Doubt it.
The over voltage is only a VR cir issue
Have you measured the voltage to the field wire when the charging voltage is 12 to 13 and again when it is 15 to 17?
Best guess is at 15 to 17 the voltage will be close to 11 to 12v. And when charging at 12 to 14 it will be in the 6 to 9v range