Customer support


Welcome to CTEK and thank you for being a valued customer.

We are here to help and in this section you will find FAQs, troubleshooting, warranty information and video tutorials. If you can’t find what you are looking for, please contact us.

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Top 10 FAQ

  • Charger functions, Charger settings, Batteries, General, PRO25S, PRO25SE, PRO15S, CT5 POWERSPORT: Can you charge a lead acid battery with the Lithium mode?
    See answer

    No - CTEK recommend the correct charge mode be used at all times.

  • D250SE: How do I activate the Lithium setting?
    See answer

    The D250SE has a wiring harness with a black and a red wire, the black wire must be connected to battery positive (12V) to change the charging algorithm for Lithium (12V LiFePO₄) batteries.

  • D250SE: Can I use D250SE for lithium batteries?
    See answer

    Yes it works both with lead-acid and lithium (12V LiFePO₄) batteries.

  • Batteries: Can I charge Lithium batteries with a regular CTEK charger and vice versa?
    See answer

    No. Lithium batteries needs a different charge than lead/acid batteries. Due to severe risks if overcharging, we do not recommend using a CTEK charger that is developed for lead/acid batteries, for that purpose.
    Charging lead/acid batteries with a Lithium charger does not give the best result and cannot be recommended.

  • Charger functions, MXS 5.0 TEST&CHARGE: I have a CTEK charger. It used to work well, but now nothing happens when I press the mode button. I can't change between the "MC", "CAR” and "SNOWFLAKE” modes. What can I do?
    See answer

    If you can't change the charging mode by pressing the mode button regardless of which battery you are trying to charge, the charger is probably faulty. If you still have the warranty, I recommend you go to your dealer with the charger, the receipt and a completed warranty claim form.

  • CT5 TIME TO GO, CT5 TIME TO GO GULF EDITION: What is the difference between TIME TO GO and an MXS 5.0 charger?
    See answer

    TIME TO GO has a different display. Instead of the various charging steps, you see a display that counts down the time left until the battery can be used.

  • CT5 TIME TO GO, CT5 TIME TO GO GULF EDITION: I have a ride-on lawnmower. Can I use TIME TO GO to charge it?
    See answer

    Yes, you can, if you have a 12 V lead-acid battery. Note that TIME TO GO is optimized for batteries of 20 Ah upwards, so if your battery has a lower capacity than 20 Ah you should use a different charger, such as an MXS 3.8.

  • Marine, Charger functions, I1225: What is the difference between I1225 and XS25000?
    See answer

    I1225 is equipped with M10 ring terminals instead of clamps.

  • Charger functions, Batteries, PRO15S: Will my PRO15S charge lithium batteries?
    See answer

    Yes, it will charge all types of LFP / LiFePO4 Lithium Batteries when the Lithium programme is selected.

  • CTX BATTERY SENSE: How can I see more or less data in the graphs?
    See answer

    Double tap, scroll and/or pinch zoom in both graphs.

  • General: A CTEK charger is so small. How can it charge so quickly and efficiently, when compared with ordinary chargers?

    CTEK's chargers use the same type of technology that computers use to reduce dimensions, to increase power and to charge using a well controlled and 'pure' current. Also, think how big mobile telephones were 15 years ago and how small they are today, and can even so do so much more.

  • Charger functions: Absorption

    The control of gassing within the battery is very important when charging. At the end of the Bulk stage the battery is beginning to gas freely, if we were to continue with constant current and voltage the battery would gas excessively. In Absorption the voltage is now constant and the current is reduced to take the battery from 80% to 100% with minimal gassing, the CTEK charger is constantly responding to the amount of current the battery is taking and reducing accordingly.

  • Batteries: AGM

    AGM stands for Absorbed Glass Mat and differs from a standard Flooded battery in that the electrolite is held on a glass mat and pressed against the active plate area, instead of being allowed to flood around the plates. This type of battery has a low internal resistance and can accept charge very quickly making it ideal for the modern start stop systems. If the battery casing should become damaged the electrolite will not leak out.

  • Charger settings: AGM / * Snowflake

    Because the AGM battery has a low internal resistance it can accept a higher charge voltage, in this mode the Bulk charge rate is 14.7v which is the optimum chare rate for the AGM type battery. In cold weather the internal battery chemistry slows considerably, this leads to the battery being reluctant to accept charge at a normal rate. By raising the charge rate to 14.7 (15v on the Polar) the battery accepts charge more readily

  • Marine: Are the primary and secondary sides galvanically separated in your chargers?

    Yes, all CTEK chargers are galvanically separated.

  • Charger functions: Are there CTEK chargers for other battery types?

    CTEK also produces the CTEK LITHIUM XS charger, which has an ideal charging programme for 4x LiFePO4 (lithium iron phosphate) with a nominal 12V terminal voltage.
    The CTEK LITHIUM XS can also communicate with the battery's built-in electronics if the electronics have shut down the battery to protect it against deep discharging.

  • CTX BATTERY SENSE: Battery Sense Software update

    12th July Issues have been reported with the latest update on our Battery sense app – our developers are currently working hard to rectify the issue. In the mean time we have taken the decision to roll back to the previous version of the app, We have been assured this will happen over the next few days - iOS first then Android to follow.

  • Charger settings: BOOST

    This mode is used on the much larger professional units and is designed to eliminate acid stratification on larger batteries or battery banks. The voltage is increased anything up to 15.8V in 12V mode or 31.6V in 24V mode, and a timer is user selectable between 8 hrs and 24hrs.

  • Charger functions: Bulk

    A stage of intelligent charging where the battery is taken to approx 80% of full charge. This is achieved with constant current and a rising voltage. The cut off voltage can vary dependant on the type of battery being charged e.g. Flooded battery has a bulk charge voltage of 14.4v whereas the AGM has a cut off voltage of 14.7v. Note possible temperature compensation that makes the voltage vary depending on ambient temperature.

  • Batteries: CA/CA

    Calcium Calcium batteries are a flooded low maintenance or maintenance free battery usually VRLA type . During construction some of the Antimony used in the construction is replaced by Calcium (2% approx). The benefits are a more robust grid, low water loss and longer shelf life.