Battery Charging

Battery Charging

As vehicle technology continues to develop, increasing strain is 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 of 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 will 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 battery’s 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 would be during normal use, the lifespan of the battery is extended considerably.


Battery failure is often reported as the number one cause for breakdowns around the world. As a result, motorists are unnecessarily paying for call-out charges and more expensively, replacement batteries.

With modern vehicle full of complex and sensitive electrical equipment that constantly draw current from the battery, an ever-increasing number of mechanical faults from new and older vehicles alike are battery related. However, the expense and inconvenience of battery failure could be heavily reduced by regular battery maintenance.

CTEK’s unique range of smart chargers optimise the performance of lead-acid batteries by determining accurate readings of a battery’s charge levels and ensuring the appropriate action is taken to ensure the battery is constantly ready for use.

All CTEK chargers go through a number of stages to charge, condition and maintain the battery, extending battery’s life and, most importantly, ensuring that vehicles are able to start first time, every time and eliminating the problem of battery failure.

With each product intended for unsupervised use, foolproof to connect, spark proof and reverse polarity protected, there is no need to even disconnect the battery during use – it’s simply ‘plug and play’.


With vehicle technology developing at a pace, increasing strain is being placed on the battery just to keep the vehicle operating as it should. As a result, regular battery maintenance is more important today than it has ever been before.

Battery technology has developed hugely over the past couple of years and is continuing to do so. However, the consequence of these developments is that batteries need to be charged and maintained in a very specific way, but not all chargers are suitably adapted to do this.

Traditional battery chargers are generally unsuitable to perform battery maintenance as they treat all batteries in the same way and just provide a steady but unregulated current to the battery. This can easily lead to over, or under, charging of the battery and thereby decrease its lifespan.

Conversely, CTEK makes battery maintenance a quick, simple and extremely effective process. Its range of smart chargers constantly reads and communicates with the battery, charging only to its direct needs and therefore avoiding any possibility of incorrectly charging the battery and, but ensuring the battery is conditioned as well as charged, extending its life significantly.


Battery protection is extremely important as motorists are going to avoid the inconvenience, and expense, of a flat battery. This is especially relative to vehicles that are left standing for prolonged periods of time, such as seasonal farming vehicles, classic cars and motorcycles.

Batteries which are standing for an extended period will inevitably slowly discharge over time which, if left untreated, will eventually kill the battery.

To avoid the battery failure, CTEK has some top tips for battery protection for vehicles that aren’t used on a regular basis.

When putting the vehicle away with between seasons of over winter:

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 the vehicle is ready as soon as it is needed.

Before restarting the vehicle:

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.

Furthermore, due to the patented pulse maintenance technology, the range of chargers can be connected to the battery for months at a time meaning users can simply connect and forget.


There are a variety of car batteries currently available, Wet Cell, Calcium and AGM to name a few, each needing to be maintained in a slightly different manner but all can be dealt with with a CTEK 24V or 12V battery charger.

For car batteries, a 12V battery charger such as the MXS 5.0 will charge but also condition the battery through a series of stages that first removes the sulphur from the internal plates and then breaks it down and mixes it back into the acid solution. As a result, the battery will be given a new lease of life. For trucks and other larger vehicles, a 24V battery charger from CTEK will perform the same task.

Wet Cell, Calcium and Absorbed Glass Mat (AGM) are all various versions of the lead-acid battery that have different advantages, disadvantages and maintenance requirements.

Wet Cell car batteries, or flooded batteries as they’re also known, still dominate a large proportion of the car battery market. Despite the first wet cells typically being fragile glass containers with lead rods hanging from an open top, developments in manufacturing, and of course safety, techniques have seen the wet cell progress in to an affordable, reliable and, if recharged and maintained correctly, long lasting vehicle battery.

Calcium batteries also take up a large proportion of the battery market and have the same generic make-up of wet cell batteries except both the positive and negative plates are replaced by calcium alloy. By doing this, the fluid loss is about 80% lower than that of a normal wet cell battery and the self-discharge rate is also considerably lower which, in turn, provides huge advantages to those storing the units.

