Model Year 21/22 Flat battery?

[Doogle]

SO….car had service yesterday no issues (apart from usual bollocks about the tyres, which are fine) drove home with no issues, this morning I get in and, battery is all but totally flat?
Neighbour ran his meter over the battery and showed only 9 Volts!
Used a power bank to jump it and it fired up right away, meter check showed voltage back up at 14 volts so appears as though starter and alternator are working which leads to possibly something causing the battery to discharge overnight or the battery itself (it’s only three years old AND on the service inspection the battery health was checked and reported as good)
Spoke to dealership and as expected they say it was only an inspection and the battery was in good health, tbf the car was fine starting at the dealership, and all the way home so I’m inclined to think something has caused the battery to drain overnight, anyone else had experience of this or similar?
Car is a 1.5dsg auto

 

[Bahnstormer_vRS]

Lights left on? Perhaps an interior light you didn't notice?

Guy

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[Doogle]

Lights left on? Perhaps an interior light you didn't notice?

Guy

Sent from my Galaxy S23 Ultra using Tapatalk

Yeah I looked at that and couldn’t see anything like, but tbh regarding say an interior light, I assume they’re LED so would draw a pretty low voltage I’d imagine, NEVER had any indication of an issue prior to this happening.
Guess I’ll have to see how it performs once charged

 

[Karbonfaiba]

While 9V overnight could be parasitic drain, it wouldn't surprise me if you actually had sudden cell failure, after they kept it on the power supply, during the service.

My own battery failed after 3 years, so I wouldn't rule out a replacement battery being required. They certainly don't make them last like they used to!

You may be able to charge it back to 12V but more importantly take a voltage reading with the ignition on. With any dead cells it won't stay above 10.5V - replacement time!

 

[Doogle]

While 9V overnight could be parasitic drain, it wouldn't surprise me if you actually had sudden cell failure, after they kept it on the power supply, during the service.

My own battery failed after 3 years, so I wouldn't rule out a replacement battery being required. They certainly don't make them last like they used to!

You may be able to charge it back to 12V but more importantly take a voltage reading with the ignition on. With any dead cells it won't stay above 10.5V - replacement time!

Cheers we trickle charged the battery for about 12-14 hours and checked the voltage which was at 13.5v BUT this was without ignition on as you suggested, it fired up straight away however, due to the battery draining, on restart the dash lit up like a damn Xmas tree and I had alerts coming out my ears, I did kind of expect this and after a short drive and a couple of “Ignition off/on” they all cleared.
I’ve been out in it today and it’s been absolutely fine, I guess time will tell, my man with the multi meter is away for the weekend but, if I have no further drain issues over the weekend I’ll have him run a test on it anyway when he gets back.
On the subject of possible causes I did have a bit of an odd thing today where (out of boredom) I actually looked at my Cupra app just to see if it showed any alerts, it said my car had a door open, I checked and they were fine, BUT the bloody lights were on, as was the ignition! Now I KNOW I turned them off, AND double checked before leaving the car, especially given the issues I’ve had, so now I’m wondering if the ignition has possibly been inadvertently turned on by myself?
It’s a mystery

 

[Bahnstormer_vRS]

It's a mystery to me, the game commences
For the usual fee plus expenses . . . . .

Guy





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[Seriously?]

It's a mystery to me, the game commences
For the usual fee plus expenses . . . . .

Guy





Sent from my Galaxy S23 Ultra using Tapatalk

And what have you got, at the end of the day...??

 

[Bahnstormer_vRS]

And what have you got, at the end of the day...??

Scarred for life, no compensation
Private investigations.

Guy

Sent from my Galaxy S23 Ultra using Tapatalk

 

[DaveSmith]

If you have a multi-meter handy. Put in on the 10A range and use the dedicated 10A socket on meter, then place it in series with the battery positive terminal and the supply to the car. So remove positive battery terminal then connect one lead to the battery positive post and the other lead to the positive cable of the car. You will now be able to see what sort of current is being drawn. Obviously do not try starting the car with the meter is series like this as the starter motor will take a lot more than 10A and will blow the fuse in the meter. However, you can turn the ignition on, then off again. Then watch as the car goes through its various sleep states. The current should get gradually less in steps as the car goes further and further to sleep over 5 minutes or so. When in the last sleep stage you'd be expecting the current draw to be less that 100ma (0.1A).

 

[Doogle]

Cheers for this

 

[serdar_18fr]

Scarred for life, no compensation
Private investigations.

Guy

Sent from my Galaxy S23 Ultra using Tapatalk

Nice to see that we also share the same musical taste, as well as cars

 

[Doogle]

Nice to see that we also share the same musical taste, as well as cars

G 'n ' R all the way (although I am also partial to Oasis as well as more traditional classic rock)