Wait, you must be assuming that you're flying at night, because that extra two minutes you get in the day is very important to know. . . I mean, my first reaction to a total electrical failure is start the battery clock no? Er. . . wait . . . that's not a bold face item there . . .Very, very sarcastic - the battery in the 60 also exists to start the APU. Also gives you "9 minutes" of power for the backup attitude indicator and radio if you lose absolutely everything.