Last week, a few days after upgrading to v2.2, I noticed a huge difference in the rate in which the battery was draining on my iPhone. After it had charged all night, you could almost see the charge meter dropping with the naked eye. OK, so I’m exaggerating a bit here… but it certainly was enough of a drain for me to notice. By mid-day, the meter was at around 20% left, and giving me the warning notice. Flustered, I set out on a mission to figure it out.

What could be running all the time that would cause a drain on the juice? Well, I have my work email account configured to sync mail, contacts, and calendar via ActiveSync. This was the only culprit I could think of that would run all of the time… at least when I had the push feature enabled. I did a few days worth of testing and here’s how it went.

• Day 1: Charged the phone overnight and left push and fetch off (as I normally do to avoid being awoken by new emails). At 6am, I turned both push and fetch on. I typically set fetch at every 15 minutes, so I left it as such. 
  • Results: After 2 hours, the battery was down to 50%. This was 2 hours of very mininal use, pretty much sitting on my desk for all but maybe 10 minutes of use. No phone calls, no internet use, no texting, etc.
• Day 2: Charged the phone overnight and left push and fetch turned off. At 6am, I turned only fetch (15 minutes) on.
  • Results: After 2 hours, the battery was down to 90%. Again… no phone calls, no internet use, no texting, etc.