Take care of your battery - so that you can always (re)start.
If the battery fails due to wear or low temperatures, the only option left is to start the engine using a jumper cable or to push-start the vehicle. On the one hand, this is annoying, and on the other, it can lead to problems or even damage in many modern vehicles.
This makes it all the more important to ensure that the starter battery is in good working order and to replace it if it no longer provides sufficient electrical power.
Why combustion engines need batteries to start
At first glance, it is not obvious why combustion engines need electrical energy from a battery. Internal combustion engines are powered by fuel such as gasoline or diesel. The fuel is converted into a gas mixture and exploded in the explosion chambers of the engines (cylinders). The explosion converts the chemical energy stored in the fuel into kinetic energy. Mechanical energy must be applied to trigger an initial explosion through an intake and compression process. Only after the first explosion processes have taken place can the engine keep itself running.
At the beginning of the automobile age, a manually moved crank provided the mechanical energy to start the engine. Cranking the engine was strenuous, time-consuming and sometimes dangerous. For this reason, car manufacturers developed the so-called starter motor. This is a powerful electric motor that takes over the task of "cranking" the engine. The starter motor itself requires electrical energy to generate the mechanical power. This energy is supplied by the starter battery. The starter batteries are not actually batteries, but rechargeable batteries. Once the engine has started, the alternator recharges the battery. This ensures that sufficient power is stored in the battery to restart the engine.
Starter batteries must have these characteristics
Depending on the type, the starter motor requires a certain voltage. Typical voltages for starter batteries are 6V, 12V and 24V. Starter motors in cars are usually supplied by 12-volt starter batteries. In trucks, agricultural machinery and other very powerful vehicles, 24V systems are common. Some older motorcycles, scooters or small engines are equipped with 6V starter batteries. In order to generate enough power to crank the engine, high currents are required for a short period of time. Depending on the engine, this can be several hundred amps. The larger the engine, the higher the current to be supplied by the battery. The battery voltage must not drop during the starting process. A healthy battery should keep the electrical voltage as constant as possible during the entire starting process.
Another important characteristic of starter batteries is their cycle stability. Even after many starting processes, the electrical performance of the battery should only weaken minimally. Special features in modern vehicles, such as the automatic start/stop system, place higher demands on the cycle stability of starter batteries. High-quality batteries such as AGM or EFB batteries are optimized for cycle stability.
Low temperatures in winter also place special demands on starter batteries. In general, the internal resistance of the batteries increases with decreasing temperatures and the performance decreases. Nevertheless, the starter batteries must provide sufficient power to start the engine at sub-zero temperatures. For this reason, starter batteries have a very low internal electrical resistance, which is not overly affected by low temperatures.
Starter batteries in vehicles also have the task of supplying electrical consumers with power when the engine is at a standstill or when the alternator is producing little power due to low engine speed. This is the case, for example, when listening to music on the car radio with the engine switched off. As the electrical equipment of vehicles is becoming increasingly complex and extensive, the energy supply from the starter battery is becoming more and more important.
The different technologies for starter batteries
Starter batteries are available in various designs with different technologies. The most commonly used technologies for starter batteries are as follows:
- Wet batteries with liquid electrolyte
- Batteries with gel-like electrolyte
- AGM batteries (Absorbent Glass Mat Batteries)
- EFB batteries (Enhanced Flooded Batteries)
Most starter batteries are maintenance-free wet batteries with liquid electrolyte. These consist of individual cells, each with several positively charged (anode) and negatively charged lead grids (cathode). The anodes and cathodes are immersed in diluted sulphuric acid (electrolyte). This creates a galvanic cell with a voltage potential of around two volts. If several of these cells are connected in series, the desired voltage of six, twelve or 24 volts can be achieved. An electrical consumer such as the starter motor, which is connected to the differently charged electrodes, closes the circuit and discharges the battery. If an electric generator (alternator) is connected to the anode and cathode, the battery charges. Maintenance-free batteries are sealed and have such a low water consumption of the electrolyte that topping up with distilled water is not necessary.
