So I suspect my MkIII has the original battery (over 3 years old), no battery low warnings are appearing yet, but with the ignition on it is dropping to 12.2v. I am thinking it is not far off karking and would rather preemptively get it replaced rather than have the Mrs stranded, as she drives it mostly.

 

When it has been fully charged and left over night it will settle down to about 12.6-7v.

-Fully charged dormant: 12.6-7v

-Doors open 12.4v

-Ignition on 12.2v

Workshop manual indicates 12.5v min is required.

 

Currently has an AGM, 70Ah, 760CCA battery installed with 'Start Stop technology'.

I have permanently disabled S/S, does the replacement still require S/S features?

Am I safe to just get an AGM with specs of 70Ah & 760CCA? I am in a warm environment.

 

Cheers

 

 

Can't go wrong with like for like. Disabling s/s just means you cycle it less and should last longer. These big batteries are not cheap. 

I am still on the original battery after more than 4 years (Sept 2015), and I use stop-start. You might get another year out of yours.

Is the car likely to warn about the SOC when it's gets even lower? It warns about everything else so assume there must be some sort of BMS?

On 12/11/2019 at 02:00, Anquetil said:

Workshop manual indicates 12.5v min is required.

Does it state that number with ignition on?

The dormant voltage suggests to me that everything is absolutely fine with your battery.

 

9 minutes ago, Anquetil said:

Is the car likely to warn about the SOC when it's gets even lower? It warns about everything else so assume there must be some sort of BMS?

I don't know for sure but expect there would be a warning. There is a battery management system which stops the stop-start from cutting in if the battery is low, although I see you have disabled s-s. You could have the battery checked at a local fast fit or similar.

 

46 minutes ago, Anquetil said:

Is the car likely to warn about the SOC when it's gets even lower? It warns about everything else so assume there must be some sort of BMS?

`SOC`?

`BMS`?

2 minutes ago, mandp said:

`SOC`?

`BMS`?

State Of Charge

Battery Management System 

9 hours ago, OldBoyScout said:

I don't know for sure but expect there would be a warning. There is a battery management system which stops the stop-start from cutting in if the battery is low, although I see you have disabled s-s. You could have the battery checked at a local fast fit or similar.

 

Absolutely true !

The S&S start limit voltage is set to 7,6V as a default value. This can be tuned with VCDS. For instance setting this value to 12,0V disables de the S&S permanently.  

Three years seems really short life for a modern battery - I would expect 5-7 years as a norm.

I haven't replaced a battery in my last 3 cars at 5years old, 6 years old and 8 years old.

The 5 year old was also a stop/start AGM battery and was showing no signs of deterioration when I sold it.

2.8 No-load voltage measurement - Demonstration vehicles and stock vehicles

 

Note
♦ No-load voltage measurement on demonstration and stock
vehicles must only be carried out within the prescribed main‐
tenance procedures as a criterion for evaluating the battery
state.
♦ The no-load voltage measurement serves to determine wheth‐
er the batteries of demonstration and stock vehicles should be
charged.
♦ The battery must not be drained by any electrical equipment
for at least 2 hours before the measurement is taken.
 

Follow the procedure described below for measuring the battery
voltage in the no-load state:
– Use the hand-held multimeter to measure the battery voltage.
The battery no-load voltage must not fall below 12.5 V.
If the hand-held multimeter indicates 12.5 V or more, the battery
voltage is O.K.
If the hand-held multimeter a battery voltage of less than 12.5 V: – Charge battery 
After charging wait at least 2 hours during which the battery with
electrical components must not be subjected to any load or
charge:
– Use the hand-held multimeter to measure the battery voltage.
The battery no-load voltage must not fall below 12.5 V.

 

So it seems my battery is ok for now, but certainly nearing end of life in this vehicle.

My 'no-load' voltage after charging and sitting is around 12.6-7v.

