Consequences of fitting the wrong battery for start-stop systems

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    Start-stop technology is a sophisticated technology, which enables cost savings for drivers and importantly environmental benefits. However, the benefits of the start-stop technology involve an increased load on the battery. Start-stop can switch off the engine at every time the car comes to a stop and start it again when the accelerator is pressed or the brake released.

    When Start- Stop is active, say waiting at traffic lights, the large number of electrical consumers still have to be supplied with electricity. The radio is on, a smartphone is being charged, and the air conditioning continuously provides the necessary cooling in the car. In spite of this, the engine must still be started by the battery when the traffic light turns green. To meet these requirements, innovative batteries have been developed especially for use in vehicles with automatic start-stop systems. The wrong battery ultimately could lead to unwished consequences.


    Consequences of using a conventional car battery

    A conventional starter battery cannot meet the demands of a vehicle with an automatic start-stop system. This is true both for cars with simple start-stop systems and EFB batteries as well as for vehicles with advanced start-stop systems. These vehicles which are equipped with recuperation, the electricity which is generated by the braking process is stored in the AGM battery.


    These are the possible consequences of using a conventional starter battery in a vehicle with start-stop:

    wrong battery - loss of warranty

    Loss of warranty

    The use of unsuitable or unapproved starter batteries in vehicles with start-stop will result in the loss of warranty. The driver or the workshop will be liable for all consequential damage and loss of function associated with the installation of an incorrect battery.






    wrong battery - failure of comfort functions

    Loss of driving comfort

    Ideally, the Battery Management System (BMS) detects the installation of an incorrect battery and adapts the start-stop system to the lower power of the battery in order to ensure that the engine continues to start. In case of doubt, comfort functions such as seat heating and other features are not available during a stop phase.

    If the battery management system does not detect the installation of an incorrect battery and does not adjust the energy management accordingly, this can result in a considerable reduction of the service life of the battery.




    wrong battery - start stop system fail

    Restricted start-stop functionality

    Due to the incorrect battery the amount of electrical energy is too low which will lead to rapid deterioration of the battery and causes the start-stop system to rarely or even never switch off the engine. This causes increased fuel consumption and greater pollution.








    wrong battery - risk of leaking acid

    Leaking battery acid

    Battery acid may leak if the battery case bursts due to overload and electrochemical processes. A sudden escape of battery acid can cause a severe risk to health.

    Use of the incorrect battery technology in a start-stop vehicle results in more rapid deterioration of the battery. Because of this, as a result of overload, in extreme cases the battery acid may also leak.





    Which is the best replacement battery?

    In Europe, there are about 30,000 different models of vehicles, so that it is impossible to know which the right replacement battery is for each of these models. The VARTA Partner Portal provides partner workshops with assistance in this decision, with battery positions, battery selections and installation instructions for almost all vehicles which are in use in Europe. For end customers, the VARTA battery search is an ideal tool to find the right battery.

    You can read more about this topic in our article on the correct replacement battery for start-stop systems.


    However, it is important to remember that an AGM must be installed wherever an AGM was originally installed! This is the only way to ensure that the vehicle functions as well as with the original component after the battery has been replaced.