The engine isn’t start stopping either, which others have identified as an early warning of a low battery level. Just sitting on the drive the latest tech cars are still making demands on the battery.

To date, I’ve only charged the battery once with the CTEK and checked the voltage after two weeks of few and short duration drives. It showed 12.1v on the Ancel BST60 which when I searched for results suggested around a 50% charge level. So maybe a weekly top up charging schedule is required due to driving almost exclusively in heavy urban traffic.

 Amazing that Skoda haven’t incorporated a voltmeter in the instrumentation or fitted a better battery. The car is not two years old so replacing the battery isn’t appealing.  An AGM battery would be a better unit but I’ve read they are very sensitive to extreme temperatures and best not mounted in the usual under bonnet location.  The simply clever Skoda systems would require that a specialist recode the car to accept a new battery type.

You can get a 0.2v or 0.3v drop just from the car's computer systems doing their stuff parked up, more if extras are added to the car. Taking a reading just after the car has been driver could give a false high reading

Measure of battery voltage can involve other variables.

I think battery gauges are going back on cars but modern drivers might not understand them and older drivers forgot how to read them.

The coolant temperature needle gauge has for a few decades been biased to read 90c for driver reassurance rather than the real variable reading, in the 70s the markings were removed from coolant gauges to stop drivers worrying about the variables, same would go for 12v battery gauges.

1970s

1960s

"Comfort" coolant temperature gauges have been a feature of VW and VAG? group cars since at least 2000, the gauges do display numbers, 50C to 130C, they are supposed to roughly give a true reading up to 70C although my 2019 Polo seems to say, up to ~ 60C and will then rise rapidly to a constant 90C but will again read correctly from a alleged 107C, I did prefer the simple type which would sit under normal driving conditions right in the centre of the gauge, might only move by the thickness of the indicator and only moved up really in idling conditions until the rad fan cut in via its thermoswitch.

I don't know what the thermoswitch settings are in this Polo but on another 2005 Polo are set.....

Fan Speed 1 ON at 91C to 97C.    OFF at 91 to 84C.

Fan Speed 2 ON at 99C to 105C.  OFF at 98 to 91C.

Thermostat begins opening at 84C.  Fully Open at 98C.

VW Polo 2019

Coolant Temp

VCDS/Car

52 /52

53/55

56/58

58/62

60/65

63/69

64/72

66/74

68/78

69/82

71/84

73/86

74/88

75/89

75/89

Edited 16 July, 202516 Jul by Johngerard

So your 2019 has a digital coolant gauge, my wife's has a needle dial which is good enough as if I want to know when the engine is up to temperature I use the digital oil temperature gauge which can be displayed in the maxidot display.

I like the term comfort, first time I've seen that.

On British "classic" old over-priced and over-valued cars with the truer reading mechanical dual gauges you could watch the gauge needles move with the actions of the car, or rise if stuck in traffic (not that what they displayed was always accurate) but you got used to normal readings for your car and with these unbiased gauges only inexperienced owners would worry about the numbers others got or whether the needle sat in the middle or on 'N'. A V8 engined owner put sitting in traffic for a long time on a hot day he had the 'water' needle go into the upper section of the 'oil' without any engine overheating issues, some inexperienced owners would have called the breakdown services.

How modern drivers interpret any 12v battery gauges in their cars I've not seen reported, I don't think (could well be wrong) they're on the Fabia Mk4(?).

My DVM cost ~ £5 and also displays the interior temperature which most cars do not, even with all their fancy AC controls. I can leave it plugged in permanently as no parasitic loss because the ignition must be on to power the auxiliary power socket.

Shortly before a 50 mile trip, VCDS showed a battey 73% SOC & "at rest" 12.4V, the DVM never fell below 14.1V until the ~ 1 hour trip was almost completed but then fell to 13.2V and VCDS then showed a 83% SOC and 12.6V "at rest".

Edited 17 July, 202517 Jul by Johngerard

As long as it's about right it's another thing to gauge by, as I tell my wife they call them gauges and not accurates and you need to add reference and prospective, indicated 60 mph might not be fast on an empty motorway but scary on a wet, dark, twisty country road and you might want to ignore the TwatNav directions when you can clearly see you will be driving into a river, judge how to use any information wisely.

