I was working yesterday and had to sit in my car waiting for someone for quite a while. I had the radio off and nothing plugged in to the USB sockets, but the 12V battery managed to drain flat and I had to call the AA out. It seems crazy to me that the system isnt designed to prevent this from happening. The AA guy says tyhey get called out to a lot of modern cars where the battery has gone flat like this.

 

Have any of you guys experienced this? Also, if the 12V battery has goner low can't it use power from the hybrid battery to help it out? The AA guy hadnt been called out to a 2023 Octavia IV before and didnt know where the 12V battery is located, and had to use the terminals under the bonnet but apparently the actual battery is in the back somewhere. I had my boot full of stuff and we couldnt locate it. Also once he had charged it a bit I wasnt sure how to get the engine to start. Had to set the minimum charge level f=of the hybrid battery high for the engine to start up.

 

I stull cant get my head around there not being a warning and automatic shutdown before the 12V battery goes flat.

3 hours ago, mccririck said:

I was working yesterday and had to sit in my car waiting for someone for quite a while. I had the radio off and nothing plugged in to the USB sockets, but the 12V battery managed to drain flat and I had to call the AA out. It seems crazy to me that the system isnt designed to prevent this from happening.

 

You failed to say for how long not whether the ignition was on, how do you think it should have prevented the discharge caused by someone remaining in the vehicle, not locking the doors thus causing several can bus nodes to remain active for him to get out and lock the vehicle or use any of the controls, switch on lights, interior lights, seat occupancy sensor, seat belt sensors etc.

 

The current draw from this on modern vehicles is way way more than old generation vehicles where you could sit in a car with the ignition off, lights off, doors unlocked and draw zero current.

 

Before anyone points it out I realise that any discharge is way more, infinitely more than zero discharge!

Edited 18 January, 20251 yr by J.R.

With a phev if you stop does the engine stop, In which case it would be possible to be parked with ignition on but turn the radio etc off and the drls would still be lit and vehicle active. People have been known to even get  out of the car and leave them like that.

 

 

 

Edited 18 January, 20251 yr by Stonekeeper

The bit about the car usually screaming at him for various reasons illustrates very well just how many Canbus modules have to remain active until after the occupants have left the vehicle and locked it.

Just now, J.R. said:

The bit about the car usually screaming at him for various reasons illustrates very well just how many Canbus modules have to remain active until after the occupants have left the vehicle and locked it.

 

it would only do the bonging if you got out though.

 

Not relevant to the op but my enyaq requires no key or pushing of a button to start. Wakes up when i sit in it and shuts down when i get out.

Yes, and surely there's more Skoda could do to make sure drivers were alerted to this happening? It seems basic to me.

 

A year ago I accidentally left the car unlocked all night and something had been running all night and run the hybrid battery right down so that it was giving a warning in the morning and took ages to charge as I drove. I cannot fathom why there isnt something that would kick in to stop this.

Edited 18 January, 20251 yr by mccririck

Keep ignition on so everything is powered by HV battery. The biggest drain is KESSY when ignition is off in my experience. Even if not sitting in the car, just walking around it a lot with the key in the pocket leads to 12V warnings when starting it up again.
The battery is in the back on the left side. It is covered by a lid in the boot floor, but you see contacts and cables going out. Though it is not supposed to be charged over there, you have terminals under the bonnet exactly for that.

11 minutes ago, Edela said:

The battery is in the back on the left side. It is covered by a lid in the boot floor, but you see contacts and cables going out. Though it is not supposed to be charged over there, you have terminals under the bonnet exactly for that.

Yeah the AA guy wanted to take a more accurate reading at the battery.

30 minutes ago, Edela said:

Keep ignition on so everything is powered by HV battery. The biggest drain is KESSY when ignition is off in my experience. Even if not sitting in the car, just walking around it a lot with the key in the pocket leads to 12V warnings when starting it up again.

 

The problem is if you accidentally leave the ignition on all night - which I did once!) it completely drains down the high voltage battery - and I dont think thjis is good for it. Why on earth does the ignition auto turn off when this looks like happening? They seem to have failed to consider these things properly.

4 hours ago, Stonekeeper said:

it would only do the bonging if you got out though.

 

 I was making the point about the modules having to be awake to monitor the inputs/events/activity that creates the audible warnings plus all the systems that could still be operated by the occupant.

 

You cant have smart vehicles making all the decisions for you (example you are sitting in the car when its shunted from behind and rolls down an embankment, should the airbags deploy or not?) if the decision making devices and the neural network connecting them is not operational and drawing current.

When I turned the ignition on when the battery was flat it kept making all sorts of bongs and bings and flashing up warnings on the dash. It wouldnt stop.

18 hours ago, mccririck said:

The problem is if you accidentally leave the ignition on all night - which I did once!) it completely drains down the high voltage battery

Not sure I understand how is this possible, unless you leave your key inside. Mine shuts down when I go away with the key in my pocket, to the point when it becomes annoying, like I want to quickly take smth from the back and everything shuts down in just like 10 seconds.

