Just took my Sig Model S to service center for pano glass panel replacement due to small road hazard crack. They told me 12volt battery needed to be replaced, OK with me. Have about 10K miles on car, always worked good and no charging problems. Got home, now get red ring of death when try to charge, says needs service and 12v battery low and car may stop operating. Does this mean I need to get car towed? Obviously service problem, did not realize that 12v battery tied to charging. Called service but waiting for answer. Edit: Never Mind. Tesla Service was able to reset 12v service remotely from California, now charges fine. Their technology is pretty impressive.