Edited 17 July, 202517 Jul by nta16
ETA: change 70 to 60

One quite big problem with VAG cars is that if you dont lock them they stay in a state of readiness which uses battery power. The proper thign to do, even in your garage is LOCK IT and everything shuts down and therefore doesnt affect the battery.

A charger like mine, a CTEK Mx 5 can be left hooked to the car semi permanently without doing any harm and thats what the nifty connector is for. When my Passat battery was starting to die I had it hooked up in the garage for several months.Kept the battery up to charge but ultimately it died anyway.

36 minutes ago, Exkiwi said:

When my Passat battery was starting to die I had it hooked up in the garage for several months.Kept the battery up to charge but ultimately it died anyway.

Prevention is better than cure, if you wait until the damage is too much then you'll not get the best recovery.

I'm not sure, but even unlocked most things will go to sleep after a time anyway/ - no doubt someone will know and even perhaps have proof - ? @rum4mo ?

Edited 17 July, 202517 Jul by nta16
ETA: spelling

A VW Bora that was in the family for 22 years had a measured parasitic loss of 40mA, I used to regularly leave it at the airport for 10 days, total parasitic loss of 9.6AH, but never a problem in starting the car on return, right up to the time I replaced the battery after 12 years , purely as a precautionary measure as I was passing the car down to one of the children. A almost 21 year old Polo still in the family has always had a very high parasitic loss of 90mA for some reason or other, both these cars, like all VW pre smart alternators charged at a constant 14.2V.

Have never measured the present car parasitic loss as I don't want to disconnect the battery to do so.

21 hours ago, nta16 said:

Prevention is better than cure, if you wait until the damage is too much then you'll not get the best recovery.

I'm not sure, but even unlocked most things will go to sleep after a time anyway/ - no doubt someone will know and even perhaps have proof - ? @rum4mo ?

Correct, even with any of all "openings" left open.

Well that is or was my findings covering a 2009 SEAT Ibiza, 2011 Audi S4 and 2015 VW Polo - and in VW Group land, I'd think that "one size fits all" in this respect.

21 hours ago, Johngerard said:

A VW Bora that was in the family for 22 years had a measured parasitic loss of 40mA, I used to regularly leave it at the airport for 10 days, total parasitic loss of 9.6AH, but never a problem in starting the car on return, right up to the time I replaced the battery after 12 years , purely as a precautionary measure as I was passing the car down to one of the children. A almost 21 year old Polo still in the family has always had a very high parasitic loss of 90mA for some reason or other, both these cars, like all VW pre smart alternators charged at a constant 14.2V.

Have never measured the present car parasitic loss as I don't want to disconnect the battery to do so.

There is a way to introduce a "series" current measuring device without "wakening" these cars up, just clamp one side of a DMM set on current measurement to the local body earth using a crock clip, have a long sharp probe on the other "side" of the DMM and pass it down onto the battery earth post, now slacken off the earth clamp and lift it up "over" the long sharp tipped probe - obviously you need to wait 20 or 30 minutes after switching the car off or opening any "openings" before doing this to allow the controller to go to sleep.

It may be that different and/or newer models might take longer and longer to go to (partial perhaps) sleep. I've recharged the battery on my wife's 2015 Mk3 Fabia with bonnet open but car locked (but not bonnet catch shut) and with car unlocked and I've not noticed a difference in time but I haven't noted any readings or lengths of time as a comparison.

Even if recharging at what many would take as acceptable level of state of charge at 4-amps it still takes many hours to fully recharge the battery to full (or "FUL" on my Ring charger) and I know the VW system will get it back to say 80% but it's still worthwhile to me to get the battery to its 100% for battery and alternator (and mpg that I'm not that bothered about in an overweight, overwheel'd, overtyr'd modern car with 5 seats and only me in it).

My 2024 Fabia Mk4's battery, after being fully charged using my CTK MXS 5.0 charger, reads about 12.4V when a reading is taken with a multimeter at the battery terminals. This 'low' reading doesn't bother the car's starting, running, Stop/Start system, electronics, etc. and I'm unconvinced that bazz2004's Fabia's electronics/software 'glitches' are starter-battery-related. (Obviously, it's POSSIBLE that they are, but PROBABLY not.)

