:
                                                              >
                                                              > > if i use hub dynamo 6v/3w what is the maximum value of power can generate and in what speed?
                                                              > >
                                                              > > what would be the better output, to use the 6v/3w hub dynamo or use a cheap 12v bottle dynamo?
                                                              >



                                                            Your message has been successfully submitted and would be delivered to recipients shortly.