Absorbed Glass Mat (AGM) or ‘dry’ batteries as they’re also known are the latest step in the evolution of lead-acid batteries. Instead of using water or a gel, an AGM uses a fibreglass separator to hold the electrolyte in place.

GEL batteries (GEL) use a gelified acid. GEL batteries can withstand deep discharging and are for example used in vehicles with demanding electric equipment, electric wheelchairs and as consumer batteries on boats.

All of these car batteries possess different technologies that are going to suit the differing needs of the vehicle, however, they all have one thing in common in that they need to be carefully maintained to ensure once in use, they provide the energy needed. None of them are free from self-discharge and all will therefore require a charge at one point or another and a CTEK charger 24V or 12V battery charger will fulfil all of its requirements.

Unlike many battery chargers available on the market, a CTEK 24V or 12V battery charger will react only to the needs of the battery meaning that every CTEK charger is suitable to charge, condition and prolong the life of all of the above car batteries.


CTEK designs and manufactures a range of smart battery chargers and accessories to suit all types of lead-acid batteries and therefore all vehicles including cars, bikes, marine vessels, agricultural vehicles and even lawn mowers.

A CTEK smart battery charger is fully automatic, spark proof, reverse polarity protected and requires no specialist knowledge to use. Furthermore, due to the patented pulse maintenance technology, the CTEK smart battery charger range can be connected to the battery for months at a time meaning users can simply connect and forget.

All of CTEK’s smart chargers are fully automatic, spark proof, reverse polarity protected and require no specialist knowledge to use. Furthermore, due to the patented pulse maintenance technology, the range of chargers can be connected to the battery for months at a time meaning users can simply connect and forget.

A CTEK smart battery charger will undergo a series of stages during the charging process to disulphate, revive, charge, condition and maintain all types of lead-acid batteries, prolong their life and save the user time and money in the future.

Furthermore, a smart battery charger will stay in constant communication with the battery throughout the procedure, charging only to meet the needs of the battery and therefore eradicating the possibility of over-charging or under-charging the battery and reducing its lifespan as a result.

Moreover, each CTEK smart battery charger regulates mains voltage to protect any sensitive electrical and hi-fi equipment.


Unfortunately, not all electric mains provide constant 230V voltage. Even minor variations from the mains can cause the battery to be undercharged or to gas (boil). With undercharging, the negative plate is not fully converted and thus some of the material will be inactive. With overcharging, the battery boils, causing it to dry out. In addition, the heat generation destroys the lead plates.

CTEK’s primary switch mode battery charger is not affected by variations in the mains voltage, enabling it to charge the battery effectively.


Charging is intended 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 a charging algorithm to be more exact) 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 5-6 V. 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 a 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.


CTEK SWEDEN AB develops and manufactures battery chargers for all types of lead-acid batteries for both private and professional use. CTEK’s unparalleled innovation has enabled it to develop cutting-edge technology with several patented functions and properties that make CTEK battery chargers and accessories unique.

CTEK offers the market high-quality, reliable chargers and accessories that are effective, user friendly and, most importantly, safe (for the user, the vehicle electronics, the battery and the charger).

About 400 million lead-acid batteries are manufactured around the world each year. Each one requires charging. If each battery receives proper care and charging, battery life is significantly extended (about 2-3 times longer than a battery that does not receive regular care and charging).

This leads to greater protection of the environment, clear financial savings and greater vehicle reliability.

Environment: Great savings in the raw material lead (approx 7kg lead/car battery), which is in short supply, and great cutbacks in heavy transports factory-warehouse-dealer-retailer.

Economy: Investing in a charger saves on both unnecessary and early battery purchases, service vehicles and any transport expenses to solve an unnecessary problem.

Reliability: If you care for the battery properly, you avoid inconvenient surprises with ‘dead batteries’, which often happen at the worst possible time.

Since its founding, CTEK has sold about 4 million battery chargers in 60 countries around the world. CTEK is a reliable supplier to many of the world’s most respected car and motorcycle manufactures. CTEK has won more than 15 different independent battery charger tests since 2005.