Charging at 15.1 volts. Anybody?

You should do this before buying a new battery. It could be as simple as an improperly grounded VR.

Exactly. The battery has nothing to do with the problem except that it will be ruined by the high voltage. There is no regulation which does not mean the regulator is pooched necessarily. It could be connections, wiring, grounding too. I found that the electronic regulators regulated to 13.5 volts.