Instructables

Electric bike to electric generator - Simple DIY mobile interactive science museum

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Step 2: Build Electric Light Load - Circuit design

Picture of Build Electric Light Load - Circuit design
A simple (if not precisely correct) model of the output from the DC brushless controller attached to a spinning  electric hub motor bike generator is as a 60 Volt (maximum) battery. 
(In order to hit 60 volts a rider has to use a high gear and spin very fast.) 

A nice simple online circuit simulator from Univ of Colorado is here   http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc .

Above is the circuit design for the load - 4 parallel strings with (2x 24 volt light bulbs in series).   With internal resistance each bulb is around 25 volts and the circuit is pulling ~10 amps.  Factoring in motor resistance the circuit is pulling ~600 watts.  (Considerably more than most riders can sustain.)