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Dynohub + LED
hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition and ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figuring now that I definitely need a bridge rectifier and maybe some batteries as a kind of voltage sink. Can I just rig it up with about the right number of LEDs in series to accommodate the voltages which I expect to get out of it? cheers lance |
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#2
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lance house wrote in message ... hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition and ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figuring now that I definitely need a bridge rectifier and maybe some batteries as a kind of voltage sink. Can I just rig it up with about the right number of LEDs in series to accommodate the voltages which I expect to get out of it? cheers lance LEDs burn out unless current limited, usually to a max of about 30mA No need for a rectifier. LEDs are diodes, have one connected one way round and another the other way, each LED requires its own limiting resistor. Take the forward voltage of the LED and subtract it from your average DC voltage,(assume 6V) use Ohms law to obtain limiting resistor value. Trevor |
#3
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lance house wrote in message ... hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition and ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figuring now that I definitely need a bridge rectifier and maybe some batteries as a kind of voltage sink. Can I just rig it up with about the right number of LEDs in series to accommodate the voltages which I expect to get out of it? cheers lance LEDs burn out unless current limited, usually to a max of about 30mA No need for a rectifier. LEDs are diodes, have one connected one way round and another the other way, each LED requires its own limiting resistor. Take the forward voltage of the LED and subtract it from your average DC voltage,(assume 6V) use Ohms law to obtain limiting resistor value. Trevor |
#4
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lance house wrote in message ... hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition and ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figuring now that I definitely need a bridge rectifier and maybe some batteries as a kind of voltage sink. Can I just rig it up with about the right number of LEDs in series to accommodate the voltages which I expect to get out of it? cheers lance LEDs burn out unless current limited, usually to a max of about 30mA No need for a rectifier. LEDs are diodes, have one connected one way round and another the other way, each LED requires its own limiting resistor. Take the forward voltage of the LED and subtract it from your average DC voltage,(assume 6V) use Ohms law to obtain limiting resistor value. Trevor |
#5
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Trevor Wrote: lance house wrote in message ... hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition an ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figurin now that I definitely need a bridge rectifier and maybe some batteries a a kind of voltage sink. Can I just rig it up with about the righ number of LEDs in series to accommodate the voltages which I expect to ge out of it? cheers lance LEDs burn out unless current limited, usually to a max of about 30mA No need for a rectifier. LEDs are diodes, have one connected one wa round and another the other way, each LED requires its own limitin resistor. Take the forward voltage of the LED and subtract it from your averag DC voltage,(assume 6V) use Ohms law to obtain limiting resistor value. Trevor How do you know about the maiximum current unless you know the model o the LED? What are the specifications of the Dyno and LED(s) involved -- daveornee |
#6
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Trevor Wrote: lance house wrote in message ... hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition an ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figurin now that I definitely need a bridge rectifier and maybe some batteries a a kind of voltage sink. Can I just rig it up with about the righ number of LEDs in series to accommodate the voltages which I expect to ge out of it? cheers lance LEDs burn out unless current limited, usually to a max of about 30mA No need for a rectifier. LEDs are diodes, have one connected one wa round and another the other way, each LED requires its own limitin resistor. Take the forward voltage of the LED and subtract it from your averag DC voltage,(assume 6V) use Ohms law to obtain limiting resistor value. Trevor How do you know about the maiximum current unless you know the model o the LED? What are the specifications of the Dyno and LED(s) involved -- daveornee |
#7
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Trevor Wrote: lance house wrote in message ... hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition an ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figurin now that I definitely need a bridge rectifier and maybe some batteries a a kind of voltage sink. Can I just rig it up with about the righ number of LEDs in series to accommodate the voltages which I expect to ge out of it? cheers lance LEDs burn out unless current limited, usually to a max of about 30mA No need for a rectifier. LEDs are diodes, have one connected one wa round and another the other way, each LED requires its own limitin resistor. Take the forward voltage of the LED and subtract it from your averag DC voltage,(assume 6V) use Ohms law to obtain limiting resistor value. Trevor How do you know about the maiximum current unless you know the model o the LED? What are the specifications of the Dyno and LED(s) involved -- daveornee |
#8
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lance house wrote:
hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition and ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figuring now that I definitely need a bridge rectifier and maybe some batteries as a kind of voltage sink. Can I just rig it up with about the right number of LEDs in series to accommodate the voltages which I expect to get out of it? cheers lance I have my Shimano Dynamo Hub hooked up to a luxeon III led but the system is fairly complex, going through a FET rectifier (low voltage drop), a very low voltage drop regulator which can be switched out if necessary, a 700mA constant current regulator, as well as being mounted in a Energiser 6v light with rechargeable batteries which charge when the light is off. It works O.K but is overly complex when a simpler and cheaper system might have been just as good. If anyone else is interested in going this route I will be happy to share any problems/solutions I encountered |
#9
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lance house wrote:
hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition and ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figuring now that I definitely need a bridge rectifier and maybe some batteries as a kind of voltage sink. Can I just rig it up with about the right number of LEDs in series to accommodate the voltages which I expect to get out of it? cheers lance I have my Shimano Dynamo Hub hooked up to a luxeon III led but the system is fairly complex, going through a FET rectifier (low voltage drop), a very low voltage drop regulator which can be switched out if necessary, a 700mA constant current regulator, as well as being mounted in a Energiser 6v light with rechargeable batteries which charge when the light is off. It works O.K but is overly complex when a simpler and cheaper system might have been just as good. If anyone else is interested in going this route I will be happy to share any problems/solutions I encountered |
#10
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lance house wrote:
hi has anyone tried building an LED lamp to be powered by the old Sturmey-Archer Dynohub? I found one in fantastic condition and ,ahem, fried one of my LED front lights on an, ah, test ride. I'm figuring now that I definitely need a bridge rectifier and maybe some batteries as a kind of voltage sink. Can I just rig it up with about the right number of LEDs in series to accommodate the voltages which I expect to get out of it? cheers lance I have my Shimano Dynamo Hub hooked up to a luxeon III led but the system is fairly complex, going through a FET rectifier (low voltage drop), a very low voltage drop regulator which can be switched out if necessary, a 700mA constant current regulator, as well as being mounted in a Energiser 6v light with rechargeable batteries which charge when the light is off. It works O.K but is overly complex when a simpler and cheaper system might have been just as good. If anyone else is interested in going this route I will be happy to share any problems/solutions I encountered |
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