16 volts is WAAAY too much! It sounds like you've got a shorted regulator that's delivering full field current and letting the stator voltage increase without limit. That situation will boil the battery dry and damage other parts if it's not corrected soon.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!