It may depend on what was happening with the car, battery alternator between the two lots of 12 hours 5-amp charging but it's inevitable that a used 6.5 year old battery won't be as good as new but it all seems very reasonable, plenty of useful life left in the battery.

Don't get too bogged down with figures and percentages the battery wear, tear and useful life isn't a straight line, bit like tyre tread wear and fuel range left, depends on how the car is used in the future (that not even the great gods of VW computers and their programming can know exactly).

3 hours ago, Johngerard said:

From what I am seeing, the Stop/Start will operate (on this cart ) until the battery is on its last legs,

Generally, historically at least for other models possibly including a 2019 VW product the stop/start will at least at periods stop functioning when it should be functioning, way, way(, way) before the battery is on its last legs and unable to start the car. Based on the experience of others you can flog the battery to death over months of driving and have a good selection of warning lights and messages and unseen error codes greet you with greater repletion over shorter intervals or staying on and possibly finally joining the statistics of number one reason for breakdown call-outs (totally the battery's fault of course 😄).

My wife's then 3-year old AGM 60Ah battery took IIRC 15 hours to fully recharge on a cold winter's night using a Ring 4-amp charger maintainer and this was a preventative charge the battery wasn't 'low' by any VW (product) standards.

It was just that the car was doing lots of very short journeys at the time and must be fully functioning for the boss - ignoring the loud underside clonk(s) and squeak(s) the cold exasperates (me not the boss she just turns the radio up to la-la to) - and I certainly don't want to be farting about with it when it's very cold (!"£$%^& short-lived VW remote key).

Interesting stuff @Johngerard . Lets us know how things are once there are a few days / nights of very cold weather and maybe a few consecutive days.

@Johngerard What's the battery rated at, it'll say on the top or the side somewhere. Your data, while interesting, is meaningless without this number.

On 26/08/2025 at 12:54, nta16 said:

Could you not take it to a good (VW) independent where that should be easily possible if they've not already detailed the work or told you about it at collection, Dealerships are more interested in tick(lie)sheets and the staff looking for more chargeable work on your car to increase their revenue and profits.

Investigation might just be plugging in the scan tool, if available, then firing off the parts cannon rather than proper diagnostics which the staff may not be allowed to do for various reasons even if they want to and able. I see some good Dealerships might exist from what other members write but generally that's not my experience, then independent garages are often a let down. I've finally found an honest garage fairly local to us, they close for lunch and full weekends, that was a good sign to me, look after the staff to look after the customers, also recommended by reliable people we know.

Good luck to you, let us know how you get on.

You were spot on with what you said, apparently the battery is ok, again I didn't get the opportunity to speak with their technician. The engine management light was very likely the cause from a crack flexible pipe, something to do with the fuel breather I believe! The EML has been cleared along with the power to high indication. Car has been booked back in for next week to replace the pipe.

All my thoughts of what it was has gone out the window, I need to speak with someone next week to see exactly what was done. I find, at the time all the explanations satisfactory, until I get back home and start chewing it over.

I would dearly like to find a local garage that could deal with this and then have a better relationship with them hopefully.

38 minutes ago, Aldfort said:

@Johngerard What's the battery rated at, it'll say on the top or the side somewhere. Your data, while interesting, is meaningless without this number.

Can't see without taking the top off, VCDS states

IDE03256-MAS06105 Battery adaptation-Rated battery capacity 59 Ah

IDE03256-MAS06106 Battery adaptation-Battery technology EFB

IDE03256-MAS06107 Battery adaptation-Battery manufacturer JCB

IDE03256-MAS06108 Battery adaptation-Battery Serial Number 1111111111

1 hour ago, EMike said:

You were spot on with what you said

That'd be a true rarity but if you throw enough, er, mud at a wall eventually some of it might stick. 😄

1 hour ago, EMike said:

the cause from a crack flexible pipe

Possibly a pipe to do with air which upsets the computers and running of their systems and the engine - but that's just a guess and I'm far from knowing much/anything about mechanics (and the mysteries of how VW do things, the corporate mindset, other than what's been proven in courts, I've not kept up with the last VW bosses in court thing).

