Re: Just Asking
Welcome to the forum! You will find that this is one of those questions that gets asked over and over again. I haven't seen a system posted yet that works so I suspect that it is more trouble than it's worth.
My feeling is that it would require at least a rectifier to convert the white wire output to DC voltage and a voltage regulator to keep from overcharging the battery. With the added bonus that if the battery ever starts to fail it might draw to much current and kill the engine.
My recommendation would be to get a good rechargeable battery unit and just charge it up at home when you're not riding. Of course having said that somebody will now probably come up with an ingeneous system that works!
If it can't be broken I'll find a way!
I'm not lost, I'm exploring!