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How does a battery work? Understanding batteries: the types and how they charge

21 January 2026

They’re silent, usually unseen and absolutely vital to modern life. Batteries start, stop, power and enable an endless list of devices and appliances. But how do they work and what do we need to do to keep them operating? 

Simply put, a battery stores chemical energy and converts it into electrical energy when you need it. This is done through a chemical reaction inside the battery that creates a discharge of ions when a load is applied, providing the power to run your appliances, from the watch on your wrist, the phone in your pocket and the vehicle you drive. 

Types of batteries 

There isn’t just one type of battery out there. The most common you’ll encounter are lead-acid batteries (often found in cars), lithium-ion batteries (popular in portable electronics), and AGM or gel batteries, among others.  

Lead acid and lithium-ion batteries both store potential energy and release it when needed, but use the different materials reflected in their names. During charging the process is reversed, creating and storing the potential energy for later use. 

Each technology has its own strengths: lead-acid batteries are reliable and robust, lithium-ion batteries are lightweight and store lots of energy, while AGM and gel types offer better resistance to vibration and deep discharges. Importantly, these different battery chemistries need different charging approaches to keep them healthy and performing at their best. 

Lead acid batteries need certain defined stages during the charging process, including an end trickle charge, whilst lithium-ion batteries require a constant current and constant voltage method.  

This is where the latest technology steps in. CTEK, the global leader in vehicle charging solutions, has just launched the CS ONE (Gen 2) battery charger, setting a new standard for smart charging. At the heart of the CS ONE (Gen 2) is CTEK’s exclusive APTO™ adaptive charging technology.  

How does APTO™ work, and why it is a game-changer for battery care 

APTO™ technology is clever enough to automatically identify the type, size and condition of your battery as soon as it’s connected. That means whether you’re charging a traditional lead-acid car battery or a modern lithium-ion pack, the CS ONE (Gen 2) instantly adapts to what your battery needs.  

There’s no fiddling with buttons or guessing settings – just connect and let the charger do the rest. This ensures that every battery gets a fully optimised charge, extending its life and maximising performance with minimal effort from you. 

The CS ONE (Gen 2) takes things even further with built-in Wi-Fi and a brand new CTEK App, offering remote access, real-time monitoring and a full charge history. Whether you’re in the garage or halfway across the world, you have total control over your battery’s health and charging status. 

Whilst it is interesting to know how a battery works, it is more important to know why and how to maintain your batteries through regular, smart charging and maintenance. With innovations such as APTO™ technology in the CS ONE (Gen 2), smart charging has never been easier or more effective, no matter what type of battery you use. 

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