Replacing main car battery might require CAN-Gateway coding

[fabdavrav]

Just a heads up as I found the following four channels under the [CAN Gateway 19], [Adaptions-10] using VCDS. 

 

(1)-Battery adaptation-Rated battery capacity,59 Ah
(2)-Battery adaptation-Battery technology,EFB
(3)-Battery adaptation-Battery manufacturer,JCB
(4)-Battery adaptation-Battery Serial Number,1111111111

 

This threw me a bit as I had replaced the original factory one (59Ah, EFB, Moll) with a 70Ah, AGM, Bosch, about 6 months ago, & never had any fault codes etc, so wondered if it caused any problems, as never knew about recoding for battery replacement!

 

Anyway raised this on the Ross-Tech forum & the very helpful lot there informed me that the car needs to know how much battery it has to play with for the stop/start & the SOC display etc. In my case it still thinks it has a small battery & the difference between the EFB & AGM is not much from a charger point of view, so all ok then.

 

However as of yet VCDS does not allow full changing of the manufacture code or serial number. Currently this tech has been on big Audis for ages, down to A4 size, now A3 size & loads of googling brings up threads where VCDS does allow full changing of manufacturer codes (eg VA0 is for Varta) & inputting the serial number from the side of the new battery. Ross-Tech are working on a fix for this as the new coding etc on the MQB platform has loads of new stuff.

 

Anyway worst case that I have found (whilst googling), is if your current battery keeps throwing up "low battery" warnings etc & you swap the battery for new one it might not learn the new battery so might keep throwing up the same codes, unless you go to the dealership to get them to re-code.

[decuk]

Can't think of a reason to change the battery on a car with warranty. Normally an original manufacturers unit lasts 5-6 years anyway

[fabdavrav]

Can't think of a reason to change the battery on a car with warranty. Normally an original manufacturers unit lasts 5-6 years anyway

 

Easy, VWUK & SUK skimp on the Ah size rating.................loads of people are having MK7 Golfs with flat batteries after 18 months, MK3 Octavia when it hits 18 months will start showing the same Low battery warnings, & they are seen as "consumables" so not fully covered!!

 

Basically the fully electric steering, Stop/start functions, individual injectors, individual coils, put heavy loads, let alone the electric coolant pumps, heated seats, sat navs, xenons, climate controls, etc, etc......I had a 59Ah in my new MK7 Golf which is about the same in my old MK1 Fabia with less demand!!!

 

Oh & the Golf in UK has EPB, which you don't get, the EPB basically eats electricity

Edited 5 May, 2015 by fabdavrav

[Orville]

The car will only measure battery voltage, with 12.6V being fully charged and 12V being rated as close to empty. Whether the battery is 59 Ah or 70 Ah, or made by Tom, **** or Harry should not make any difference so long as voltages remain within tolerance. Any batteries kicking up low battery warnings or failing to activate Stop-Start will do so because the battery has dropped below a set threshold.

 

Batteries can have different discharge characteristics (as with mobile phone batteries). Some may hold close to 12.6V until they are 50% discharged whilst others will drop to 12.4V at 50% yet still have as much remaining capacity.

 

Theoretical Example

Battery #1 59 Ah

Voltage, Charge, Remaining Capacity

12.6V 100% - 59 Ah

12.5V 50% - 29.5 Ah

12.4V 30% - 17.7Ah

12.3V 20% - 11.8 Ah

12.2V 15% - 8.9 Ah

12.1V 10% - 5.9  Ah

 

Battery #2 70 Ah

Voltage, Charge, Remaining Capacity

12.6V 100% - 70Ah

12.5V 80% - 56 Ah

12.4V 60% - 42 Ah

12.3V 40% - 28 Ah

12.2V 25% -  17.5 Ah

12.1V 10% - 7 Ah

 

If for example VAG set Start-Stop to stop activating at 12.4V then the battery with 59 Ah may appear to perform better than a 70 Ah battery. It depends how the battery has been designed and upon it's internal resistance. The above theorectical example shows battery #1 will continue operating Stop-Start until only 30% or 17.7 Ah capacity remains whilst battery #2 will stop at 60% or 42 Ah remaining capacity. Battery #2 will actually continue running for MUCH longer but at a lower nominal voltage, making the car believe that it is running low.