31 minutes ago, Johngerard said:

IDE03256-MAS06105 Battery adaptation-Rated battery capacity 59 Ah

IDE03256-MAS06106 Battery adaptation-Battery technology EFB

IDE03256-MAS06107 Battery adaptation-Battery manufacturer JCB

IDE03256-MAS06108 Battery adaptation-Battery Serial Number 1111111111

Yeap usual VW disregard for their 'rules' and standards with battery serial number of factory default ten ones (1111111111). The JCB IIRC is for Johnson Controls a big supplier to car manufacturers.

As I put before don't get too hung up on these figures from two different lots of computer programs (VW and VCDS) and as I almost put before and Aidfort actually did, as always with percentages (especially perhaps 100%) you have to ask percentage of what.

5-amps is closer to the one-tenth charging rate VWŠkoda put in the 'Owner's Manual' - you have a 59Ah so for tenth it would be a 5.9 amp charger, for the Heineken effect on batteries that have got to a low state of charge from regular use or other long slow drain I've always found using lower amp chargers is more effective (backed up by some stuff on the web but that means little) say 2 or 3-amp. Having said that I use a 4-amp for my wife's 2015 Fabia Mk3 (replacement) battery, as that's what I bought for it, and I do a very few occasional preventative charges rather than reactive charges (fire-fighting as some call such things).

If you had a newer VW model than 2019 you may not have got as far as 6.5 years on the battery, certainly not in its current condition based on other owner's experience at least and VW would tell, whoops, sorry, advise you to change the battery at 5 years, probably in your 'Owner's Manual' as it is in the 2019 (IIRC, 4-years later I think) VWŠkoda models.

Charging a battery for a modern car, particularly if taken too low in charge, requires two things that many people, particularly professionals in the car trade, have little in stock - time and patience.

If you've not got the instruction book for your charger you may still be able to get a pdf version from Lidl and Aldi's archives, here's one I got years back when trying to help the old farts with a certain marque of old (over-priced and over-valued) cars called "classics" - btw I was one of those old-farts but surprising (for some here) not so stuck in the past. 😄

IAN 383685_2110.pdf

Edited 31 August, 202531 Aug by nta16

NO fear of me getting hung up on these numbers but I do find them interesting. I would fairly confidently say though that had this battery been charged at at a constant 14.2/14.4V like all my previous cars to this one that I would see at least 10 years battery life because this car is operated very similar to the last Polo still in the family (20 years old now) and I only replaced that battery as I was passing it down the line.

Taking the smart BMS charging system, even though this battery was allegedly at 24A/65% SOC it was still only being (Alternator) charged at 13.5V and ~ 1.0A but, a few weeks/months ago when the SOC was 74% or so, it charged continuously at 14.4/14.8V for practically the whole of a two hour trip and only returned to 13.5V just before the trip end but it did again, (allegedy) reurn the battery to ~ 83% SOC, strange?

Re my smart charger, I would think that it did charge at 0.8/1.0A for the first 12 hours, which increased the SOC from 65% to 74%, and only maybe 0.2A for the other 12 hours, hence the SOC stayed exactly the same, I wonder would one of these other fancy chargers do any better? or can be set to "load" charging, ie say, you set it to 3 or 4A and the charger will increase the voltage to (try) and achieve this, otherwise, IMO, one has no control over the SOC except maybe to use the charger as soon as you get a new battery and assume/hope its at 100% SOC., what a PITA. I will connect my M.meter (10A) in series with the smart charger next time and see what its doing.

Edited 31 August, 202531 Aug by Johngerard

4 hours ago, Johngerard said:

Taking the smart BMS charging system

It's not smart (same as other "smart" devices) I'm not sure if it's even called smart, controlling yes.

With the battery charging you have done I don't see how a fancy (expensive) charge would do much, if any at all, better, yes charging lower amps might have added a bit but really it boils down to charging sooner than the 6.5 years possibly/probably but all might be incremental.

It's no real effort to fully charge a new battery before installation and if the battery is already well, or fully, charged at delivery it ain't going to take long is it. True the VW programming will want to get it down to around 80% for the minimal/pretence of fuel and emissions reductions, as we know VW were very concerned with emissions.

