It monitors how much curt is actually being pulled from the battery in any given time and that's going to be different based on whether the ACS running whether the radiator fans running all different you know scenarios and based ondifferent factors like that it'll use the battery sensor to decide whatvoltage the alternator is going to charge at okay so if you're driving less current it's gonna charge a slightly lower voltage a lot more currents cancharge the higher voltage to make surethat it can recharge the battery as it's being depleted