 

If non-OEM batteries are kicking up lots of low-battery alarms it will likely be because they have higher internal resistance so cannot maintain higher voltages for as long. This does not mean they run flat faster, but it can appear this way to the car.

Edited 5 May, 2015 by Orville

[decuk]

Oh! Well I did ask I suppose. I'll worry about it if it happens

[Neily03]

MK3 Octavia when it hits 18 months will start showing the same Low battery warnings

It's well well passed that, how may reports on here of battery troubles??.....

[Richf]

Can't think of a reason to change the battery on a car with warranty. Normally an original manufacturers unit lasts 5-6 years anyway

Batteries arent covered under warranty , our mk2 Octy lasted 3 years and our Superb went through two new batteries in 6 years !

[neiln]

59 AmpHour would have been plenty for up to a 2 litre petrol, or probably about a 1.8 diesel ( less sure on oil burners).  These days though, with stop start and with more convenience consumers.... Tighter but I'd not expect trouble for a good while.   Batteries are generally pretty good these days

[fabdavrav]

Go google Audi A8 or just Audi & coding replacement batteries with VCDS, & you will see the problems/faults, also OEM factory batteries have been "failing" not just so called rubbish aftermarket.........infact my aftermarket is a Bosch AGM made by Varta, so the top end where as VW fit a cheapo EFB made by Moll............& that's direct Factory fit!!!

 

 

Loads of topics on it, just now this coding requirement is now on the MQB chassis so more people will become aware of it............................

[Bindinbear]

My mk5 golf edn 30 battery was still original after 6 yrs, lots of drain inc xenons, nav, short stop start journeys etc. no issues

[Gabbo]

I gues this makes sense when you change the size of the battery.

Cars have very complex state of charge algorithms for looking after the batteries these days, like periodic discharging, slow charging, fast charging which depend on lots of factors.

 

As stated by Orville, if the car doesn't know there is a different battery fitted the way it controls the charging & detects the voltage thesholds will be wrong.

The next question is whether changing the values will make any difference.

If the larger batteries are not a standard option for the O3 these modified setting might not actually make any difference.

 

I've never had a change a battery on any of my cars (last Mondeo was 7 years old). I hope I dont have to on the O3.

 

I don't know how much the "accesories" & loads really affect the battery anyway because when the engine is running the main load will be fulfilled by the alternator.

Stop/Start perhaps because it greatly increases the number of starts & time running the electrics from the battery.

But I'd imagine a hot start is much more gentle on the battery than the first start each morning anyway.

[fabdavrav]

Ok lets start again................

 

The battery tray in engine bay will accept a 096 case size which in an AGM type is 70Ah, this is the biggest the car will take. VAG fit the smallest they can get away with & you will notice that the clamp has three positions, the smallest being very poky!

 

You may never have any problems with your OEM battery for 6yrs, but if you do & you have to replace the battery for any reason then those four lines of code need to be altered.

 

Even if you get the same AH, size, make etc, you need to alter the serial number channel to show that a new battery has been installed so that the ECU can work from the new base line.

 

As for swapping to a bigger one, I personally found on this car & my previous cars that a bigger battery has made the start up more "instantaneous" ,

 

The high loads on my car:- electric coolant pump, four fuel injectors, four ignition coils, electric steering, heated seats, heated front screen, dual zone climate, Dynaudio sound, Xenons, sat-nav,  

 

Why AGM, well it has 3 times the starts compared to standard & EFB 2 times the cycle starts compared to standard batteries. AGM is totally leak proof & the safest in a crash, even if the casing is broken, or the battery is upside down!

 

Oh & all cars that have stop/start have to have either EFB or AGM batteries.

[Orville]

There are just two connections/terminals on ALL car batteries. These are "+" and "-" (12v & earth). The only reading which can be taken by the cars management systems is Voltage. You can call the battery whatever you like or rate it at 59, 70 or 500 Ah, but the car can only measure the Voltage. So long as measured Voltage is good it does not matter whether only 10 Ah or 100 Ah of capacity remains because there is no way of measuring it.

