12v battery replacement

Audi A3 E-tron Forum

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New member
May 15, 2024
Hello all, new member but have owned a 2016 A3 Etron since 2017 - I believe I bought a car from an employee owned program , it had 5k miles, so I am pretty close to origjnal owner( now at 78K miles) Overall great car, I had the battery pack replaced (was under recall) but aside from the tires, all original parts; including brake pads and 12v battery. Which brings me to this forum. The 12v battery is on its last legs and it pains me to think I have to pay Audi to program the car to accept the new battery. If I add the cost of what Audi charges for the battery, it'll cost over $400 to change a battery? That sounds absurd to me. Does anyone know what happens if you buy a compatible battery from a big box store and NOT re-program the car?
I think you can do this yourself. There is a video on YouTube showing the removal and install of the 12 volt battery. It is a Sealed AGM? Standard battery. Hardest part is the 12 fasteners to get at the Battery!
Look here --- Audi A3 Etron Battery DIY YouTube Bryan A Aug 19, 2020
The trick is getting a tool - like the OBD ELEVEN dongal with the software to Tell the Car what battery type you have installed. The Software to reset the Battery - Coding it to the car system is required for the auto Start / Stop system. It also resets the Date of the install because apparently the car monitors Battery age and adjust for degradation. In the video he uses a VCDS program with a Laptop.
The OBD ELEVEN is a less expensive option & works with a tablet or Smartphone. I have used it to replace the battery in my 2017 Golf Alltrack. This device will identify Fault Codes in the A3 E-tron -and you can modify some features in the E-tron for little cost.
Same procedure using "Adaptation". Sold direct from obdeleven.com or Amazon. As I understand ir... The VCDS has greater capabilities if you plan to make mods to the car or need more complex problem evaluations.
Hope this helps.
It may not throw codes right away, but it will eventually. I had this issue and coded the type of battery that was installed and solved the issue.