You can do nothing about the past but you could extend the future longevity of the battery but then it's a very small cost saving on a VW product with all its servicing requirements and shorter lived parts - but at least you've got all those marvellous features, "aids" and "assists" on the car that weren't on previous years. 😁

5 hours ago, Johngerard said:

I will connect my M.meter (10A) in series with the smart charger next time and see what its doing.

You could if you want. I just watch the initial voltage figures on the "smart" 4-amp Ring charger maintainer at the start of charging to give me an idea of how the charge might be and go on then occasional glances at the voltage reading to get an idea how things are going and when they might get to "FUL" on that charger maintainer.

Some think I spend lots of time on the car's battery but I really don't, very, very little, in fact I should check more often but I don't as I really dislike farting about with cars particular our cars (in the past now) and particularly the VW product my wife has now, just a very occasional, easy clean-hands work of, preventative recharging with the Ring to save upsetting the gods that are VW programming on the car and keep as much as reliable as they can be on such a car, not that it doesn't still make me suffer.

During a 20 minute daylight run (daylight) the battery charged at a average of 1.6A at 13.66V, including a average of 16.9A at 14.93V on the Overruns, the SOC was 75% with a usable battery charge of 28AH, (59AH EFB battery). I then connected the charger with my multimeter in series measuring the charging amps, it went to 14.4V for ~ 15secs charging at 3.8A then fell to 13.4V charging at a constant 0.8A for the next 2 hrs and then fell to 13.1V at 0.2A for a remaining monitored time of 1 hour, then removed it, SOC 76% usable battery charge 28AH.

While the Alternator just eventually might get the SOC back up to 83% if the car was driven long enough, it doesn't seem very clever since the battery can clearly absorb up to 30A and even with all the auxiliaries switched on, was being charged at 12/15A on the overruns.

The charger it seems would never get the SOC back up, wonder would the fancier/more expensive ones fare any better.

Edited 4 September, 20254 Sep by Johngerard

5 hours ago, Johngerard said:

SOC 76% usable battery charge 28AH.

Are these VW /VCDS figures?

5 hours ago, Johngerard said:

the SOC was 75% with a usable battery charge of 28AH, (59AH EFB battery). I then connected the charger with my multimeter in series measuring the charging amps, it went to 14.4V for ~ 15secs charging at 3.8A then fell to 13.4V charging at a constant 0.8A for the next 2 hrs and then fell to 13.1V at 0.2A for a remaining monitored time of 1 hour, then removed it, SOC 76% usable battery charge 28AH.

You are you saying after 3 hours on your charger maintainer the battery went from a recorded 75%, 28Ah to 76% 28Ah(?).

5 hours ago, Johngerard said:

The charger it seems would never get the SOC back up, wonder would the fancier/more expensive ones fare any better.

IIRC you have used it on two separated 12 hour session before, now this 3 hour go, if you want to why not buy the fancier (much more) expensive charger maintainers and find out for yourself (and if you report back your findings the benefit of other members here, at your financial cost) or perhaps borrow a fancier (much more) expensive one from someone that has already bought it or got it as a present.

Yes, a VCDS, the 75% to 76% isn't borne out by the 28AH each time.

During the previous charging sessions which I now know were (probably) 0.8A for 12 hrs and then 0.2A for another 12 hrs, the SOC went from 65% to 74% in the first 12hrs and no change in the second 12hrs, based on this, I would think, as you suggested, that any of the other chargers would perform any differently, I will be doing another 2 hour trip in the not too distant future so will see if the Alternator will increase the SOC even though averaging just 1.6A while driving at least short journeys, the last time it was showing 83% (after a 2 hr trip), the usable battery charge was, I think, 32AH, not bad, when compared to the first readings I took when the car/battery were 2yrs 8mnts old.

14/09/2021

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

12/07/2025

IDE01836 Battery current -4.924 A

IDE01837 Temperature of battery sensor 35 °C

IDE01838 Battery temperature 37 °C

IDE01839 Battery charge level 83 %

IDE01841 Battery internal resistance 8.0 mOhm

IDE01842 Usable battery charge 33 Ah (59AH Battery, original, 6.5 years old)

IDE01843 Battery voltage at rest 12.6 V

IDE01948 Battery internal resistance not normed 5.6 mOhm

Edited 4 September, 20254 Sep by Johngerard

I'm going to chip in again despite the fact I said I would not.

