Is the 12v battery covered under VWs 3 year warranty?

[Johntheo1]

Another set of readings, car now 4 years & 7 months old. (4.583 yrs)
VAG reckon that useful battery life is ~ 50 X battery capacity, in my case 50*59 = 2950AH so depending on which value below is used, my battery life is either 2950/2187*4.583, 6.18 years or 2950/2342.2*4.583, 5.8 years, watch this space.

20:27:49 Mileage 22652KMS, 14076 MILES
IDE01834 Battery voltage 12.175 V
IDE01836 Battery current -4.356 A
IDE01837 Temperature of battery sensor 18 °C
IDE01839 Battery charge level 73 %
IDE01841 Battery internal resistance 7.0 mOhm
IDE01842 Usable battery charge 27 Ah
IDE01843 Battery voltage at rest 12.4 V
IDE01948 Battery internal resistance not normed 5.4 mOhm
IDE07681-MAS06086 Battery total charging throughput-Total re-charge 2187.0 Ah
IDE07681-MAS06087 Battery total charging throughput-Entire energy throughput 2342.2 Ah
(battery capacity 59AH)

Edit: Set of readings (idling) with headlights, HRS and cabin fan to speed 4.

Address 19: CAN Gateway (2Q0 909 901 ) Engine Idling, fan speed 4, HRS & Headlights ON.
15:44:06 02/08/2023
IDE01834 Battery voltage 13.280 V
IDE01836 Battery current 3.232 A
IDE01837 Temperature of battery sensor 21 °C
IDE01838 Battery temperature 22 °C
IDE01839 Battery charge level 75 %
IDE01841 Battery internal resistance 7.2 mOhm
IDE01842 Usable battery charge 30 Ah
IDE01843 Battery voltage at rest 12.5 V
IDE07681-MAS06086 Battery total charging throughput-Total re-charge 2188.8 Ah
IDE07681-MAS06087 Battery total charging throughput-Entire energy throughput 2344.7 Ah

[RUM4MO]

My wife's 2015 6C VW Polo 1.2TSI 110PS, at almost 8 years old and almost 45,000miles, its EFB is still okay, I'll check its stats when I service it in a week or two.

[Johntheo1]

Very good, your "spare" battery will probably be knackered, despite the smart charging, by the time replacement time comes around

[Johntheo1]

This Link might be worth a read. Uses a completely different battert "life" of 10,000 KWH.

https://www.audiworld.com/forums/q5-sq5 ... 740/page4/

[RUM4MO]

My "problem" with the original EFB in the 2015 Polo is that DIDN'T check/log/photograph all the original battery stats BEFORE I recoded that battery to get it to jump back into more usual life, a few years ago, a pity really, but such is life.

The Bosch AGM "next size up" battery that is still "resting" does seem to hold its charge very well and using my CTEK battery tester/analyser it does seem to be near enough the same open circuit CCA as it was when new and newly "topped up", though it does get connected to the CTEK charger once every few months.

My older daughter's 2019 SEAT Leon Cupra with its EFB that is the same capacity as that Bosch AGM I bought for the Polo, is definitely dropping off in CCA and I should probably get her to buy a new "next size down" AGM for the Polo, and swop over AGM batteries, doing that should avoid her facing a "no start" in the winter mornings AND avoid me having to put into use the new - longer battery tray and insulator blanket that I originally bought for the Polo - to suit that "next size up" AGM battery.

One thing that I've noticed is, and remember that I have a plug in 12V DVM in the "ciggy socket", if I drive very sensibly and get extremely good MPG figures, the battery is always in a lower but "acceptable" state of charge - ie auto Stop/Start is normally not available, but if I drive normally, the battery is always in a high state of charge from early on in a journey and the MPG is slightly lower and auto Stop/Start is available within about a mile. I'd doubt if most people are aware of this being the case - I only know this as I have that plug in 12V DVM in the ciggy lighter.

I've carried out coding in new batteries on a couple of VW Group cars - both Audis and both after fitting an aftermarket AGM battery, I worried a lot about doing that but in the end it was very easy even in my 2011 Audi S4 which has the older version of doing that within the controller - same one as on that linked article. Plus these newer cars are much more straight forward to do that on.

[grazuncle2]

One thing that I've noticed is, and remember that I have a plug in 12V DVM in the "ciggy socket", if I drive very sensibly and get extremely good MPG figures, the battery is always in a lower but "acceptable" state of charge - ie auto Stop/Start is normally not available, but if I drive normally, the battery is always in a high state of charge from early on in a journey and the MPG is slightly lower and auto Stop/Start is available within about a mile. I'd doubt if most people are aware of this being the case - I only know this as I have that plug in 12V DVM in the ciggy lighter.

I have a very similar experience to this.. I replaced a good (I think) battery for a new EFB based on this 12 DVM reading. After the new battery i was getting the same charging scenario as you. Some time later I decided to test the 12v socket supply with my recently acquired 'expensive' calibrated meter and, although the Voltage was lower as you mentioned, I noticed that the DVM was under reporting the voltage by .2v After a local run, garaging it and ignition on the next day DVM reading in cigarette socket would start off at 12.6 and settle down to 12.1v before starting up.

