It will harm the cam sensor, and in the end the ECU, outside of the battery. Hence the first post of the thread.Bottom line, I don't think 15.1-15.5 is going to harm anything on the bike EXCEPT the battery whose life it will most certainly reduce. But why live with that risk if you don't have to?
Up to each owner to choose. Your bike and money. Pay a little now, or a lot later.