Battery replacement/Coding

[x3la]

I just had my 2016 A3 battery replaced by AAA; apparently the battery was at 45%.

The MMI displayed the "Battery weak" message (after reporting that every sensor had failed and refusing to start).

After replacement I drove it a short distance to clear the Power steering, TPMS etc faults on the dash.

I attach photos of the old and new battery.

Old: Varta, 72Ah
New: AAA, 120Ah?

The old battery has a BEM code. The new battery does not (that I can see).

From what I have read on the forums so far, it appears that simply replacing the battery alone is not enough and that an update to the Energy Management system is required in order to have the battery recognised and treated as new.

If the above is true? I need to either:

1) Buy a VCDS cable
2) Take to the dealership/mechanic with appropriate equipment

Since the new AAA battery does not have a BEM code I cannot programme the exact codes into the car.

Many VCDS posts on this suggest that simply changing the serial number in the system is sufficient enough and that the entire BEM code is not important.

The "Ah" on the batteries is different. Would bumping the serial number by one digit be sufficient in this case? Are there other parameters that need changing in this instance?

If I purchase the VCDS cable, are there other things that I should do at the same time? should any 'faults' be cleared for instance?

Thanks in advance for your advice.

 

[Harvey]

If your new replacement battery was indeed a 120Ah it would be much larger than your existing and more a leisure sized battery. I would have hoped AAA have replaced like for like with the rated Ah. As you do not know the manufacturer of the new battery and not certain of the true Ah I would simply change the last digit of the serial number and leave the other settings as is. Any competent person with the correct coding tools will be able to assist you with this.

Anyone with further comments who can add to this?

 

[Fatbloke]

I think you can put in the new capacity values via VCDS.

 

[x3la]

Does RC/20Ah 120 actually mean it's a 120Ah battery though? This is the recommended battery AAA replacement for the age and model of car (see attachments).

 

[Fatbloke]

 

[bakedcorn]

Battery coding is somewhat in question. Plenty of discussions whereby it’s a stalemate if it requires coding vs it does not. Lots of good information however there is no confirmation that it is indeed required. It’s in the owners manual and so is a bunch of other information.

I had to replace my battery a few months ago and went AGM vs factory OEM and never coded it and it’s been trouble free thus far - knock on wood, lol.


Sent from my iPhone using Tapatalk

 

[Morris39]

I just had my 2016 A3 battery replaced by AAA; apparently the battery was at 45%.

The MMI displayed the "Battery weak" message (after reporting that every sensor had failed and refusing to start).

After replacement I drove it a short distance to clear the Power steering, TPMS etc faults on the dash.

I attach photos of the old and new battery.

Old: Varta, 72Ah
New: AAA, 120Ah?

The old battery has a BEM code. The new battery does not (that I can see).

From what I have read on the forums so far, it appears that simply replacing the battery alone is not enough and that an update to the Energy Management system is required in order to have the battery recognised and treated as new.

If the above is true? I need to either:

1) Buy a VCDS cable
2) Take to the dealership/mechanic with appropriate equipment

Since the new AAA battery does not have a BEM code I cannot programme the exact codes into the car.

Many VCDS posts on this suggest that simply changing the serial number in the system is sufficient enough and that the entire BEM code is not important.

The "Ah" on the batteries is different. Would bumping the serial number by one digit be sufficient in this case? Are there other parameters that need changing in this instance?

If I purchase the VCDS cable, are there other things that I should do at the same time? should any 'faults' be cleared for instance?

Thanks in advance for your advice.

Audi recommends that a new battery should be coded but this applies only if the car is equiped with an energy management function. The Ross-Tech video in a post above makes clear. Your car is so equipped (per display). My car, MY15 S3 is not equipped but I can see from a VCDS Blockmap scan what the functions would be (dummies in my car) eg calculated battery capacity, internal battery resistaence, warnings and maybe others but I don't remember.
I don't know if not coding will compromise battery life and I don't believe posters who claim they know. How could they reliably know?
As for your question about getting the scanner that depends on your outlook. An investment in $s ($200) and more importantly time to educate yourself may not be worth it unless you get some satisfaction from understading what is going on in you car and maybe avoiding unnecessay repairs.
I have found it interesting to measure base values to compare to updates as predictors of future problems, so it's a mini-hobby. BTW I don't like actual repairs as it requires a large investment in equipment/tools and education time otherwise you will bimble from fail to fail.