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Re: 12 volts hub dynamo

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  • 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 1 of 29 , Sep 5, 2011
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      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 2 of 29 , Sep 5, 2011
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        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 3 of 29 , Sep 8, 2011
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          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 4 of 29 , Sep 9, 2011
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            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 5 of 29 , Sep 9, 2011
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              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 6 of 29 , Sep 9, 2011
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                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 7 of 29 , Sep 9, 2011
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                  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 8 of 29 , Sep 9, 2011
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                    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?
                    >



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