Basslink keeps cutting off into protection!!

My basslink ii was recently installed into my 01 BMW 3 series. It works well once the car is off and works sporadically when the vehicle is running. (My power is ok and the install was done professionally). I noticed that is thumps and works well while the car is off since my battery is putting out EXACTLY 12 volts. The minute i start the car and the alternator is putting out 14 volts the basslink cuts off. I think this voltage is too high. Once I connect it to a batteyr only then it runs all day long perfectly? How can i regulate tis voltage or get bassink to accept the higher voltage without turning off?