Johngerard

The first battery scan on this car was only a few days after purchase, April 2026 and its internal resistance was even then 6.8mOhms, it is was 7.4mOhms on 7th Oct (2026), 6 months later. My almost 8 year old January 2019 Polo wasn't scanned until Sept 2021, (2yrs 8 months old) and its resistance was 6.6mOhms, it was 7.6mOhms in June 2026 (7 yrs 5 months old). Both have 59AH EFB Batteries.

That's interesting, one might imagine that the 2,4, 6 or 8 amp settings are maximum settings, otherwise, if the charge rate (amps) is constant then the voltage must be changing, once my SOC reaches ~ 75% SOC then the charging rate is down to a measured 0.38A as the charger effectively goes to maintenence mode at around 12.7V and the charging rate will fall still lower as the SOC increases so would take days to reach 90% SOC. I would expect your charger to behave similar to mine, below, at least in auto recharge.

How long do you leave the battery on charge at each 2 month charging interval?, does it display the charging voltage and if so do you leave it charging until the voltage falls to some known/recommended level?.

My less than a year old battery (and car) would makes a very big meal of trying to reach 85% SOC (don't even mention 100%), you can see below that it took 7.5hrs (smart charging) to get a tiny increases in SOC by 2% and a usable battery charge increase of 1AH, the battery energy counter shows a increase of a average of 2.8A over 7.5hrs, 0.37A per hour. My M.meter, in series with the charger showed a charging rate of < 0.2A for the majority of the 7.5 hr charging period. Also, later, on a 25 minute non stop run under varying driving conditions, the DVM showed that the charging voltage never went higher than 13.4V even on overrun and spent most of its time charging at 12.8V. Maybe a "smarter" smart charger than mine would get the SOC up to 100% eventually, if so, I'd like to see it confirmed by someone with VCDS. MAS16744-IDE01836 12-volt battery-Battery current -8.825 A MAS16744-IDE01839 12-volt battery-Battery charge status 75 % MAS16744-IDE01841 12-volt battery-Battery internal resistance 7.4 mOhm MAS16744-IDE01842 12-volt battery-Usable battery charge 26 Ah MAS16744-MAS06086 12-volt battery-Total re-charge 592.4 Ah MAS16744-MAS06087 12-volt battery-Entire energy throughput 598.1 Ah MAS16745-IDE01843 Quiescent current management-Battery voltage at rest 12.5 V After a further 7.5 hrs charging at 12.7, occasionally 13.4V. Charger is a Ultimate Speed ULGD 5.0 C1, (a 5.0A charger) MAS16744-IDE01836 12-volt battery-Battery current -6.729 A MAS16744-IDE01839 12-volt battery-Battery charge status 77 % MAS16744-IDE01841 12-volt battery-Battery internal resistance 7.4 mOhm MAS16744-IDE01842 12-volt battery-Usable battery charge 27 Ah MAS16744-MAS06086 12-volt battery-Total re-charge 594.3 Ah MAS16744-MAS06087 12-volt battery-Entire energy throughput 599.0 Ah MAS16745-IDE01843 Quiescent current management-Battery voltage at rest 12.5 V

After exactly 2hrs (5A charger) the charging went from initially 13.2V to a max of 14.4V before reducing to 13.2V. SOC went from 53% to 77% Usable Battery Charge 16A to 27A Voltage at Rest 12.1V to 12.5V.

Just noticed (Jan 2026 ) car charging at a constant 14.4V ish over the past few days, this car is only averaging ~ 7 miles/day but stop/start still operating perfectly at 53% SOC, will stick my smart (max) 5A charger on it over the next few nights and see can I restore it to around 80% SOC. 12:38:49 Jan 2026 Polo 95BHP TSI 2638kms,1639miles. Engine Idling for ~ 5 minutes. Think battery is a 59AH EFB. IDE00019 Voltage terminal 30 14.4 V MAS16744-IDE01836 12-volt battery-Battery current 24.612 A MAS16744-IDE01837 12-volt battery-Temperature of battery sensor 28 °C MAS16744-IDE01839 12-volt battery-Battery charge status 53 % MAS16744-IDE01841 12-volt battery-Battery internal resistance 7.6 mOhm MAS16744-IDE01842 12-volt battery-Usable battery charge 16 Ah MAS16744-MAS06086 12-volt battery-Total re-charge 569.2 Ah MAS16744-MAS06087 12-volt battery-Entire energy throughput 578.1 Ah MAS16744-MAS22232 12-volt battery-Battery aging: charge-related 88 % MAS16745-IDE01843 Quiescent current management-Battery voltage at rest 12.1 V IDE02756 Number of manual engine starts 936 IDE02757 Number of automatic engine starts 422