The data in the last post tells you everything you need to know.

In general the data is showing you the slow decline of the battery, it's a shame you don't have the data going back to when the battery was brand new. You'd be able to graph out it's charge holding capacity from new which would give a clearer picture.

BTW - what multi-meter do you have that can measure AMPS at that level?

Other than my previous comments about figures I thought your figures might cause some more comment, I must admit I thought they'd be sooner and more of them. Same as yours, and from others previously, figures from using a battery charge, if accurate of course, would be against some internet information and beliefs.

As put it would have been very interesting to see figures from when the battery was new and used and the VW program holding the battery charge at the around 80% especially against your your figures when the battery, alternator and car were two of use old.

Monitoring the battery at 2 years of use and 6.5 years of use is a (very little) bit like looking at the fuel gauge and deciding when you want to refill the tank (with the tank contracting with use and time).

3 hours ago, Aldfort said:

I'm going to chip in again despite the fact I said I would not.

The data in the last post tells you everything you need to know.

In general the data is showing you the slow decline of the battery, it's a shame you don't have the data going back to when the battery was brand new. You'd be able to graph out it's charge holding capacity from new which would give a clearer picture.

BTW - what multi-meter do you have that can measure AMPS at that level?

The only time I use my multimeter 0-10A scale is to measure the charging current when I'm using the smart charger which I know can't exceed 5A, just change over one lead on the meter, any other measurements are taken with the VCDS, any value you see with a IDEO prefix is from the VCDS.

Yes, a pity I didn't take a set of readings when new but there are 4 years between the two sets above which give 38AH usable battery charge after 2.7 years vs 33AH after 6.5 years.

I changed the battery in my daughters Sharan last December and would be confident that I coded it properly but the readings taken immediately afterwards are a bit confusing, the battery is a 70AH, 096 Ecoforce AFB Fiam and the "70 Battery Size" seems to bear this out but it then says "100 Ah Available Battery Charge". My battery internal resistance showed 6.6mOhms after 2.7 years and 8.0mOhms after 6.5 years, the cranking voltage drop at the battery terminals that I measured last week with my trusty M.meter was

12.17-10.7, 1.47V which suggests a cranking load of 184A with a battery resistance of 8mOhms, anyway that's the simple test I use if anyone's battery is suspect, just measure the voltage while cranking, if below say 9.5ish volts then something not right, a M.meter will show up most of these problems and did 50 years or more before VCDS was a thought.

Sharan New Battery December 2024

70 Battery Size

14.848 V Battery Voltage

8.1 A Battery Current

100.0 % Battery Aging (Power)

4.6 mOhm Internal Resistance Battery

2.2 mOhm Internal Resistance Battery (normalized)

100 Ah Available Battery Charge

11.40 V Battery Quiescent Current

1 Total Engery Throughput II

0 Total Engery Throughput I

On 25/08/2025 at 18:47, nta16 said:

Other way round.

For you and perhaps others maybe.

You're shutting the gate after the horse has bolted and blaming the horse. You can obviously afford the costs and not worried about a bit of waste, you do what you want to do no-one is stopping you, but why not let others offer alternatives, these can easily be ignored or taken up.

By the time a modern car has engine starting problems the battery is very low indeed, one of the last things to go, either the battery has been well drained in which case it might be easily recharged with the very simple method mentioned countless times or if the battery has been flogged far too often and far too long the chance of reviving the battery by recharging get significantly less and if the user is the type to keep repeating this behaviour then yes probably best to replace the battery - or if someone would just sooner replace the battery that's their choice but you'd hope they'd not moan about it.

Loas test, as with any other test, should be repeated, first test might show reasonable, but if first test is very bad then the rare thing 'common sense' could be introduced.

When are we getting off this roundabout, don't you ever get dizzy . . .