 

9 hours ago, Anquetil said:

but certainly nearing end of life in this vehicle

 

Based on what?

 

9 hours ago, Anquetil said:

2.8 No-load voltage measurement - Demonstration vehicles and stock vehicles

 

Note
♦ No-load voltage measurement on demonstration and stock
vehicles must only be carried out within the prescribed main‐
tenance procedures as a criterion for evaluating the battery
state.
♦ The no-load voltage measurement serves to determine wheth‐
er the batteries of demonstration and stock vehicles should be
charged.
♦ The battery must not be drained by any electrical equipment
for at least 2 hours before the measurement is taken.
 

Follow the procedure described below for measuring the battery
voltage in the no-load state:
– Use the hand-held multimeter to measure the battery voltage.
The battery no-load voltage must not fall below 12.5 V.
If the hand-held multimeter indicates 12.5 V or more, the battery
voltage is O.K.
If the hand-held multimeter a battery voltage of less than 12.5 V: – Charge battery 
After charging wait at least 2 hours during which the battery with
electrical components must not be subjected to any load or
charge:
– Use the hand-held multimeter to measure the battery voltage.
The battery no-load voltage must not fall below 12.5 V.

 

So it seems my battery is ok for now, but certainly nearing end of life in this vehicle.

My 'no-load' voltage after charging and sitting is around 12.6-7v.

 

This is the correct table for agm batteries, so at 12.6-7 your battery is fine, remembering that your car BMS  will not charge to 100% to allow for regenerative/ overrun charging.

 

On 12/11/2019 at 12:00, Anquetil said:

So I suspect my MkIII has the original battery (over 3 years old), no battery low warnings are appearing yet, but with the ignition on it is dropping to 12.2v. I am thinking it is not far off karking and would rather preemptively get it replaced rather than have the Mrs stranded, as she drives it mostly.

 

When it has been fully charged and left over night it will settle down to about 12.6-7v.

-Fully charged dormant: 12.6-7v

-Doors open 12.4v

-Ignition on 12.2v

Workshop manual indicates 12.5v min is required.

 

Currently has an AGM, 70Ah, 760CCA battery installed with 'Start Stop technology'.

I have permanently disabled S/S, does the replacement still require S/S features?

Am I safe to just get an AGM with specs of 70Ah & 760CCA? I am in a warm environment.

 

Cheers

 

 

 

Hi mate, I am assuming your is a 140TDI? As most (if not all) petrol's have EFB batteries.

Suprised you have an AGM.

Could it have already been replaced?

OP did say he lives in a warm place. Heat kill batteries. In tropical weather, car batteries normally won't last past year 3. 

4 hours ago, KeteCantek said:

OP did say he lives in a warm place. Heat kill batteries. In tropical weather, car batteries normally won't last past year 3. 

Well that I didn't know.

So cold weather reduces the battery's ability to hold a charge and hot weather kills them early.

 

C'mon Mr. Musk - invent us a battery that works better....

Voltage log... maybe of interest.

You will see below a voltage log of my 2016 MY17 Superb (190) taken on a 250 mile trip on mainly motorway. About four stops in the journey, weather dry, temperature about 40f, average speed about 60mph.
This was taken when the car was about six months old, factory fitted battery Varta AGM.

Thanks for these graphs/tables, my thinking was a little old and applicable to Lead Acid battery - when I see 12.3v and below I worry. I hadn't realised the differences in battery tech, so it would seem my battery is perfectly fine and displaying similar voltages to DCC's above.

My Skoda Superb has about 8000km and the battery concerns me. I have seen it as low as 11.4v. I have charged it and the following day (yesterday) after driving about 60km it was on 12.2v. Today it is on  12.11v (doors closed and everything off) and I haven't driven it. Should I be concerned? I have ordered one of these monitors https://www.ebay.com.au/itm/Car-BM2-Battery-Analyzer-12V-Bluetooth-4-0-Load-Charging-Electric-Circuit-Tester/133248875104?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3D465c2fc700034731afa243e00a7ece56%26pid%3D100005%26rk%3D6%26rkt%3D12%26mehot%3Dco%26sd%3D232763818295%26itm%3D133248875104%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851 

 

The battery is a "Banner BA2" EFB (Austrian).

