Battery registration and BMS resets: the step German cars punish you for skipping
Most European cars built after roughly 2008, and a growing number of Japanese, Korean and American models, run a battery management system that tracks the battery's age, capacity and charge acceptance. The alternator's charging strategy is tailored to that data: an old, tired battery gets charged harder and more often. Fit a new battery without telling the car, and the BMS keeps applying the old battery's aggressive charging profile to the new one. The result is chronic overcharging, gassing, shortened life, and on many cars a stop-start system that refuses to operate.
If you drive a Nissan Sunny or a Mitsubishi Pajero, relax: most conventional cars without intelligent charging need no coding at all, and anyone adding a coding fee to such a job is padding the invoice. When in doubt, the question to ask is specific: does this exact model and year require battery registration, yes or no.