I have a 2018 Superb Sportline, I keep reading about battery replacement coding. The difference between getting someone like Halfords and doing it myself is around £100. I'm very capable of charging a car battery, do i have to have it coded or can i just change like for like 👍 if not why does it require a code?

Hope someone can help me!

Regards 

Bryan 😁 

It's not coding as such.  You need to use the the likes of VCDS, OBDII or Carly to let the car know a new battery ahs been installed.  The car then knows this and adjusts the charging to suit.  There are videos on YouTube about it.  If you search about it you'll find articles / people saying you don't have to do it.  Others saying you do and some saying if you don't do it it might shorten the live of the new battery.  If you have VCDS, OBDII or Carly it is easy enough to do.  You just put in the capacity of the new battery, the type of battery and it asks for the serial number.  For the serial number you can put anything as long as it is different to the existing battery.

Thank you for taking the time out to answer my question 🙏 🙂 

Worth adding, for the most part you shouldn't lose many, if any, pre-sets such as radio stations or bluetooth pairings when swapping the battery, although you may encounter some faults showing on initial start up. These can usually be fixed by taking the car for a short drive incorporating a lock-to-lock steering operation.

I somehow manged to set the alarm off when I disconnected my old battery. I had no idea how to switch it off so just pressed everything I could think might be relevant until it finally silenced. No idea how I did it.

As long as you replace the same type of battery (EFB for EFB, AGM for AGM) and the size of the battery is the same you don't really need to do the coding...

 

I change my OEM battery for a Varta of the same type 68Ah to 70Ah without coding & it's worked fine for the last few years without any issues. 

 

After replacement there were no DTCs and stop/start was immediately available. 

 

 

If you already have the tools (vcds/Carista/obd eleven et la) then you could do it. 

But on my side I didn't think it was worth it to sort out another £60 for one of these tools & subscription.

I’m literally doing mine on Saturday, battery was cheap enough but VCDS was £299 (10 car vin)

 

But as my cars getting on now and no plans of getting rid, VCDS will come handy going forward.

 

I can let you know if I lose anything but I’m only suspecting trip counter tbh, if there’s anything else it’s easy to set back up again anyway

Thank you all for the feedback, I don't have a code reader and not willing to buy one to be honest, I believe if I buy the exact same battery on specification it should ok! famous last words 🙂 I have spoken to my local garage who have looked after my vehicles and they said they would code it free of charge if I brought the vehicle round, so I think that's my way forward!  I would not have believed changing a battery would cause such confusion, bring back the days you only worried if the radio would need a code!! I have spoken to a mechanic too and they said like for like it does not require any coding.

So thank you all again for your support it's appreciated 🙂 

Regards

Bryan  

At the very minimum the serial number (BEM code, which aftermarket batteries won’t have) needs changing so the car knows it’s a new battery, but I’ll do the lot and the ah most likely 68 to 70 if you have agm

 

If you have the tools you can do it.

 

My thinking was, £60-80 for OBD11 or Carista was too much for nothing.

you can buy another battery for that price so if it last a year or two less you are no worse off.

 

I didn't change anything, stop start was available on the first drive & I think it was around 2 years ago I changed it, I've had no issues since.

 

I would hope the software in the BCM is able to recognise a new battery based on its behaviour so coding is only really needed if you change the type or significantly change the size.

5 hours ago, Gabbo said:

If you have the tools you can do it.

 

My thinking was, £60-80 for OBD11 or Carista was too much for nothing.

you can buy another battery for that price so if it last a year or two less you are no worse off.

 

I didn't change anything, stop start was available on the first drive & I think it was around 2 years ago I changed it, I've had no issues since.

 

I would hope the software in the BCM is able to recognise a new battery based on its behaviour so coding is only really needed if you change the type or significantly change the size.

Well, I fear you can still hope for a while...

 

BCM being able to do so means a specific software function for that, which consequently would require development and validation tests, to be sure it makes reliable diagnosis w/o being fooled by a simple manufacturing dispersion, for instance. This means ££££ !

Having a simple logic that checks if the P/N number has changed is a "2-line code". No development, no test, almost no £££.

Done...

 

Additionally, there's a way to set the autonomy value (how many Ah) to get a reliable power management and charging phases.

If ones install a "bigger" battery with a higher Ah value w/o adjusting this parameter, it's just money spillage, because this battery won't be charged at its full capacity, only at the original battery capacity as a maximum.

 

This may help:

 

 

6 hours ago, Danoid said:

At the very minimum the serial number (BEM code, which aftermarket batteries won’t have) needs changing so the car knows it’s a new battery, but I’ll do the lot and the ah most likely 68 to 70 if you have agm

 

A BEM code is not necessary, a new serial number can be created by simply changing the last digit of the original number.

This will serve to inform the BCM the battery has been replaced and clear any logged battery defects that may be limiting alternator charging rate.

Edited 22 January, 20251 yr by Warrior193
omission

I have a 2016 2.0 TDI since new, that's done 96k miles and I intend to keep it. However I only use it very occasionally now ( less than 4k miles in total for the last 3 years ). The battery has given up the ghost and even after fully recharging it struggles to start the car - not bad for 9 years ! If I turn off the stop/start function because the extra cost of a suitable AGM battery wouldn't pay back for the mileage I do can I fit a non stop/start rated battery 70 Ah battery and forget about coding ?

More importantly has anyone do it ?

Hello, welcome to the forum.

Is your present battery AGM - or EFB?

You should replace with at least an EFB battery - which will be less expensive than AGM (if that is what's currently fitted) - a standard lead-acid battery would probably not survive for long. Adaptation of the BEM (coding) for the new battery should still be done,

A compromise would be to fit the standard battery and disconnect the BMS module current measuring shunt lead which will disable the stop-start as you have indicated your desire to do, revert to a standard alternator charging profile and avoid the expense of BMS recoding.

The battery will last as long as it would on any standard vehicle, arguably longer than a replacement AGM on a stop-start vehicle.

It is unrealistic to expect any battery replacement to last as long as the factory fitted (Moll batteries aside) one even if it appears to be the identical make and capacity.