Mako09, your suggestions are good, but I've been through all that. I already have the display set very dim, and killing off background apps had no effect at all on my problem. I have definitely isolated my particular problem to Exchange ActiveSync calendar looping. Others may have different problems, for sure, but that is my problem. It is easily demonstratable.
I have determined that I can "fix" my particular problem either by turning off the calendar in my Exchange account, or by setting the entire Exchange account (mail, calendar, contacts...) to be fetch only. I say "fix" with warning quotes, because it only cures the battery drain. I actually NEED my calendar and email to work and update in a timely fashion on my phone. I can't afford to miss meetings because they do not show up on my phone calendar. I NEED to have important email show up on my phone asap, not 15 or 30 minutes later.
But I'm still left with the fact that my buddy at work with the same iphone 5 is not having the same problem. I checked his phone settings last week, and it was the same as mine at the time, with push enabled for Exchange, and calendar enabled. I'm going to look at his phone again tomorrow using SysStatsLite to check that he does not have the problem and simple not know it.
In any case, I need to schedule another visit to the Apple store. Maybe there is something wrong with my particular phone. I'm willing to give them a chance to fix it.