Before electronic management systems people could tell when their batteries were running very low because the starter would turn slowly or lights would dim (usually at a point well below 12V). Nowadays cars measure actual voltage and will inform us when voltages drop close to 12V, and perhaps even attempt to preserve the battery by turning off auxiliary systems. The cars alternators will charge a battery up to 12.6V and then stop charging until it drops below this level.

[fabdavrav]

There are just two connections/terminals on ALL car batteries. These are "+" and "-" (12v & earth). The only reading which can be taken by the cars management systems is Voltage. You can call the battery whatever you like or rate it at 59, 70 or 500 Ah, but the car can only measure the Voltage. So long as measured Voltage is good it does not matter whether only 10 Ah or 100 Ah of capacity remains because there is no way of measuring it.

 

 

On stop/start systems there are ECU connections to the battery - terminal, & you can't jump/charge direct of the battery - you have to go to the bodywork point. The cars ECU has the SOC display which is capacity so it has to be told the full intial capacity to then work from.

 

So any 12V battery will be good then by your reasoning??..................I'd like to see that, do you realise it takes at least 30 mins drive to do about a 20% charge to the battery from the alternator?............capacity is required to absorb high spike demands like switching on the front & rear heated windows & heated seats at the same time.......................

[Richf]

The larger the AH of the battery the longer it takes to discharge or recharge , I suspect that is why the car needs to know there will no doubt be various protocols written in light of this

[mannyo]

My Audi has battery management and the module requires recoding every time the battery is changed. My Audi has the usual + and - leads, but in addition also has an additional wire which it uses to measure voltage and current draw.

 

Over a period of time the module learns how the battery is charging/discharging, current charge state, temperature and the number of deep discharges completed. Recoding the module causes these learnt values to be reset to new values and the learning process starts again.

 

The only important value that must be altered is the CCA, if you replace the battery like for like, then simply altering the serial number by one will reset all the stored data.

 

The battery module does far more than monitor volts, it can shutdown systems as the battery starts to run flat (eg. Kessy) and in the case of my Audi it also regulates the charge from the alternator, so it will rapid charge and then switch to trickle charge when the battery is full.

[fabdavrav]

My Audi has battery management and the module requires recoding every time the battery is changed. My Audi has the usual + and - leads, but in addition also has an additional wire which it uses to measure voltage and current draw.

 

Over a period of time the module learns how the battery is charging/discharging, current charge state, temperature and the number of deep discharges completed. Recoding the module causes these learnt values to be reset to new values and the learning process starts again.

 

The only important value that must be altered is the CCA, if you replace the battery like for like, then simply altering the serial number by one will reset all the stored data.

 

The battery module does far more than monitor volts, it can shutdown systems as the battery starts to run flat (eg. Kessy) and in the case of my Audi it also regulates the charge from the alternator, so it will rapid charge and then switch to trickle charge when the battery is full.

 

As I stated earlier this tech was on the big Audis for ages & has now filtered down to "small cars" like the Golf & Octavia. I agree with all you state which is why I started this thread as a heads up, unfortunately some people think a battery is  just a + - connections & that's all the car needs to know!

 

oh well .............if & when they have problems don't come crying........ 

[Orville]

The stock battery within my VRS TSI is a 69 Ah Varta EFB.

 

 

The battery itself is dumb, but the car can estimate state of charge by logging voltage (and possibly current draw) over a period of time. By doing this it can potentially build a picture of long-term performance, and estimate when the battery is approaching end of life.The final determination of whether a battery is running low will be realised by the actual battery output voltage.

 

Recoding the battery will reset old data and allow the EMS to create an accurate profile for the new battery. Unfortunately non-OEM are unlikely to be listed, so selection of an equivelent supported battery will be needed instead.

 

Using the above battery spec may be better when installing a non-OEM 70 Ah battery than keeping 59 Ah data, but you'll still get a low battery warning when volts drop below a set threshold.

Edited 6 May, 2015 by Orville

[fabdavrav]

 

The battery itself is dumb,.

 

. Unfortunately non-OEM are unlikely to be listed, so selection of an equivelent supported battery will be needed instead.

 

 

 

Yep, just the car logs all kinds of info as has been explained.