In reality it was 12.8 settling down to 12.3
My OBDEleven app reports higher battery voltage state too (I disassembled the Plug in DVM and tried to alter the trim dial inside but it was already at the highest you could go.. no upward calibration possible.

On start-up you can get anything up to 14v charging locally but on a higher rev drive the voltage state is generally higher and upon putting on ignition next day it would stay higher after surface voltage dissipated - higher than the usual economy run figures.

One thing I am planning on doing is to bypass the ciggy DVM and run some leads temporarily directly from the battery to the my meter inside the car and see what is actually happening at the battery when driving.. I have some sneaking suspicion that the car manages voltage to accessory outlets and I may not be seeing the whole picture of charging

[RUM4MO]

Yes I agree that there is some disparity between what you can measure at the ciggy lighter socket and what is measured across the battery under the same conditions. I only use this plug in 12V DVM as an indicator of what is going on, so uncertainty of measurement, while normally very important is not relevant to me when using that DVM.

The diagnostic port, I think, has a permanent feed from a fused source that "sees" battery voltage - but that would mean buying a suitable socket - which would probably invade the space required for your legs while driving, so maybe ignore suggestion!

[grazuncle2]

:

I'm still interested in monitoring directly.

I'll give it some thought first.

On the positive terminal there are so many cables coming off it.. battery status is obviously one of them.

Nothing is simple anymore.. i remember changing ignition points on my mini.. seeing the dwell angle etc..i thought that was complex at the time...

Then.....

[RUM4MO]

I didn't stay on "cars with points" long enough to get round to buying a "dwell angle" measuring device, I feel a bit cheated for missing out on that!!

I also feel cheated on not needing to buy one of these fancy tappet adjusting tools - Fords changed to having "stiff bolts" and then quickly to OHC, again, robbed/denied/cheated!!

Edit:- maybe the fancy tappet tool was SPQR, now Gunsons CLIK-ADJUST.

[grazuncle2]

literally laughed out loud and nearly spit coffee over the keyboard

Used Dwell angle on the garage stuff.. had no idea it existed till then.. I remember cleaning the ignition contacts regularly and then electronic ignition came out as an add-on and saw that problem disappear except the cam wear on the contact set.. Wow you took me back 60 years there

Aaah Tappets.. feeler gauge ok till the tappet surface pitted over the valve stem.. your proper adjuster brand took me back but never got to try one out .. aka Cheated

still smiling

[Johntheo1]

You are looking at history below, a 55 year old timing bulb that I used on literally dozens of cars and still use it to set up the static timing on some of my daft friends ancient cars, if you set up the static timing correctly as per the manual then you can forget about the dwell angle as long as the points gap is correct.

However, back to the future, took a few readings with the VCDS and my M.meter with engine idling both with no electical load and my max electrical load of head lights+HRS+fanspeed4. Its fairly obvious that the VCDS battery voltage IDE1834 corresponds pretty well with the battery terminal voltage but terminal 30, IDE00019, does not, especially when under load, probably to be expected as are the m.meter cabin power point readings?.

NO elec load. Idling
VCDS Battery Voltage IDE1834,13.50V. Terminal30 IDE00019,13.5V. M.meter batt.terminals, 13.46V. M.meter cabin power point, 13.46V.
"Full" elec load. Idling
VCDS Battery Voltage IDE1834,13.28V. Terminal30 IDE00019,13.15V. M.meter batt.terminals, 13.23V. M.meter cabin power point, 13.07V.

[grazuncle2]

Some science!

Thanks. So the cabin circuitry/Voltage is affected or controlled depending on need!

[Johntheo1]

I would think the voltage drop is probably due to cable resistance, my electrical full loading was probably 25 to 30A so there has to be some voltage drop between the battery terminals and terminal 30, VCDS batt volts 13.28, term 30 13.15V, a voltage drop of 0.13V or less than 1%, the cabin (M.meter) reading of 13.07V vs 13.15V is probably due to instrument accuracy, still only 0.08V or just over 0.5%, so wouldn't think there is any form of control of the cabin power point which IMO is still quite useful for monitoring voltage charging levels, obviously a voltage indication taken from the battery terminals will be 100% accurate but do you really need that.

I did notice that the charging current increased to ~ 25 to 30A for less than a minute immediately after starting (no elec load) and then fell to ~ 2.0A which makes sense as the battery drain was probably only ~ 0.3AH or so and would only require a charging rate of 30A for ~ 30 secs or so which is what occured, and at 13.5V.

[grazuncle2]

Interesting thread.. apologies for highjacking it

No I don't need a constant direct battery reading.. I'm just interested in the variance and why. The DVM plugged in in the cabin is still useful for me and I can add the .2v in my head when looking at it LOL

[Johntheo1]

I cant pick up a DVM monitor around here, can you (or anyone) send me a link to yours or similar that I can buy on line?.