highlander9
Newly Enlightened
- Joined
- Apr 23, 2011
- Messages
- 15
The preliminary graph of power vs speed with load of 190mA, which Martin says gives the maximum wattage. I extrapolated 17 watts for going at a speed of 65kph.
The actual power curves. This was where I started getting confused. I tried to make the 17 Watt power criteria, but couldn't really execute the graphs properly...
I was trying to do some data extrapolation from Martin's power charts. I wanted to figure out how many LEDs I would need to fully load the circuit for a lighting system which is driven by a dynohub going 65kph (or 40mph). I need to set this as my top speed, because that's the fastest my motorized bicycle travels. I do not possess any y(x) functions to make accurate extrapolations of the graphs, but I tried my best to eyeball it. I came up with a minimum of 10 LEDS, where the switch happens around 42.5kph. The brown are the bridge rectifier graphs and the peach lines represent the voltage doubler graphs. They both end at a point (blue for the voltage doubler and red for the bridge rectifier) that represent their maximums. Can somebody help verify that this extrapolated data is somewhat or close to being correct?
Is there any other way I can figure out component values for my application? such as the quantity of LEDs, capacitor values, resistor values, and for all the other components? I am going to use a Sturmey-Archer xl-fdd dyno/drum hub on a 26" wheel.
I'm also a bit concerned that I extrapolated the data where it would require 10 LEDs to fully load the system. That just seems to be too much for bicycle lighting--unless I divide them amongst a head light, tail light, and standing light (that would require more circuitry). Isn't there a way I could just use at most 6 LEDs, and just use some kind of resistor in the input of the rectifier/doubler circuit that would shunt excess voltage (from the dynamo's ac power source) as heat? It's not efficient, but I think it might be a more practical solution, don't you think? Would appreciate your help very much! Thanks!
The actual power curves. This was where I started getting confused. I tried to make the 17 Watt power criteria, but couldn't really execute the graphs properly...
I was trying to do some data extrapolation from Martin's power charts. I wanted to figure out how many LEDs I would need to fully load the circuit for a lighting system which is driven by a dynohub going 65kph (or 40mph). I need to set this as my top speed, because that's the fastest my motorized bicycle travels. I do not possess any y(x) functions to make accurate extrapolations of the graphs, but I tried my best to eyeball it. I came up with a minimum of 10 LEDS, where the switch happens around 42.5kph. The brown are the bridge rectifier graphs and the peach lines represent the voltage doubler graphs. They both end at a point (blue for the voltage doubler and red for the bridge rectifier) that represent their maximums. Can somebody help verify that this extrapolated data is somewhat or close to being correct?
Is there any other way I can figure out component values for my application? such as the quantity of LEDs, capacitor values, resistor values, and for all the other components? I am going to use a Sturmey-Archer xl-fdd dyno/drum hub on a 26" wheel.
I'm also a bit concerned that I extrapolated the data where it would require 10 LEDs to fully load the system. That just seems to be too much for bicycle lighting--unless I divide them amongst a head light, tail light, and standing light (that would require more circuitry). Isn't there a way I could just use at most 6 LEDs, and just use some kind of resistor in the input of the rectifier/doubler circuit that would shunt excess voltage (from the dynamo's ac power source) as heat? It's not efficient, but I think it might be a more practical solution, don't you think? Would appreciate your help very much! Thanks!
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