what you have is called permanent magnet alternator it will only put out about 12.5 volts tops only used to start and possibly run lights on the back side alternator is there any wires if not you have an external regulator/rectifier most of them are mounted under dash area and will have possibly 5 6 7 wires this can be bought off internet should be about $30 to $60 dollars this is the most common problem with charging system the alternator does go bad only part replaceable that i know of is the bearings repost what you find