SMARTPASS 120S (1058)
CTEK SMARTPASS 120S connections
Review the CTEK SMARTPASS 120S connections, setup and installation requirements. This overview does not calculate cable or protection sizes.
- Nominal voltage
- 12 V
- Compatible systems
- 12 V
Connection overview
SMARTPASS 120S connections.
See how this component fits into a system. Use the manufacturer’s installation instructions for the complete connections.
Installation notes
Before you install.
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Verified against the manufacturer's documentation (rev. D250SE / SMARTPASS 120S UK English manual; model 1058), checked 2026-10-01. Manufacturer documentation →
What is SMARTPASS managing?
The SMARTPASS 120S connects an alternator/start-battery supply to the service bank under defined operating conditions. The battery path is rated 120 A continuous; the consumer output has a separate 80 A limit. It is a battery-management connection device, not a regulated 120 A DC-DC converter.
How are the three power connections used?
Wire ALTERNATOR + to the starter side, SERVICE + to the house battery and CONSUMERS + to noncritical loads. Its small negative, ignition and temperature-sensor wires must also be fitted. The manual directs critical loads to the service battery through their own protection, so its low-voltage disconnect cannot disable them.
What protection and mounting are specified?
The cable table gives 300 A fuses and 35 mm² battery/output conductors for runs through 2 m; longer input runs need the stated 50 mm² arrangement. Those fuses accommodate transient operation and are not a claim of 300 A continuous charging. Main connections tighten to 8 Nm. Install with ventilation and the temperature probe at the service battery.
How does operation change?
With the engine stopped, consumers use the service battery. With alternator power available, source priority can power consumers while charging the bank. The consumer guard disconnects at low service voltage; automatic start assistance can temporarily join the batteries. Check the indicator pattern and matching manual before resetting a reported fault. When adding a D250SE, use the documented combined layout and verify alternator and battery current limits independently.
Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
Alternator-to-house-battery power-management unit with a 120A battery path and separate 80A consumer output. It connects batteries under defined conditions; it is not a regulated DC-DC charger. Critical loads bypass its low-voltage consumer disconnect. Small negative/ignition/sensor wires are omitted from this power-path symbol.
- Nominal voltage
- 12 V
- Compatible systems
- 12 V
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
ALTERNATOR +
positive · input
SERVICE +
positive · bidi
CONSUMERS +
positive · output
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Connection overview. This diagram explains the connection arrangement; it does not calculate cable sizes or protection for the installation. Follow the manufacturer’s complete wiring and protection instructions.
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Plan your installation with SMARTPASS 120S.
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