A special type of starter battery is the so-called gel battery. It basically has a similar structure to a wet battery with several galvanic cells of two volts each connected in series, but uses a gel-like electrolyte rather than liquid sulphuric acid. This is achieved by adding silicic acid to the liquid sulphuric acid. Gel batteries are completely sealed and cannot be topped up with water. One advantage of these batteries is the reduced acid stratification. Acid stratification causes a loss of performance due to the electrolyte segregating into acids of different densities at different points in the galvanic cell. Compared to wet batteries, the internal resistance of gel lead-acid batteries is higher. They therefore deliver a lower maximum current. Due to their closed design and lower maximum current, gel batteries are often used in motorcycles and scooters.
High-quality vehicles with complex electrical equipment and features such as start/stop functions have an increased current requirement and require a high cycle stability of the starter battery. So-called AGM batteries (Absorbent Glass Mat Battery) are often installed in these vehicles. They have a high cycle stability for many discharges and charges and a low internal resistance for high starting currents even at low temperatures. In AGM batteries, the liquid sulphuric acid is stored in a glass fiber fleece. AGM batteries are not installed in warm engine compartments, as higher temperatures are harmful to the batteries and cause them to wear out more quickly.
EFB starter batteries are wet batteries which, in contrast to conventional lead-acid batteries, are equipped with a polyester scrim. This fabric is located on the anode plate and ensures that the active material (lead dioxide) is better fixed. The EFB starter batteries have a low internal resistance for fast charging and discharging. The cycle stability and service life of the battery is increased by 50 to 100 percent. This is reflected in the higher price compared to wet batteries.
The right starter batteries for cars, trucks and motorcycles or other vehicles and devices
The batteries and technologies used are tailored to the different types of combustion engines in cars, trucks, motorcycles or other vehicles and devices. An important criterion when purchasing is the voltage of the battery and its capacity. The batteries also differ in the arrangement, shape and size of the positive and negative terminals. The electrical data and battery technologies specified by the manufacturer must always be adhered to.
Are starter batteries suitable as supply batteries in a caravan, for example?
An important secondary function of starter batteries is to supply electrical consumers via the vehicle electrical system, for example when the engine is switched off or when the alternator speed is too low. Owners of caravans or motorhomes often ask themselves whether starter batteries can be used purely for supply purposes. This is not advisable, as the batteries with their specific lead grid structure are optimized for high starting currents and wear out more quickly than pure supply batteries. As a result, starter batteries that are used as supply batteries in a motorhome, for example, lose performance more quickly and need to be replaced in shorter periods of time.
What you should consider when buying the right starter battery
To help you select the right starter batteries for your vehicle type, our store offers a variety of practical help and filter functions. Our battery finder is very useful. All you need to do is enter a few details about your vehicle, such as manufacturer, vehicle type and type of engine. The right battery type is quickly found and you get an overview of the various performance data and prices of the batteries. To be on the safe side, compare the dimensions, capacity and battery technology with your current vehicle battery before purchasing the battery to prevent problems during installation and commissioning.
If you have any problems or questions when selecting a battery, please do not hesitate to contact our competent and friendly customer service team. They will be happy to answer your questions in detail and help you find the right battery. If you would like to buy a starter battery, the online store offers a huge selection of high-quality products from well-known manufacturers such as Banner, Bosch, Exide, Varta, Optima, Voltic, Intact and many more.
Advantages of buying starter batteries at voltimax.de
You can buy your starter battery at voltimax.de, the expert store, with many advantages. Voltimax.de offers a wide range of different starter batteries at low prices. We only sell original new products of high quality. The range of products covers all requirements. The right battery is available for every vehicle. Depending on the payment method selected, the battery will be packed and sent to you on the same day you place your order. For bargain hunters, we regularly have heavily discounted batteries available for you in our sale.





























