Installation Guide for CTEK Smartpass 120S Power Management System

Quick guide from the manual

The CTEK Smartpass 120S is a 120 A power management system designed to distribute, control, and maximize energy from an alternator to service batteries and consumers. It is specifically engineered to separate critical equipment from non-critical equipment, ensuring that essential systems like radio, emergency lights, and navigation always have power.

Key features and operation

• Battery prioritization: The unit automatically prioritizes critical consumers and supplies them directly from the alternator.
• Battery Guard: Protects the service battery from total discharge by disconnecting non-critical consumers when the service battery voltage is low.
• Smart alternator compatibility: Designed to work efficiently with modern smart alternators.
• Automatic operation: The system is fully automatic and eliminates the need for traditional diodes and VSR relays.
• Start assistance: Includes a start assistance function.

Compatibility and technical specifications

The Smartpass 120S is compatible with all 12 V batteries between 28–800 Ah. It is designed to work in conjunction with the CTEK D250SA and D250SE 20 A on-board chargers to create a comprehensive 140 A power management solution.

Safety and protection

• Over-temperature protection: Built-in protection reduces the charge current before the battery temperature becomes too high.
• Dynamic over-current protection: Handles temporary inputs and outputs of up to 350 A for fast charging.
• Environmental protection: The unit is splash and dust proof with an IP65 rating.