The battery is failing in my 2013 328xi. If I replace it with an identical BMW battery is it necessary to register the new battery and if so why? There are answers on both sides of this question online. The only reason that I can imagine this must be done would be if they do actually adjust the charging rate as the battery ages. Some have been told this is the case by techs, others have been told that registration is only required if the CCA and AH of the battery change (also by techs). It is very expensive (at least at BMW dealer shops) and it seems unlikely to me that battery cost savings (without reregistering costs) would justify the cost of registering. Would really like some explanation of what is required a d why.