With so many excellent ideas!! I can´t understand why see so many brand new cars on the road with low beams excessively high! The Silverado, F150 and some Korean cars are very good examples!
Also, the taillights that aren´t mandatory to be full-time ON. So many cars on the highway full dark...
For any battery:
V=Vemf-IRi
So, because of internal resistance (Ri), the batteries will totally drain for t->infinite (sometimes it is a very short infinite!)