Thanks Tony but I would certainly hope for greater than 12.8v maximum!! And disconnecting the green wire or any other wire from a variable voltage alternator (VVA) is not something I would suggest anyone does, VVA's on modern common rail diesel engines are ECU controlled and are part of the vehicle CANBUS...their purpose is to give manufacturers the ability to continuously adjust the output voltage to suit operating conditions at a given time. Since I initially posted my question I have found that Nissan have installed ECU VVS's on D40's and R51's since late 2011. Typical voltage will range between 12.3 and 15. Thanks