 

No, on the worked out coding at least 6 of the main makes are listed on the drop down menu, along with 12 different battery types, & you can input any Ah number you wish as type in & not from drop down.

 

obviously not had a play with VCDS have you???...................

[Orville]

Yep, just the car logs all kinds of info as has been explained.

 

No, on the worked out coding at least 6 of the main makes are listed on the drop down menu, along with 12 different battery types, & you can input any Ah number you wish as type in & not from drop down.

 

obviously not had a play with VCDS have you???...................

I have never played with VCDS so have no idea what options are available. However, my expertise is electrical engineering and I understand battery design.

[fabdavrav]

Right then just for the non-believers........

 

I plugged in VCDS to my MK7 Golf which will use the same modules as the MK3 Octavia, & had a look at [CAN Gateway-19],

 

Firstly the current (not correctly decoded) list of battery types in the VW coding for the MK7 Golf under [CAN Gateway-19], [Adaptions-10]

 

 

This is the correct coding for the battery brand names from the Ross-Tech site, just the new UDS stuff in the MK7 is causing incorrect data display until the next release.

 

 

Then looking briefly under the  [CAN Gateway-19], [Advanced measuring values] one can see lots of real time data.

 

 

 

I started this thread because I know & use VCDS, & wanted to pass on info which is relevant to the MQB platform cars. The tech which is in these cars has been used on the expensive Audis like the A8, Q7, A6 etc for many years, just it is now standard fit on "cheaper" cars. 

 

Gone are the days of just fitting any old battery & that's it all ok......if you still believe it more FOOL YOU....

 

YOU HAVE BEEN WARNED!!!..............

[Breezy_Pete]

There are just two connections/terminals on ALL car batteries. These are "+" and "-" (12v & earth). The only reading which can be taken by the cars management systems is Voltage. You can call the battery whatever you like or rate it at 59, 70 or 500 Ah, but the car can only measure the Voltage. So long as measured Voltage is good it does not matter whether only 10 Ah or 100 Ah of capacity remains because there is no way of measuring it.

Before electronic management systems people could tell when their batteries were running very low because the starter would turn slowly or lights would dim (usually at a point well below 12V). Nowadays cars measure actual voltage and will inform us when voltages drop close to 12V, and perhaps even attempt to preserve the battery by turning off auxiliary systems. The cars alternators will charge a battery up to 12.6V and then stop charging until it drops below this level.

I'm not sure I agree with that bit I've bolded.

 

State of charge for a lead acid battery is well predicted by terminal voltage at rest.  So 12.6ishV is a 'full' battery, 12.0ishV a virtually empty one.  If the car's brains know what the (design) battery capacity is it can work out how many amp-hours of charge remain available for any point it measures in between these extremes. Admittedly it's not easy to measure this 'at rest' voltage when the engine is running, because the alternator is pushing the terminal voltage up as much as it can/needs to, so that the battery will charge. But every time the engine is switched off, the ECU in question can soon work out the state of charge by how fast, and how far the terminal voltage falls.

 

If the voltage falls to 12.3 for example, on a 60Ah battery, that might suggest about 50% of 60,  or 30Ah available. For an 80Ah battery, that might be 40Ah.

[fabdavrav]

I'm not sure I agree with that bit I've bolded.

 

State of charge for a lead acid battery is well predicted by terminal voltage at rest.  So 12.6ishV is a 'full' battery, 12.0ishV a virtually empty one.  If the car's brains know what the (design) battery capacity is it can work out how many amp-hours of charge remain available for any point it measures in between these extremes. Admittedly it's not easy to measure this 'at rest' voltage when the engine is running, because the alternator is pushing the terminal voltage up as much as it can/needs to, so that the battery will charge. But every time the engine is switched off, the ECU in question can soon work out the state of charge by how fast, and how far the terminal voltage falls.

 

 

Did you click on my pics above to bring up a full screen version?................They are of the some of the measuring blocks in my MK7 Golf's CAN Gateway as seen on VCDS..................basically shows & backs up what you are talking about.................

[Breezy_Pete]

No, I didn't: damn these cars are clever! Looks like all sorts of parameters are continuously being measured including current flow.

[J306TD]

Does this really need to be altered if you fit a bigger battery?

Sent from my Galaxy S5