Sustainable Energy – kinetics

Using this circuit I’m trying to light up an LED by spinning the wheel on my car – HOWEVER, it’s not working. I think I might be doing something wrong with the four diodes I’m using to try to make a full – wave rectifier. I shall later use a multimeter to see where I’m going wrong (as well as calculate the amperage and voltage I’m generating from spinning the wheel)…as well as try it with a single diode as a half-wave rectifier.