Out of idle curiosity, I shut the my car's bonnet, got in the car, made sure all the doors and windows were shut, locked the car using its key-fob and then immediately took voltage readings at the 12V power-outlet beneath the front armrest. The initial reading was 12.1V, but this gradually climbed to 12.4V when it stabilised. This seems to confirm (as has been mentioned above) that, when the car is unlocked and 'ready-to-go', there is a substantial current drain to maintain the car's electrical/electronic systems and this will continue until the car is locked and has 'shut itself down'.

My car's Owner's Manual includes the following advice

Recommendations when the vehicle is stationary for more than three weeks

• Disconnect the negative terminal of the 12V battery

This isn't that easy with a Mk4, but it does suggest that parasitic drain is recognised as being quite high and, consequently, it makes good sense to regularly charge a Mk4's battery if it is being driven infrequently.

2 hours ago, DerekU said:

This seems to confirm (as has been mentioned above) that, when the car is unlocked and 'ready-to-go', there is a substantial current drain to maintain the car's electrical/electronic systems and this will continue until the car is locked and has 'shut itself down'.

No it's doesn't really, it does confirm the drain is less after locking but that could also be the case after a time if the car is left unlocked and items go to sleep but after a longer time.

Did you switch the interior alarm off or sit very still inside the car so the alarm didn't go off.

The (about) 0.3V difference is what I'd expect from a 2024 Fabia but on fully recharging the 4 year old AGM battery on my wife's 2015 Fabia Mk3 with the £25 Ring charger maintainer I'd expect to see higher than 12.4v at battery terminal posts with my not expensive digital multimeter, more like 12.8v or 12.9v if I was to bother but it depends how long after fully recharging the battery and lots of other variables.

Despite what many think the need to more than just rely on the alternator for charging on modern vehicles used (and unused) in various ways has been with us for quite a while particularly with the over-complex German marques (not as clever as they think they are with their systems, and programing) hence it being part of the number reason for breakdown call outs and so many threads and posts on sites like Briskoda and others.

When VW first put in their 'Owner's Manuals' about disconnection the battery if the vehicle isn't used for x-weeks I don't know but from the earliest Fabia Mk1 'Owner's Manual' VW order that battery "must" be replaced if older than 5 years!

Edited 19 July, 202519 Jul by nta16

9 minutes ago, nta16 said:

No it's doesn't really, it does confirm the drain is less after locking but that could also be the case after a time if the car is left unlocked and items go to sleep but after a longer time.

Did you switch the interior alarm off or sit very still inside the car so the alarm didn't go off.

The (about) 0.3V difference is what I'd expect from a 2024 Fabia but on fully recharging the 4 year old AGM battery on my wife's 2015 Fabia Mk3 with the £25 Ring charger maintainer I'd expect to see higher than 12.4v at battery terminal posts with my not expensive digital multimeter, more like 12.8v or 12.9v if I was to bother but it depends how long after fully recharging the battery and lots of other variables.

Despite what many think the need to more than just rely on the alternator for charging on modern vehicles used (and unused) in various ways has been with us for quite a while particularly with the over-complex German marques (not as clever as they think they are with their systems, and programing) hence it being part of the number reason for breakdown call outs and so many threads and posts on sites like Briskoda and others.

When VW first put in their 'Owner's Manuals' about disconnection the battery if the vehicle isn't used for x-weeks I don't know but from the earliest Fabia Mk1 'Owner's Manual' VW order that battery "must" be replaced if older than 5 years!

That instruction sounds rather like the previous VAG UK advice on cambelt replacement intervals - now changed!

Yes but they still want revenue and profit from premature changes of batteries.

Newer models I think went to changing the battery at 4 years with some owners changing before that but I note in the latest 7/2025 Fabia Mk4 'Owner's Manual' there no mention a time to change the battery but that - "The specialist garage checks the condition of the 12V battery during servicing.".

And I've seen a post on Briskoda saying (Dealership?) offering to recharge the battery for £40.

And -

Recommendations when the vehicle is stationary for more than 3 weeks

• Disconnect the [ negative ] pole from the 12V vehicle battery 12-volt vehicle battery.

• Charge the 12V car battery every 4 weeks.