I am a little confused which is not that hard to do.. I am buying a bmv700 battery monitor that comes with a 500 amp shunt. My battery bank has a total of approx 665 amps..do I need the 1000amp shunt??the manual says that the 500 amp shunt is satisfactory in most cases. So do you base the shunt size on battery total capacity or what you expect the total maximum amp draw will be at any one time. I would expect that my max draw would not exceed 400 amps and then only when the 2000 watt inverter and bow thruster operating at the same time and then only got a couple of seconds at a time. Thanks