Using the magneto to charge a battery

I have been thinking on this a while - I wonder if there's some way to use the current from the T mag to charge a 6 (or 12) volt battery?



The reason I ask is this - a battery charger takes house current (117 vac), rectifys it, regulates the voltage, and charges a battery.



From what I read, the T mag puts out 6-17 vac, at enough current to buzz the coils and run the lights.



So my question is this - why couldn't someone rectify the output of a T mag (on a separate wire from the one to the coilbox), put a regulator on it, and use it to charge, say, a 6V Storage Battery? Has anyone done or tried this? Is there something really simple here I'm missing? Why hasn't this been done before?



I had to put an electric bulb in my taillight (yeech!) and hook up a switch for a brake light (to make it OK with California) I worry the battery I'm useing it off of will die and leave me in the dark some night. Any ideas are welcome!



Thanx,

Susanne