Battery/ alternator issue.

[seanrjordan]

Hi I’ve had an issue with my mk3 Leon this week that has Broke my trust in the car.
on Tuesday I drove around 250miles home from a trip away. All was fine no lights on the dashboard or anything. I then unloaded my car and nipped to the supermarket 12 miles total probably all was well.

I got up the next morning to go to work and my car won’t start and I get the message on the mfd 12v battery low. i take an alternate mode of transport to work. When I return home I jump start the car. I check the voltages with a multimeter and it reads 14.5 volts suggesting to me the alternator is ok. Checked against a neighbours car while that was running and theirs read 14.2v. I’ve checked my cctv and it appears no lights were left on to drain the battery. i didnt have time to mess around charging so have put a new battery in and the car has been fine since.

What puzzles me is that my old battery was purchased in march 2024. is it possible the battery could have died already?

 

[RUM4MO]

A battery dying in just over a year, not typical, but what brand was that new battery bought in March 2024, also what is your typical annual mileage as many battery suppliers will reject warranty claims if the average annual mileage is less than maybe 3,000 miles.

 

[seanrjordan]

A battery dying in just over a year, not typical, but what brand was that new battery bought in March 2024, also what is your typical annual mileage as many battery suppliers will reject warranty claims if the average annual mileage is less than maybe 3,000 miles.

Was a Bosch. Annual mileage is around 7,500 a year.

 

[Walone]

Assuming you

Was a Bosch. Annual mileage is around 7,500 a year.

Assuming your car has stop/start, was the March 2024 battery AGM or EFB? For diesel cars it's usually AGM, and it needs to be coded in to the charging system so that it charges at it's best.

 

[Craig.]

Check the car for any fault codes such as no communication with generator. This will show any issues that may be existing that could cause incorrect charging etc. Best to rule out everything else before blaming the battery.

With that being said, batteries can be faulty. The trash brands like Lion arrive DOA more often than the better brands like Varta, Exide and Bosch.

Check for the manufacturing week and year marker on the battery, see how old it really is. You may have been sold a battery that is already yonks old.