I understand that EFB and AGM car batteries, used in start/stop vehicles, need some kind of registration or programming when they are replaced.

  • Is this always the case? Can you skip this step if you replace the battery with an identical one?
  • How does this step work and how much does it change from car to car? (I have a Volkswagen). Does it mean pushing some buttons? Does it require connecting a laptop to the car?
  • Is it something that any mechanic could do or something that only an authorised dealer can do, e.g. maybe because there is some kind of software encryption and only authorized dealers can do it?
  • In my area, authorised dealers are all closed because of the lockdown, but there are mobile mechanics who can replace tires and batteries. They explicitly say they have the "kit" to program an AGM battery. Does this sound credible? Or would they do a half-baked job because, say, every manufacturer requires very different kit for this?
  • The Volkswagen manual doesn't say anything, other than "bring it to a Volkswagen dealer"; the philosophy is that even replacing the screen wash should be done by an authorised dealer who will charge for labour, otherwise very bad and dangerous things will happen! :)
  • If you want to work on your car then get something other than a VW - you seem to have this complaint about the dealers every time you post.
    – Solar Mike
    Apr 24 '20 at 13:43
  • You must have a lot of time on your hands if you always come back with these comments that add nothing to the discussion. FYI I don't want to "work on my car", I want to pay someone else to replace the car battery for me, and I just want to understand how the process works. That is not "working on my car" Apr 24 '20 at 13:48
  • These comments are not constructive on either side.
    – GdD
    Apr 24 '20 at 16:12
  • "A start-stop battery is a part of the on-board electronics and is linked to the vehicle electronics via the Battery Management System (BMS) and the battery sensor (EBS). The control unit detects the number of starts and the energy flow, monitors the state of charge and controls charging. When a start-stop battery is replaced, the energy management s system is programmed by the diagnostic device in the workshop.">>>>>>batteryworld.varta-automotive.com/en-gb/…
    – Moab
    Apr 24 '20 at 16:25
  • Also this>>>>yuasa.co.uk/info/technical/…
    – Moab
    Apr 24 '20 at 16:27

I actually found quite a few answers in this video. The guy explains that you need to input the "BEM code"; some manufacturers put a sticker with this code on the battery, but not all. This code tells the car how to properly manage the battery and is entered using a device that looks like a tablet, connected to the car.

There is also the VCDS software, which I think is a software you can install on a Windows laptop; an example is here

These videos answer how a new battery is registered to the car, but I'll confess I still haven't fully understood why it's needed and if it really has to be so convoluted. I must say it does remind me of how corporations fight the "right to repair" (google Louis Rossmann right to repair), forcing you to use only official channels for even the most banal type of repair. Yes, the videos talk about how the car must be told that there is a new battery, but is entering a specific code which not all batteries have, and entering it with a very specific tool the only feasible way to do so?

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