I bought the BavarianTechnic cable, so that I can do basic activiations, read codes, troubleshoot, and yes - register new batteries. Cost a few hundred bucks, but now I can do a lot of things in my garage that would normally be done at the dealership.
I replaced my battery with a new one from Autozone two days ago. I was able to register it myself in a matter of seconds.
Having the BT cable also allows me to set my own service intervals for oil changes (7,500 miles instead of 15,000), reset the brakes, and do quite a few other things. I think it's a worthy investment, seeing how one trip to the dealer for some of these basic functions pays for itself.
BMW Ergo Zoom
IMHO: E39 < E60 > F10
2011 F10 535xi (ED July 15, 2011)
2008 E60 550i (ED July 22, 2008)
2000 E39 540i (Retired)
Member BMWCCA #402733