5 minutes ago, GWCTas said:

My Skoda Superb has about 8000km and the battery concerns me. I have seen it as low as 11.4v. I have charged it and the following day (yesterday) after driving about 60km it was on 12.2v. Today it is on  12.11v (doors closed and everything off) and I haven't driven it. Should I be concerned? I have ordered one of these monitors https://www.ebay.com.au/itm/Car-BM2-Battery-Analyzer-12V-Bluetooth-4-0-Load-Charging-Electric-Circuit-Tester/133248875104?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3D465c2fc700034731afa243e00a7ece56%26pid%3D100005%26rk%3D6%26rkt%3D12%26mehot%3Dco%26sd%3D232763818295%26itm%3D133248875104%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851 

 

The battery is a "Banner BA2" EFB (Austrian).

 

Are you using a Multi-meter to measure or an OBDeleven?

 

1 minute ago, ope126 said:

 

Are you using a Multi-meter to measure or an OBDeleven?

 

 

Multimeter @ope126

I have a March 2017 Superb estate Petrol 280 4x4. Only 23000 miles but has let me down a couple of times recently. It does give you a warning that the 12v voltage is low but in my experience it then won’t start!

 

Had it checked but the specialist was not sure if OK or not. Had 7 BMWs on the trot and they have all lasted 8+ years so 4 does not seem good. I am told the type of battery it use requires programming which costs extra on top of a hefty battery price. 
 

I am going to visit my local specialist when they have the model in stock as they are like hens teeth. They will check my alternator before replacing the battery. 

Hold on, before you do anything..  ...

 

It needs a good recharge to 100% with a decent charger before you condemn it. Many low battery issues result from low useage and the car's battery management state of charge calculation getting out of whack with the true state of charge. (Micro hybrid system see below)

 

Needs charging for a minimum of 24 hrs, preferably longer and watch out how you connect the charger. As per Skoda user manual, the negative charger lead must go to the chassis tab and not directly to the battery post.

 

Unlikely that anyone can check the alternator as these are smart alternators controlled by the battery management and give out a variety of voltage outputs depending on its algorithm which will only confuse someone checking with a voltmeter and likely to tell you its broken when it isnt. Alternators rarely fail nowadays.

 

A new battery needs "coding" in which requires an appropriate diagnostic tool,  to inform the battery manager that a new fresh battery has been fitted (change the serial no), whether its an EFB or AGM (setting=fleece) battery and its rated capacity (Ah).

 

https://www.yuasa.co.uk/info/technical/micro-hybrid-hybrid-vehicles-explained/

 

A good supplier of batteries at reasonable prices is tanya.co.uk they do a massive range.

 

Others can probably give you recommendations as to preferred make, capacity, model, EFB/AGM technology.

 

To extend the life of batteries in cars like the Superb that use start/stop (micro hybrid) technology, its highly recommended to attach a decent smart charger from time to time to top up the battery fully. Normally these batteries will sit at only 70-80% state of charge (SOC) because of the way the battery management and recuperation works, over time SOC will go even lower as the battery monitoring has limitations, it cannot, for example, track self discharge which gets worse over time. Eventually this increasingly lower SOC kills the battery prematurely if allowed to persist for too long due to irreversible sulphation.

 

Edited 16 April, 20215 yr by xman

Thank you very much for such comprehensive advice. I am in the process of charging but have used the negative terminal so hopefully I have not done any long term damage. Charging for more than 18 hours is impossible currently but does it have to be continuous?

 

I have a Sealey charger with a reconditioning mode. Do you think that is worth a try!

CORRECTION

 

The charger has been connected correctly.