Edited 19 January, 20251 yr by Edela

3 minutes ago, Edela said:

Not sure I understand how is this possible, unless you leave your key inside. Mine shuts down when I go away with the key in my pocket, to the point when it becomes annoying, like I want to quickly take smth from the back and everything shuts down in just like 10 seconds.

I'm not sure how it happened as it was about a year ago now. But I remember going out to the car in the morning and finding it unlocked and there was a warning about the high voltage battery being very low. I cant remember now if I'd left the key in the car or not.

Edited 19 January, 20251 yr by mccririck

Sorry, Mr McCririck, I can't help, only sympathise with you. I have had four years of having to tolerate this crap. A very weak 12v battery that is likely to let me down at any time. So much so that when it is parked in my garage I always pop the bonnet so that when it doesn't start I can get in and hook up my CTEK battery conditioner without going through the farce of trying to get into the car by the official method of prising off part of the NSF door handle. Honestly, who designs these ridiculous systems? And they call it progress! I have been warned (by Skoda, no less) not to sit in the car when stationary listening to the radio as half an hour of that will flatten the 12v battery. Unbelievable! Anyway, after three Octavias since 2002 I am trading in this iV dud for a new all-electric EV from another manufacturer who, by the way, is as gobsmacked as I am about these VAG-originated faults. My final act on trade-in day will be to take the car behind the supplying dealership and give it a good BasilFawlty-style thrashing. There, I feel better already...

 

PS, the only positive I can offer is that if you haven't got one already, buy a CTEK battery conditioner. Assuming you have a garage or, at least, a drive connect it when leaving the car parked for even two days.

23 minutes ago, Sir_Ron_Norris said:

I have been warned (by Skoda, no less) not to sit in the car when stationary listening to the radio as half an hour of that will flatten the 12v battery.

Is that by Skoda UK or the Skoda dealer?

1 hour ago, Sir_Ron_Norris said:

I have been warned (by Skoda, no less) not to sit in the car when stationary listening to the radio as half an hour of that will flatten the 12v battery. Unbelievable!

They could have fixed your car instead ffs. Excessive drain of 12V is years old problem and there were solutions rolled out like 2 years ago already. After they applied fixes and changed battery on mine, I had no issues whatsoever, even though I have a habit to sit there and listen to music for hours sometimes. Before that was the same story as yours. All in all, despite cars being obviously flawed, it all comes down to a particular dealer/workshop if you'll have a good experience in the end or not.

2 hours ago, Edela said:

They could have fixed your car instead ffs. Excessive drain of 12V is years old problem and there were solutions rolled out like 2 years ago already. After they applied fixes and changed battery on mine, I had no issues whatsoever, even though I have a habit to sit there and listen to music for hours sometimes. Before that was the same story as yours. All in all, despite cars being obviously flawed, it all comes down to a particular dealer/workshop if you'll have a good experience in the end or not.

Mine is a year and 4 months old. I don't think I have the level of problem as the other guy but it does still seem to be an issue they could improve.

My car is going in next week and is booked for the whole week.

last year two flat batteries, and now 10 instances since 9/12 of the 12v battery warning.

 

11 hours ago, wantaskoda said:

"10 instances since 9/12 of the 12v battery warning" . I've stopped counting the number of times I get that warning. And that's in spite of the main charging lead being connected (and staying connected until I next need the car), or connecting the CTEK as I said earlier. Interesting to see your previous car was a 2.0 L&K. So was mine (2009) and the one before that (2002). That was when Skoda built good, reliable Octavias.

 

Edited 22 January, 20251 yr by Sir_Ron_Norris
Typo

On 21/01/2025 at 11:30, Edela said:

They could have fixed your car instead ffs. Excessive drain of 12V is years old problem and there were solutions rolled out like 2 years ago already. After they applied fixes and changed battery on mine, I had no issues whatsoever, even though I have a habit to sit there and listen to music for hours sometimes. Before that was the same story as yours. All in all, despite cars being obviously flawed, it all comes down to a particular dealer/workshop if you'll have a good experience in the end or not.

Like you, I had a new battery fitted but no improvement. What does ffs mean?

14 hours ago, Sir_Ron_Norris said:

What does ffs mean?

For F***s Sake!

On 21/01/2025 at 22:06, wantaskoda said:

My car is going in next week and is booked for the whole week.

last year two flat batteries, and now 10 instances since 9/12 of the 12v battery warning.

 

Yeah I've noticed a 12V battery warning several times in mine.

Got like 10 warning in 2 weeks. Read a lot about these issues. Car is from 2021. Bought is recently 

Car went in yesterday.

service guy seems to know what he is talking about (!!)

 

called me yesterday and he said they think an update a week or so ago had something that has sorted it.

 

(not had the error since 11/1)

 

will be getting the car back today and hopefully won’t get the message again.

 

Hello @wantaskoda,

Can you please ask the dealer for details about the software updates they performed on you car and which module has been upgraded?
I'm encountering the same issue on cold morning on first start after the car has been sitting for more that 3-4 days during the Winter period.

Thank you.
All the best,
DN
 

Edited 28 January, 20251 yr by djmartzian