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CTEK Smartpass 120

CTEK Smartpass 120

SMARTPASS 120 (Part #40-185) is a fully automatic 120A power management system that prioritizes, controls, and maximizes energy from your alternator to power your service battery. It safely separates your starter and service batteries automatically. It also distributes power between the starter battery, the service battery, and onboard equipment without the need for traditional diodes or VSR relays. This means that SMARTPASS 120 can make sure that critical functions like starters, radios, emergency lights, and communication systems always have the power they need, and take priority over noncritical functions. SMARTPASS 120 works with any 12V lead-acid battery. It can also be used with the CTEK D250SA 20A onboard charger for the ultimate 140A power management system. Comes with a 2-year warranty.


  • Fast charging – even on short journeys – using 120A current from the alternator
  • Starts the engine from the service battery when your starter battery is flat
  • Prioritizes critical functions so they’re always powered up and working when you need them
  • Automatic energy management in a single, easy to use unit – no need for traditional diodes or VSR relays
  • High-temperature protection for added safety


  • Input: 11.5–23V, Max 120A (350A temporarily for 10 seconds)
  • Output: Max. 14.4V, 120A (350A temporarily for 10 seconds)
  • Back current drain: Less than 7Ah/month
  • Ambient temperature: -20°C to +50°C (-4°F to +122°F)
  • Battery types: All types of 12V lead-acid batteries (WET, EFB, Ca/Ca, MF, AGM, and GEL)
  • Battery capacity: 28–800Ah
  • Dimensions: 192 x 110 x 65mm (L x W x H)