CTEK SmartPass 120S w/Installation Kit12V Power management system for starter and service batteries Smartpass 120S is a 120A Power Management Solution which distributes, controls and maximizes the available energy from your alternator to power service batteries and consumers. SMARTPASS 120S handles all 12V batteries between 28 800Ah. The Smartpass 120Ss Battery Guard function ensures that critical equipment such as radio, emergency lights and navigation systems always have power and take