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Superb Charging with Added Winter Performance

The CTEK MUS 4.3 POLAR (Part No. 56-958) has been specially developed to offer excellent all-around charging with special cold weather performance and adapted AC and DC cables to handle severe cold down to -22°F (-30°C).

The MUS 4.3 POLAR is an advanced microprocessor-controlled battery charger providing unrivaled performance on batteries from 1.2Ah up to 110Ah. Features include diagnosis of battery condition to establish if it can receive and retain a charge, a patented automatic desulphation program, and a special reconditioning function that will revive and restore deeply discharged and stratified batteries. ‘Snowflake’ mode ensures ideal charging performance even in the most extreme cold conditions. Patented Float/Pulse maintenance makes the MUS 4.3 POLAR ideal for long-term storage. The entire process of battery testing, charging, and maintenance is easily followed on the clear LED display.

The MUS 4.3 POLAR is a fully automatic ‘connect and forget’ 12V charger with 8 charging steps and offers selectable 0.8A and 4.3A programs. The RECOND and SNOWFLAKE modes operate individually or together in both 0.8A and 4.3A programs, providing great flexibility for the user. The MUS 4.3 POLAR offers a wide charging range on all lead-acid battery types from 1.2Ah up to 110Ah with additional maintenance capability to 160Ah. Splash-proof and dustproof (IP65). The MUS 4.3 POLAR is easy and safe-to-use, protects vehicle electronics, is spark-free, reverse-polarity protected, and short-circuit proof. The MUS 4.3 POLAR features a 5-year warranty.


  • Complete Battery Care - Unique and patented system to recover, charge, and maintain all lead-acid battery types to maximize performance and extend life.
  • Safe and easy to use - User safety is achieved through spark-free operation and reverse polarity protection. Vehicle electrical safety is achieved through exceptionally clean voltage and current delivery with no surges or spikes. No need to disconnect the battery from the vehicle when charging.
  • Connect and Forget - Simple plug and play operation. Select the program and mode and leave the charger to do the rest.
  • Unique 8-step charging - The patented 8-step program tests battery condition and revives, charges, and maintains to ensure maximum battery life and performance. RECOND recovers deeply discharged and stratified batteries. FLOAT/PULSE maintenance ensures ideal battery care during periods of inactivity.
  • Charges down to -22°F (-30°C) - Specially developed for use in extreme cold conditions and featuring AC and DC cables adapted for low-temperature use.
  • Extends battery life - The unique features of CTEK chargers combine to maximize performance and extend battery life.

Technical Data

Part No. 56-958

  • Input voltage: 100-115 VAC
  • Charge voltage: 14.4 / 15.0 / 15.8 V
  • Charge current: Max 4.3 A
  • Type of charger: 8-step, fully automatic charging cycle
  • Type of battery: 12V lead-acid batteries (Wet, MF, AGM, GEL)
  • Battery Capacity: 1.2-110 Ah, up to 160 Ah for maintenance

“Having owned several of another ‘popular’ brand of charger, the CTEK is far and above superior in every possible category. WELL worth the miniscule additional cost. ”