CTEK Battery Chargers



CTEK was founded in 1997 and is a sister company of Creator Teknisk Utveckling AB - a leading design and development consulting firm, which was founded in 1982. CTEK began developing its battery expertise as early as 1992, when a leading battery manufacturer hired Creator for battery research and development. The company was hired to research a battery charger that would meet the charging and maintenance requirements of new generations of batteries. Unfortunatly this research and development programme ended when an American group purchased Creator's customer. Creator realised that the now patented system represented an amazing business opportunity all over the world. It was at this stage that CTEK was formed to design, develop, manufacture and market its own battery charger.

Today, CTEK has operations in the USA and China and a sales force working from Denmark, Great Britain, France, Germany and South Africa. The Head Office and development department are located in Vikmanshyttan, Dalarna, Sweden. CTEK and Creator provides employment to around 150 people.

Why choose a CTEK charger?

The rapid development of vehicle electronics has placed increasing higher demands on batteries. Modern chargers and modern charging are needed to keep up with this demand. A 3A charger of today is equivalent to a conventional 10A charger of a few years ago. CTEK's patented 8-step charging not only makes charging more efficient, but also ensures charging is carried out correctly, preventing early failure of modern batteries.

There are 3 main causes of shortened battery lifetimes:

  • Sulphating, due to undercharged batteries
  • Acid stratification: due to deeply discharged batteries
  • Drying out harmful overcharging "boils off" battery fluids

Regular care and maintenance charging of batteries, counteracts early battery failure, ensures that capacity is retained and extends the lifetime of batteries. The lifetime of a battery depends on battery type, age and condition. Taking good care of your battery can treble battery lifetimes.

The CTEK Difference

CTEK battery chargers are different. CTEK was the first company to employ "SMART" technology which uses "switched mode" electronics as found in computers, making them more flexible and accurate than linear transformers. This enables CTEK chargers to have dedicated cycles for different battery technologies and problems. This also allows the chargers to be powerful, yet small.


  1. Desulphation - Detects sulphated batteries. Pulsing current and voltage removes sulphate from the lead plates of the battery restoring the battery charging.
  2. Soft Start - Tests if the battery can accept charge. This step prevents charging proceeding with a defective battery.
  3. Bulk - Charging with maximum current until approximately 80% battery capacity.
  4. Absorption (battery ready to use) - Charging with declining current to maximise up to 100% battery capacity.
  5. Analyse - Tests if the battery can hold charge. Batteries that cannot hold charge may need to be replaced.
  6. Recond - Choose the RECOND program to add this step to the charging process. The voltage increases during this process to create controlled gassing in the battery. Gassing mixes the battery acid and returns energy to the battery.
  7. Float (fully charged) - Maintaining the battery voltage at maximum level by providing a constant voltage charge.
  8. Pulse, Maintenance Charging - Maintaining the battery at 95-100% capacity. The charger monitors the battery voltage and gives a pulse when necessary to keep the battery fully charged.

Battery Charging

As vehicle technology continues to develop, increasing strain in being placed on the battery and as a result, battery charging has become an essential part of car maintenance and should be considered as important as checking tyre pressures and oil levels.

There are various types of battery charger currently available, most predominantly smart chargers and trickle chargers. However, smart chargers present a much safer and efficient way maintaining and prolonging the life of the battery.

Once a battery has reached its optimum charge levels, a trickle charger will simply send in a level of charge for a certain amount of time and then switch itself off, continually repeating the process until it is removed from the battery. This way of battery charging can potentially over charge the battery, causing it to dry out, or even start to gas, and ultimately kill the battery.

However, CTEK’s smart chargers move into a pulse maintenance mode once the battery is fully charged. Rather than sending in a charge and estimating the batteries needs, a CTEK charger will stay in constant communication with the battery, reacting and charging only when it is needed.

In pulse maintenance mode, the battery will be allowed to naturally self discharge to a certain level before being fully charged once again. Not only does this form of battery charging avoid the risk of overcharging but, as the battery is being exercised as it be would during normal use, the lifespan of the battery is extended considerably.

Charger Functionality

The purpose of charging a battery is to regenerate the active materials sulphuric acid (H2SO4), lead(Pb) and lead oxide (PbO2) from the lead sulphate(PbSO4) formed during discharging. That's right – lead sulphate is the same material that causes the problem known as sulphating. Thus, lead sulphate is necessary in the entire process. It is when lead sulphate crystals grow large that problems arise.

A charging curve or to be more exact a charging algorithm, describes how the battery obtains its energy during the entire charging procedure. DIN standard 41773 provides guidelines for how this type of algorithm must be structured. But, most critical is knowledge of how a battery must be treated to ensure the best condition possible, aiming for the longest service life and highest capacity.

There is no universal method that solves all problems optimally. The battery itself can be manufactured a number of different ways. It is also necessary to consider the battery and the way it is used together. Because of this, the number of algorithms is huge. There is a huge difference between a modern, multistage primary switched battery charger and a linear transformer charger, which is the type found at car accessory companies and discount markets.

A couple of interesting details from the curve:

  • Even though the battery charger is marked with a high Ampere rating, this is usually measured with a battery that is down at 5-6V. A more realistic figure is 75% of the marked current strength. But, this drops quickly when the battery voltage rises.
  • The primary switch mode battery charger may lag behind at first when it comes to how much energy it provides to the battery, but it quickly catches up.
  • The linear battery charger has trouble filling the battery, even though it is at high voltage. At that point, the battery charger provides a lot more heat than current and not much more charging in the battery.
  • A battery charger that cannot provide constant voltage cannot charge the battery completely. It instead comes up to the range when the battery gases and loses fluid.
  • A rule of thumb is that 80% of charging is obtained during the first phase. All simple, regulated battery chargers go down to a lower voltage after reaching 14.4V, but it can then take weeks to obtain the final 20% of charging.

Protect your battery

To avoid the inconvenience and expense of a flat battery, it is extremely important to protect your battery. This is especially relative to vehicles that are left standing for prolonged periods of time such as seasonal motorcycles, classics cars or farm vehicles which might not be in regular use. Batteries which are standing for an extended period will inevitably slowly discharge over time which, if left untreated will eventually kill the battery.

Some tips for battery protection for vehicles that aren’t used on a regular basis.

  • When parking the vehicle for the winter/long period, the battery should be checked for any cracks and disposed of or repaired professionally if needed.
  • The top of the battery, the terminal posts and connections should be carefully cleaned with water and baking soda to remove any dirt or moisture. Dirty or moist surfaces increase the level of self discharge.
  • Contact terminals should be clean, dry and lightly greased to protect against corrosion.
  • Traditional wet / flooded batteries (not maintenance free types) should have electrolyte levels checked and topped up between min /max levels with distilled water.
  • To avoid a flat battery maintain constant regular charge. If you have electricity in your garage or storage area you can use a smart battery charger that will maintain charge levels, keep the battery in good condition and ensure that vehicle is ready as soon as it is needed.

Before re-starting the vehicle again

  • Ensure that the battery terminals are clean and secure. Check battery charge levels and recharge the battery if required.
  • It is a common misconception that a jump start, followed by a long drive fully recharges the battery from the alternator. This is not the case, as an alternator will only partly charge the battery. After this first drive, the battery will need to be charged or it will quickly be drained once again.

Battery protection needn’t be a chore, especially with a CTEK smart charger in place. All of CTEK’s chargers are fully automatic, spark proof and reverse polarity protected and require no specialist knowledge to use. A further benefit in using a CTEk charger with patented pulse maintenance technology, is that the charger can be connected to the battery for months at a time - meaning as a user, you can simply connect and forget.