The Science of Automotive Battery Charging - And Its Future Earlier this year, we reported on CTEK's future of automotive charging where you will no...

Earlier this year, we reported on CTEK's future of automotive charging where you will no longer need leads or a physical connection to a charger. Soon, you will just park your vehicle close to the charger and it will charge the battery remotely.

CTEK is a high-end manufacturer of battery chargers and one of the companies leading the way in remote battery charging. It's also a leading supplier to OEMs around the world. So if you buy a charger from Porsche, Bentley, Ferrari, etc., chances are it's made by CTEK.

CTEK has a number of different charging technologies available on the aftermarket, and they recently shared with us some key terms for its patented 8-step charging, helping us to understand why modern chargers like theirs work so well.

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8-Step Charging

One of the reasons why CTEK's chargers work so efficiently is its 8-step charging, available on a number of its models. It's a complex, micro-processor controlled process that ensures the lead-acid battery is always at optimum charge (lithium batteries also have an 8-step process, but it’s slightly different and requires a different charger.)


This process starts when the charger is plugged in and connected to the battery. The first safeguard is that its circuitry ensures you can’t short-out the battery, nor can you connect the terminals to the wrong leads thanks to keyed connectors.

Once connected, the first step is to examine the battery performance, which will be compromised if the battery has sat for a long time. In this case, the battery plates can get sulphates on the surfaces, which seal them and prevent the battery from taking a full charge. So CTEK has technology that “knocks” on the sulphates, causing them to crack and break down. This process of desulphation is unique and it's the first step in battery optimization and charging.

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Soft Start

The charger then uses a small current to start the charging process, but it starts gradually in order to build the charge and ensure the battery is in peak condition.

Bulk Charge

It then switches to the main charging cycle, which will charge the battery up to 80 percent – this is something every charger on the market can do, except the cheaper ones can overcharge and boil the acid, causing long term damage.



Once the bulk charge is completed, the CTEK unit reduces the amps slowly but continues charging to “top it off,” ensuring it has 100 percent charge. To avoid any damages from occurring, it constantly monitors it's state.


Circuits in the charger then check the battery and will maintain the charge. If it detects that the charge has dropped, it will repeat the process again. If, after several attempts, the battery still won’t hold a charge, the CTEK charger gives a fault indication to signify that the battery is damaged beyond repair or has an internal short circuit


When a battery sits for a long time, the acid stratifies with the strong acid dropping to the bottom and water rising to the top, which can freeze in cold weather. Essentially, the acid needs “stirring” to mix the liquid and restore the acidity. Since it isn’t possible to physically shake a battery, the CTEK charger adds low current but a high voltage to create bubbles in the acid, effectively mixing it. Once mixed, the CTEK charger will recharge the battery because its capacity will have increased with the mixing.


To maintain the battery charge, the CTEK unit will provide a small load that will run interior lights if the driver opens the door, for example. It will do this for 10 days, providing power for small usage, but not enough to start the car. This was designed for boats, RVs, etc., which run some electrical circuits such as a fridge or pumps. This means that light-electrical loads can be delivered without dissipating the charge within the battery itself.

Pulse Charge

After 10 days of maintaining the charge, the CTEK charger stops topping up the battery and goes into a pulse phase where it checks the battery periodically to ensure it's maintaining its charging level.

The Science of Automotive Battery Charging - And Its Future

The Future 

During our visit, we got a glimpse into the future of battery charging. The Swedes have signed a contract with WiTricity in the US to license its magnetic resonance technology, which allows charging over distance. CTEK currently has the global license to provide battery chargers to a certain voltage in vehicle applications.

With this technology, you will no longer have to connect your vehicle to a charger. Instead, you will simply need to be in proximity to the charger, with the power being passed between a transmitter and receiver. You won’t need to be precisely positioned, either, since there is a degree of latitude in the system that can use “repeater” units to extend the distance the power can travel.

The ink is barely dry on the new contract and applications are still being examined. Initially, the cost could be relatively high, so CTEK expects to introduce the technology through specific client applications first, with industrial applications such as fork lift trucks or emergency vehicles coming next.

It's hoped that proliferation will help to reduce costs for the average consumer, allowing domestic applications to potentially reach the market within the next 2-3 years. We should also expect to see the company work with OEMs during vehicle development in order to integrate this technology into cars, allowing owners of new vehicles to not ever worry about battery condition. They would simply plug in the charger, drive into the garage and the technology will do the rest.

As we already hinted, the near-future will also see a new smartphone app. We don't have precise details at present, but expect it to allow you to monitor your battery without needing to enter the vehicle. This should be a great tool for people with a classic car, ATV, motorcycle, etc. that perhaps only come out on weekends. Nobody wants to go out to the garage, ready for a day of fun, only to discover the battery is dead. This new technology should definitely help in that regard.

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