2025 Polo R line dead battery

[steven_squirrel]

Hi all,
Have a 25 Polo R Line. Was driven on a 1 hour to/1hour back commute yesterday, no issues at all. Got up this morning and went to unlock and it's totally dead. Opened it manually, key in ignition and nothing. Popped bonnet and checked battery voltage and it's only 4 voltsWhat's happened, do the batteries die literally overnight? Is it worth sticking a charger on it or do I just leave it to VW to sort out?
The only thing different "thing" was using the heated seat briefly on the way out, but this is probably just coincidence.
Any advice greatly received, thanks!

[giannis20vt]

a one-year-old battery cannot fail under normal conditions.
Either some power consumption was left on all night and drained it, or something else strange.
4 volts is a very low voltage, even if it were short-circuited it would not have such a low voltage.
I don't know if you can charge it from such a low voltage.

[steven_squirrel]

Update:
So VW tech came out, started the car with a booster pack. All the numbers on the charging & battery circuit were spot on. Ran full diagnostics, no faults. Then did an all off leak test, also ok.
No idea

[Johntheo1]

A strange one??.
Is the "all off leak" test the parasitic loss?
You can leave any of the normal users switched on manually, interior light(s) radio etc switched on and they will all be switched off after a few minutes after leaving the car, even if you left the boot lid opened, its interior light will also be switched off after a few minutes and even any display that shows a door not properly closed will also be switched off, at least they are on my 2019 Polo.