Common Battery Drain Issues anyone?

[fireman099]

Hi

I have a low battery on my 2017 B9, (42k) TDI. Started yesterday with the standard start stop warning (i’ve had start stop disabled to prevent battery wear for a year or so) and today won’t start and battery showing 11.5 V.
Currently got it on charge and obviously can try and new battery as guess it’s five years old now, but just wondered if anyone had any known issues with alternators or starter motors on this model? I’ve got nothing else plugged in that would drain it, only a carplay wireless dongle but that’s been in over a year?

Thanks me in advance
Neil

 

[eggraces]

Hi Neil, the battery voltage might be a red herring. I’ve found my battery voltage seems low whenever I read it with a multimeter but it seems like the power management system and the advanced alternator don’t act like an old fashioned system. Not sure what the parameters are for when the alternator clutch engages but I’ve seen my battery lower than that and I haven’t had any issues starting or errors. My car has just hit 5 years old too

 

[fireman099]

Hi Neil, the battery voltage might be a red herring. I’ve found my battery voltage seems low whenever I read it with a multimeter but it seems like the power management system and the advanced alternator don’t act like an old fashioned system. Not sure what the parameters are for when the alternator clutch engages but I’ve seen my battery lower than that and I haven’t had any issues starting or errors. My car has just hit 5 years old too

Hi, thanks for the info. Took it out for a drive and the battery voltage dropped to like 10.5 and everything started shutting down on me, so whatever it is, nothing coming out of the alternator. It’s going into a garage thursday so will see, fingers crossed.

Cheers
Neil

 

[Aldi-Sport Chap]

Hi
There is a TSB on some 2016-17 B9 Diesel batteries. It was the Molle brand. I'm not sure if it's still valid as it will be 5 years old but mine was replaced FoC at the main Stealer. I had the symptoms you describe Neil. Starts after a charge and initially ran flat over 2-3 days then overnight. Then wouldn't charge, basically I think the plates are shorting out and the electrickery safety cutout system is doing its job.