On 25/08/2025 at 18:47, nta16 said:

No im staying on it because I need a bigger hammer to get through to the really slow ones

I do enjoy reading all these comments, I wish sometimes I was a little more knowledgeable. I thought I had a pretty good basic idea of this but the more I read.....

Oh, I have had the car repaired! It was the evap pipe and canister (god knows what that is) only £300!!! Yes I can see how it's a licence to print money.

Although I understood, I think, the vehicle high power indication, I did mention this in the beginning and was told this would be sorted when work was complete.

Well the indication is still there, so I've asked the chap on reception to speak with the technician and explain to me what this is, and why I'm still getting it.

I know it's related to stop/start, and pleased in a way that it doesn't work, but would like them to tell me to see what their idea is. Mike

On 07/09/2025 at 11:04, EMike said:

Oh, I have had the car repaired! It was the evap pipe and canister (god knows what that is) only £300!!! Yes I can see how it's a licence to print money.

Bits of plastic and 'rubber' faulty or damaged perhaps. When you fill the fuel tank and the petrol station better practice is to stop filling at the first clip of the petrol station filler pump, not carry on to round up to any particular figure or get more in.

On 07/09/2025 at 11:04, EMike said:

Although I understood, I think, the vehicle high power indication, I did mention this in the beginning and was told this would be sorted when work was complete.

Well the indication is still there, so I've asked the chap on reception to speak with the technician and explain to me what this is, and why I'm still getting it.

I know it's related to stop/start, and pleased in a way that it doesn't work, but would like them to tell me to see what their idea is.

Depends which work or bit of work is to be completed, if you still have the message then that bit of work hasn't been completed (or started?).

You could ask if there are any computer program updates are yet to be installed for your car, that might clear issues (and probably create others if like MS updates).

If your (Mike's) consumption of electric in the car is too high they should be able to tell you where and why, are you running a mega sound system and video cameras on with equipment plugged in to make breakfast, brunch, lunch, tea, dinner. 🙃

On 04/09/2025 at 23:33, Johngerard said:

Yes, a VCDS, the 75% to 76% isn't borne out by the 28AH each time.

During the previous charging sessions which I now know were (probably) 0.8A for 12 hrs and then 0.2A for another 12 hrs, the SOC went from 65% to 74% in the first 12hrs and no change in the second 12hrs, based on this, I would think, as you suggested, that any of the other chargers would perform any differently, I will be doing another 2 hour trip in the not too distant future so will see if the Alternator will increase the SOC even though averaging just 1.6A while driving at least short journeys, the last time it was showing 83% (after a 2 hr trip), the usable battery charge was, I think, 32AH, not bad, when compared to the first readings I took when the car/battery were 2yrs 8mnts old.

14/09/2021

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

12/07/2025

IDE01836 Battery current -4.924 A

IDE01837 Temperature of battery sensor 35 °C

IDE01838 Battery temperature 37 °C

IDE01839 Battery charge level 83 %

IDE01841 Battery internal resistance 8.0 mOhm

IDE01842 Usable battery charge 33 Ah (59AH Battery, original, 6.5 years old)

IDE01843 Battery voltage at rest 12.6 V

IDE01948 Battery internal resistance not normed 5.6 mOhm

Did this 2 hour trip and its quite apparent that the BMS system will now only charge to ~ 70% SOC, it does charge at ~ 14.9V/20A, but only for 15 secs or so after a (stop/start) restart and then falls back to

13.5V but does go to 14.9V on overrun.

15:22:30 12092025 immediately after 2 hour country trip. (VCDS readings taken with engine idling)

  IDE01834   Battery voltage 13.499 V

  IDE01836   Battery current 2.828 A

  IDE01837   Temperature of battery sensor 34 °C

  IDE01839   Battery charge level 71 %

  IDE01841   Battery internal resistance 7.8 mOhm

  IDE01842   Usable battery charge 26 Ah

  IDE01843   Battery voltage at rest 12.4 V

  IDE01948   Battery internal resistance not normed 7.8 mOhm

  IDE07681-MAS06086   Battery total charging throughput-Total re-charge 3422.3 Ah

  IDE07681-MAS06087   Battery total charging throughput-Entire energy throughput 3611.6 Ah

On 12/09/2025 at 21:33, Johngerard said:

Did this 2 hour trip and its quite apparent that the BMS system will now only charge to ~ 70% SOC, it does charge at ~ 14.9V/20A, but only for 15 secs or so after a (stop/start) restart and then falls back to

13.5V but does go to 14.9V on overrun.

