Some e-car owners have recently been almost in despair because of the above error message "Replace 12V battery soon". After correctly changing the backup battery!



The 12V backup battery must be replaced every 2-3 years during the annual service, depending on the e-car manufacturer.

It is THE safety-relevant component. Assuming that at night on the motorway at speed 130 the high-voltage system would be switched off for safety reasons, the backup battery must continue to reliably supply energy to the vehicle lighting, for example!


At the latest when the error message "Check ELEC system" (=check electrical/electronic system) appears on the on-board computer display, often in combination with the red battery warning light, it is high time to think about replacing the back-up battery.


Sometimes, even after the battery has been replaced correctly, the error message: "replace 12v battery soon"? happens.

This message normally clears automatically after replacing the 12V battery, but in some cases it does not (depending on certain conditions of the vehicle). In your case, if this error does not clear itself during installation, you will need to perform a "deep reset", which resets the DC/DC converter.


The "reset" process depends on the vehicle, the aim is always to completely shut down the electric car so that the DC/DC converter resets itself and recognises the new on-board battery. Sometimes a software update is recommended by the workshop.


Banner tip: For the "reset", be sure to check the operating instructions of your electric car now or use the services of your trusted workshop right away.


PS: Some e-car importers say that these problems have to do with 12V batteries that do not meet OE standards. We are doing further research and will inform you as soon as possible.

Otherwise, the general rule is: Hands off high-voltage components and cables (recognisable by their orange colour)! This is reserved for automotive specialists with the appropriate equipment and additional qualifications (HV high-voltage training). No matter whether it is non-electrotechnical, electrotechnical work or electrotechnical work under voltage (often with nominal voltages of 288 to over 800V)!


A brief word: The on-board power supply battery is also colloquially referred to as an auxiliary, backup, support, additional or secondary battery.

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