I bought a second hand 2017 2.0TDI DSG Superb Estate last week.
Drives amazingly, but if I leave the doors open for maybe 15-20 minutes, no key in, the battery loses the ability to turn it over.
The battery was replaced 3 years ago by the AA when they recovered it for a fail to start breakdown - Bosch EFB 70AH.

There is something whacky with the SOS Emergency Call thing, amber triangle immediately on start up but SOS button itself shows green.
Now I also have EML amber on as well.

So a few questions:

1. Is the SOS module dragging the battery down, and can I find out if that is the case?
2. Is the EML potentially illuminated due to something unhappy with low voltage?

Sounds like the battery is failing. Do you have breakdown cover with the AA /RAC? If so they’ll come out and check it.

14 minutes ago, numskull said:

Sounds like the battery is failing. Do you have breakdown cover with the AA /RAC? If so they’ll come out and check it.

Just been poking around, it has an EFB fitted, but Google says it should be AGM?
Also there's a Halfords garage round the corner from me: https://www.halfords.com/car-repairs/car-checks/free-battery-health-check-PRODUCTBATTERY.html

Very likely that the replacement battery wasn't correctly adapted (coded into BMS) when it was replaced 3 years ago. This could possibly be a reason for premature failure of the battery, as the alternator controller may not have been allowing correct charging.

VCDS will show us everything we need to know then?

1 hour ago, RichardLarby said:

Just been poking around, it has an EFB fitted, but Google says it should be AGM?

From factory they come with EFB+ batteries.

If it's changed to AGM, then the battery type needs to b changed to "Fleece".

Also....it's 3 yrs, so it's about time to start dying, in hence time to replace.

Edited 19 hours ago19 hr by JR RS

Is it a Varta / VW EFB+.....if so, they're rubbish - my 2022 had a replacement under warranty and now that one is failing.

1 hour ago, JR RS said:

From factory they come with EFB+ batteries.

If it's changed to AGM, then the battery type needs to b changed to "Fleece".

Also....it's 3 yrs, so it's about time to start dying, in hence time to replace.

Factory fit can be either AGM or EFB - My MY16 Octavia came from the factory with an AGM - replaced, along with alternator, with a Moll EFB under warranty after 6 months.

38 minutes ago, Berisford said:

Is it a Varta / VW EFB+.....if so, they're rubbish - my 2022 had a replacement under warranty and now that one is failing.

Bosch EFB 096 70AH 650

16 hours ago, RichardLarby said:

Bosch EFB 096 70AH 650

looks like a standard EFB rather an EFB+

EFB+ models generally provide higher amp-hour capacity and slightly stronger cold-cranking amps (CCA) than baseline EFB tiers from the same brand family.