15:22:30 12092025 immediately after 2 hour country trip. (VCDS readings taken with engine idling)

  IDE01834   Battery voltage 13.499 V

  IDE01836   Battery current 2.828 A

  IDE01837   Temperature of battery sensor 34 °C

  IDE01839   Battery charge level 71 %

  IDE01841   Battery internal resistance 7.8 mOhm

  IDE01842   Usable battery charge 26 Ah

  IDE01843   Battery voltage at rest 12.4 V

  IDE01948   Battery internal resistance not normed 7.8 mOhm

  IDE07681-MAS06086   Battery total charging throughput-Total re-charge 3422.3 Ah

  IDE07681-MAS06087   Battery total charging throughput-Entire energy throughput 3611.6 Ah

Battery, believe it or not, back up to 82% SOC after another 2 hr round trip, on the 1 hr outward trip. its normal 14.8V on overrun only, otherwise its normal 13.5V but on the return trip charged at a constant 14.4V continuously for 35 minutes and then back to its old ways.

I won't post again until either the battery or I die!!

18:57:34 20092025

  IDE01834   Battery voltage 12.313 V

  IDE01836   Battery current -4.420 A

  ID01837   Temperature of battery sensor 21 °C

  IDE01839   Battery charge level 82 %

  IDE01841   Battery internal resistance 7.4 mOhm

  IDE01842   Usable battery charge 33 Ah

  IDE01843   Battery voltage at rest 12.5 V

  IDE01948   Battery internal resistance not normed 5.8 mOhm

  IDE07681-MAS06086   Battery total charging throughput-Total re-charge 3441.7 Ah

  IDE07681-MAS06087   Battery total charging throughput-Entire energy throughput 3630.8 Ah

Yes running/charging voltage characteristics can end up being a bit strange or not what you might have expected, I still have the DVM - cheap plug in type, plugged in permanently in my wife's 2015 Polo, its factory fitted battery is still okay though as should be expected it is dying slowly - having lived 10 years is fine by me, one day it will no longer in fit for that job, hopefully I'll get enough of a warning to avoid a "non start" situation. Auto stop/start still gets enabled quickly if it allow it to.

Does the DVM show charging characteristics like mine, (DVM), normally only 14.8V on the overrun? and have you taken any VCDS readings recently?

Yes, but as my EFB is over 10 years old, unless the journey is more than maybe 20 miles, the "Normal" charging voltage will be closer to the max - which is what it will always be when on the over run.

The 2015 6C version of Polo has an earlier version of controller, so the readable data does not look the same as your later car, there is/was a guy on the similar age of Polo to your car on the Polo forum, who tends to post a set of up to date readings regularly - or did.

I should grab the current data from that Polo to see if/how it has changed over the past 12 months.

I got the feeling that I did manage to "revive" that battery or the charging system by running a battery reg'ng routine using VCDS and changing the serial number - that was a few years ago though.

I have an 2011 Audi S4 and when it was 10 years old, I replaced its AGM with a new one, the only reason that I did that was due to that car only being used to travel long distances away from home, so I didn't fancy ending up needing to replace its battery when "away". I was disappointed that I did not see a quick change in data in its battery management controller, but I've not kept a record of any changes/improvements that it has made over the past 4.5 years. Its old AGM battery is kept charged and when tested annually - out of circuit, it shows a very high CCA - which is exactly what you tend to find if testing a new battery out of the car, ie a CCA value of at least 125% of its rated value.

What you can see from the DVM really depends on how you drive the car, typically I can end up coming to halt at traffic lights after a 10 mile run, and auto stop/start is currently not enabled, I've noticed that if I drive "quietly" this will happen frequently, and if I drive more "aggressively" auto stop/start will always be available at that point in the journey. I've put that down to the car having harvested the stored charge as so it is not in a state to auto stop/start.