I must have a look sometime to see if VCDS records the total engine starts. 24500 starts at say ~ 250A per 2sec (max)cranktime = 3406AH, if your figure refers to 14500AH each for battery truput and charging then ~ 11094AH used during ASS stopped time, ~ 0.45AH per stopped time??.

Is that using VCDS??, what is your total mileage?.

Trying to get the SOC back up by driving the car, especially with the present smart charging is not a great idea IMO and just a waste of fuel The family, Jan 2026 Polo,only seems to keep the SOC around 72/74% and a round trip last May dropping someone off at the Airport bears out the very low charging rates. The average charging ignoring engine off time and starting load was ~ 3.9A at 13.51V and, even after 23 miles the charging rate was less than 4A on overrun at 14.8V (SOC still only 72%). However, I will let it soldier on, the other 7.5 year Polo now passed down the line previously operated almost the same as this one and if I can get 8+ years out of the battery in both I will be happy enough I think, stop/start always works when requested so perhaps running at ~ 70% SOC isn't that such of a disaster after all?. LOG-261C10532-logged Airport Battery Data2 74%.xlsx

SOC stands for State of Charge. Also, If ASS is not available when it should be then the symbol will still display but with a line through it.

Suggest buying a DVM (digital Volt Meter) and plugging it into the cabin power point, permanently if not being used for anything else, and monitoring the voltage while driving normally, coasting etc. If the battery SOC is up around 80% then the DVV will show 14.5/14.8V on overrun and ~ 13.0/13.6V with accelerator pressed, if the SOC is down around 75% then its more than likely that the charging rate is 14.5/14.8V under all driving conditions. My over 7.5 year old Polo petrol 65BHP (Original) battery SOC has often been down around 75% but stop/start never failed to operate any time I care to use it. The max SOC is 85%. VCDS 10Friday,05,June,2026,10:45:58:555 42,715 kms/26,542miles. IDE01834 Battery voltage 12.193 V IDE01836 Battery current -4.950 A IDE01839 Battery charge status 77 % IDE01841 Battery internal resistance 7.6 mOhm IDE01842 Usable battery charge 28 Ah IDE01948 Battery internal resistance not normed 6.0 mOhm IDE07681-MAS06086 Battery total charging throughput-Total re-charge 3890.7 Ah IDE07681-MAS06087 Battery total charging throughput-Entire energy throughput 4091.0 Ah Battery Capacity 59AH.

Its amazing how sensitive some of these engines seem to be when changing from 95 octane to 98 octane apparently cures the problem, mind you, in Spain there are at least 3 different choices of petrol, around here, its practically all E10 (95 octane) and you will have to travel to get E5.

Under no circumstances whatsoever should 0.37kgs of sediment or whatever you wish to call it build up in 3 years and 23K miles, I have had 3 different family VWs, each well over 20 years old when scrapped and never had any problem like that, that canister is supposed to trap vapours, can only imagine that overfilling the tank at every refill might cause this in such a short period, it would be interesting though to see if all all new canisters are of equal weight.

There might be another one in the door pocket.....His & Hers then?.

I used to clean a 2005 Polo throttle body but I did it in situ, remove air cleaner, switch on ignition and put a "brick" on the accelerator, this will/should open the throttle valve fully to allow gentle cleaning of most of the throttle body, the revs used be on the high side after the clean for a few miles of driving but used to settle back down to normal. I have VCDS but never used it after cleaning. Your 2004 Fabia may have still had a cable operated throttle valve but the idling is/was still done electronically, the motor on these used to fail occasionally, I replaced them on a few friends 2000 Boras with used ones, again (and I didn't have VCDS then), idling speed would normalize after a few miles. Also, as suggested above......"check the brake servo vacuum hose for splits or cracks at the junctions of the hard plastic sections"