Just got a new mk 4.5 a few days ago. Whilst I’ve been sitting in the car trying to figure the infotainment I keep getting the following warning: “12 V battery is being discharged. Please start the engine.”

The warning displays pretty quickly, within a few minutes of entering the vehicle.

I can’t find anything in the manual about the battery with this wording so I’m unsure if this is just some general advice or if the warning implies I’ve got a dud battery from the factory.

Any ideas?

I'm guessing that, as you suspect, it's general advice. Perhaps an over-dramatic warning that without the engine running, the battery will eventually go flat.

Certainly hope so. Hopefully others can chime in with whether it pops up frequently for them or not.

Just joined...and just picked up my MK4 Estate yesterday...I drove away from the dealer and pulled into a layby to try and figure out all the wizardy of the display etc and like you up pops the warning. I put it down to the car having been sat at the dealer for about 4 months. Got home (circa 20 miles) and had another go at working out what everything does and didn't get any warning so hopefully it just needed a bit of a run to charge up.

Glad you’re not seeing this anymore. Unfortunately I’ve had a good number of 40-50 minute drives over the past few days and it still seems to pop up within minutes of the car being on without the engine also being on.

I spend a lot of time sat in car with ignition on(taxi driver) I have never had this warning.

On 20/09/2025 at 10:34, lurking said:

Glad you’re not seeing this anymore. Unfortunately I’ve had a good number of 40-50 minute drives over the past few days and it still seems to pop up within minutes of the car being on without the engine also being on.

Suggest getting the battery tested.

Does the stop start system work? Mine didn’t and it got a new battery recently after 6 months and 4,000km

32 minutes ago, whippersnapper said:

Does the stop start system work? Mine didn’t and it got a new battery recently after 6 months and 4,000km

Very random it's going to dealer on Friday for a diagnostic and infotainment update as have a lot of communication problems between the modules.

I will probably get the battery checked at some point soon. I’ve had the car for just over a month now and this still appears within minutes of being in the car with the ignition on but engine off. I will say though that no functionality seems to be effected. I’ve read that to conserve battery when it’s draining quickly the car will disable things like the radio etc. I’m not seeing anything like that happen.

12 hours ago, whippersnapper said:

Does the stop start system work? Mine didn’t and it got a new battery recently after 6 months and 4,000km

Yes, although how consistently I don’t know since I virtually always turn it off as soon as I get in the car.

2 hours ago, lurking said:

Yes, although how consistently I don’t know since I virtually always turn it off as soon as I get in the car.

Try not doing that and see. Mine would go days or weeks without turning off. Now it does it so often,like you, I end up turning it off

14 hours ago, lurking said:

Yes, although how consistently I don’t know since I virtually always turn it off as soon as I get in the car.

The Stop/Start logic is a bit illogical IMO, mine (2019 Polo) has never failed to operate even with a nearly 7 year old battery at 70% SOC, like just now, only indication I get of a low SOC is that the battery charges at well over 14V constantly, not sure what SOC when reverts to "normal" charging, ie, only 14.6/14.8V on the overrun. Set of VCDS readings taken just now.

Mileage: 37935kMs = 23,573 miles

12:34:12 20102025

  IDE01829   Generator exciter current 2.125 A

  IDE01834   Battery voltage 14.598 V (Engine Idling)

  IDE01836   Battery current 3.024 A

  IDE01837   Temperature of battery sensor 26 °C

  IDE01839   Battery charge level 70 %

  IDE01841   Battery internal resistance 7.8 mOhm

  IDE01842   Usable battery charge 23 Ah

  IDE01843   Battery voltage at rest 12.4 V

  IDE01948   Battery internal resistance not normed 8.2 mOhm

  IDE07681-MAS06086   Battery total charging throughput-Total re-charge 3478.6 Ah

  IDE07681-MAS06087   Battery total charging throughput-Entire energy throughput 3669.3 Ah

Edited 20 October, 202520 Oct by Johngerard

My skoda mk3 2015 start stop never fails 255000 miles

12 hours ago, whippersnapper said:

Try not doing that and see. Mine would go days or weeks without turning off. Now it does it so often,like you, I end up turning it off

Been out an about today. Two 40 minute drives and a handful of runs. Start stop hasn’t kicked in once.

Turned the car on there and got the battery warning within 30 seconds.

So yeah, it needs replaced.

2 hours ago, lurking said:

Been out an about today. Two 40 minute drives and a handful of runs. Start stop hasn’t kicked in once.

Turned the car on there and got the battery warning within 30 seconds.

So yeah, it needs replaced.

Its under warranty? but would be interesting if you have a multimeter and see what the battery terminal voltage is while idling.

5 hours ago, lurking said:

Been out an about today. Two 40 minute drives and a handful of runs. Start stop hasn’t kicked in once.

Turned the car on there and got the battery warning within 30 seconds.

