Low voltage situations & weak batteries: Bane of German cars

The car’s complex electronics go absolutely berserk due to the lack of driving, and resultant low voltage situations.

GTO recently shared this with other enthusiasts.

Short version of the story

After weeks of non / low usage of the car:

On the other hand, the minute the car got a freshly charged battery. I was so relieved as I’d thought it’s going to be a 1-lakh rupee bill!

Long version of the story

Extremely low usage of the BMW 530d due to:

  • Mumbai goes into lockdown in May 2021 (extremely low car usage).
  • Lockdown lifted, but a family member was admitted to the hospital. I was accompanying her for about 2 weeks (zero car usage).
  • I got back from the hospital and the reviews started – Octavia, Alcazar, Kushaq etc. Meaning, I was driving a lot, but only the media cars & not my own! Even otherwise, every week or two, I have a freshly launched car to test-drive (last two weeks were filled with the S-Class & Kushaq DSG) which I have to put a good number of km on for our review. To get a real feel of their behaviour, I use the media cars within the city as well as the highway. My own cars aren’t touched during these test-drive days.
  • Social outings (eating out, shopping, movies, malls etc.) have drastically reduced due to Covid. House parties are the new thing. I host a lot on my own terrace lounge, so not much driving to friends houses.
  • A contributor to my problem: I have the Varna rat repellent installed in my Bimmer & Superb, which takes up a mild amount of power, but is still a drain on the battery. Even without this device though, search online and you’ll see several owners of German cars saying they faced issues due to non-usage for 10 – 15 days (flat batteries, warning lights, error codes etc.).

Problem due to the above?

The car’s complex electronics go absolutely berserk due to the lack of driving, and resultant low voltage situations. Hooking up BMW’s scanner showed many errors, including the rear-left wheel speed sensor. Replaced the sensor, still the error code remained. All of these miraculously disappeared once the car got healthy voltage levels back.

I read somewhere about an expert mechanic claiming that 40 – 50% of the error codes on German cars today are due to low voltage, especially in this Covid work-from-home era. Today’s cars with complex electronics absolutely hate weak battery levels & low voltage for sustained periods. Forget just the high-end luxury cars, even mainstream models with many electronics like the Creta / XUV700 might face these issues.

In most cases, charging your battery (or a new battery) makes the errors go away. In severe cases, it can lead to permanent part failure. Right after the long lockdown of 2020, my ABS unit went kaput. I now firmly believe it was due to the car standing still in the lockdown months.


  • Drive them more. But it’s not always possible due to Covid, WFH, my test-driving of new cars for our reviews and the fact that I have 4 cars (so each individual car’s running is low).
  • Or get a battery charger hooked up to your parked car! I strongly recommend the Bosch C7, although there are cheaper models available too (BHPian abhi182 recently got another model for 2.5k).
  • Many enthusiasts with multiple cars in their garage have kept these car chargers / battery tenders for their rides. Several regular car + supercar + vintage car garages in India have entire fleets of 10 – 50 cars on battery tenders. I got lucky because I’m doing up my driveways this year and installed about 6 power sockets all around my compound for future EVs (my own & the test-drive cars). Little did I know that I’ll put 2 of them to use right away! I even put my toy (’97 Jeep) on a Bosch C7.
  • Other benefits = you save time (no driving around the block just to charge the battery) and your alternator will be happier too.

Fits nicely in the engine bay. This is important as my 8 parking spots are all open:

The car is now always on healthy voltage, even if I don’t start it for two weeks:

Check out BHPian comments for more insights and information.

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