I have a Shimano DH-2N01, which is listed by Shimano as putting out 2.4 watts with 6 volts, so presumably .4 amps, but my understanding is these hubs are constant current, not constant voltage. So couldn't this hub generate more than 6 volts and 2.4 watts? Do these hubs have built-in voltage regulators?

My biggest questions are regarding the circuit components: What voltage regulator, LED driver, and rectifier should I use? I want to connect three 6 volt CREE LEDs in series. Most seem to put out about 125-175 lumens at .4 amps, so I would like to use 3 for about ~400-500 lumens combined. Does anyone have any other specific LEDs they recommend for this?

I'm new to electronics projects, but I have built simple 9V tail lights and a welder from two microwave transformers, so I'm not a complete idiot about this stuff. I just can't seem to find a comprehensive article that explains the requirements for using an AC generator to power DC-driven LEDs.

Thanks in advance!