So yeah, it needs replaced.

There you go then. On mine once I drove to the gym, stopped the engine but a podcast was still running and within 30 seconds or so it shut the car off saying it needed to preserve battery. Also got a few random ADAS and such error lights that would come on and then go off within a few miles. All clues to low battery voltage.

9 hours ago, Johngerard said:

The Stop/Start logic is a bit illogical IMO, mine (2019 Polo) has never failed to operate even with a nearly 7 year old battery at 70% SOC, like just now, only indication I get of a low SOC is that the battery charges at well over 14V constantly, not sure what SOC when reverts to "normal" charging, ie, only 14.6/14.8V on the overrun. Set of VCDS readings taken just now.

Mileage: 37935kMs = 23,573 miles

12:34:12 20102025

  IDE01829   Generator exciter current 2.125 A

  IDE01834   Battery voltage 14.598 V (Engine Idling)

  IDE01836   Battery current 3.024 A

  IDE01837   Temperature of battery sensor 26 °C

  IDE01839   Battery charge level 70 %

  IDE01841   Battery internal resistance 7.8 mOhm

  IDE01842   Usable battery charge 23 Ah

  IDE01843   Battery voltage at rest 12.4 V

  IDE01948   Battery internal resistance not normed 8.2 mOhm

  IDE07681-MAS06086   Battery total charging throughput-Total re-charge 3478.6 Ah

  IDE07681-MAS06087   Battery total charging throughput-Entire energy throughput 3669.3 Ah

My car is only 18 months old and has an entire energy throughput 8400 ah, not sure if that’s high?

Your battery resistance is quite high if you have an EFB or AGM.

Your entire energy input compared with mine, pro rata, might seem high but I dont have AC so once the engine is running and even at idling with HRS + dipped beam + fan on speed2 will not drawdown anything from the battery, the Alternator will supply all + ~ 2.A charging current. Polo has 23,573 miles up, all short runs, say 30MPH average gives engine running time of 786 hours add 25% for stopped in traffic gives a total of 983 say 1000hrs, my recharge is 3478AH which gives a average charge level of, 3478/1000, 3.48A which probably isn't too far off the mark? You can do a similar calc based on your mileage, might tell something.

I have a 59AH EFB.

The first set of readings I took after 2.5 years, below, still showed a fairly high resistance.

Sept 2021

IDE01834 Battery voltage 13.487 V

IDE01836 Battery current 2.639 A

IDE01837 Temperature of battery sensor 32 °C

IDE01838 Battery temperature 27 °C

IDE01839 Battery charge level 85 %

IDE01841 Battery internal resistance 6.6 mOhm

IDE01842 Usable battery charge 38 Ah

Edited 21 October, 202521 Oct by Johngerard

Ive still not got a definitive answer to my question

When I first press ignition all dash lights come on (test) then go off (battery light dosent come on at first click) then after about 15 seconds the yellow battery lights on and stays on till I start the car

Anyone else experience this.

9 minutes ago, Tonyduncan said:

Ive still not got a definitive answer to my question

When I first press ignition all dash lights come on (test) then go off (battery light dosent come on at first click) then after about 15 seconds the yellow battery lights on and stays on till I start the car

Anyone else experience this.

If the yellow battery lamp comes on with ignition on but no engine running is it not just to warn you that you have the ignition on but no engine running.

If it comes on whilst running it would be to warn of a charging problem.

What circumstances require the ignition to be on without running the engine. The infotainment should work if you switch it on without the ignition on.

1st click for accessories but no ignition on, after a while a battery message may come on.

2nd click ignition on dashboard lamp cycle to check they work but go off. Left in this position battery lamp to warn ignition on battery being drained unnecessarily.

3rd position operates starter motor

Everything I drive warns of ignition in position 2 but no engine started in some way.

With vehicles that i have driven with a start button . Pressing start puts ignition on. Applying brake at the same time operates the starter. so Pushing button alone is position 2.

Edited 21 October, 202521 Oct by Stonekeeper

Trying to eliminate things as start stop only works randomly

Has anyone got a octavia mk4.5 facelift and can confirm if this happens on there car ?

1 minute ago, Tonyduncan said:

Trying to eliminate things as start stop only works randomly

Start/stop can be the earliest sign of a battery issue.

When it doesn't happen is the stop/start lamp greyed out or crossed out on the dashboard.

If it is it means the system is working but conditions needed to work are not being met

38 minutes ago, Stonekeeper said:

Start/stop can be the earliest sign of a battery issue.

When it doesn't happen is the stop/start lamp greyed out or crossed out on the dashboard.

If it is it means the system is working but conditions needed to work are not being met

Yes that what I'm getting the thing is some days it will work for a few hours some not at all very random Ive also got 7 modules with faults all mention communication errors so im thinking it could be that if so many things have to be right for it to work.