David Pogue from the New York Times recently got some tips on improving iPhone battery life from an Apple Store Genius. We've discussed how to get the most out of your iPhone's battery on TUAW before, but it's worth revisiting since both the iPhone itself and the software it runs have changed so much since the last time we discussed it.
Three out of Pogue's four suggestions for improving battery life come straight from Apple's official battery life tips. First, he suggests turning off push email and setting email to fetch manually. Depending on how many email accounts you have, this could dramatically improve your battery life, but it also means you won't receive new messages until or unless you open the Mail app.
Pogue's second suggestion was to turn off Location Services for apps that don't necessarily need to have an active GPS connection. This tip makes sense if you're making heavy use of a camera app or a Twitter client with GPS tagging, but since Location Services generally doesn't run in these apps when they're running in the background, it's only going to make a positive impact on your battery life if you're spending a lot of time using these apps.
The third tip was to turn off notifications for most apps, which Pogue says reduces the number of apps needing to monitor your iPhone's status. I turned off notifications for most of my apps long ago, but not just out of concern for battery life; I was getting tired of various alerts going off on my iPhone every five minutes or so, especially since there's no global setting to turn off all notifications during the hours I'm normally asleep.
The final tip isn't one you'll find on Apple's official tips page, and Pogue himself admits that it seems odd. The Apple Store Genius he spoke to recommended quitting backgrounded apps by bringing up the multitasking tray with a double tap of the Home button and holding down on app icons until they start wiggling and minus symbols appear on them. According to Pogue, the Genius quit around 40 backgrounded apps on his friend's iPhone this way. As Pogue acknowledges, this tip seems a bit weird considering Apple's official stance on multitasking in iOS 4 is that apps running in the background aren't actually running, and therefore shouldn't be drawing battery life at all. That having been said, I tried this out myself earlier this week when I noticed my iPhone 4's battery was barely lasting a full day even when I wasn't using it at all, and I saw an immediate improvement. Naturally, this tip is specific to devices that are capable of multitasking and that are running iOS 4, which means iPhone 3G owners needn't worry about it.
In addition to Pogue's tips, two things I've noticed have a fairly big impact on the iPhone's battery life are the screen brightness and Bluetooth. In general, it's a good idea to keep the screen brightness as low as you can while still being able to make out what's on-screen. As for Bluetooth, unless you're actively using it with a headset or Personal Hotspot, you should probably turn it off. Even if you're not connected to a Bluetooth device, the iPhone will still periodically scan for such devices if Bluetooth is activated, and that'll run down your battery pretty quickly.
Got any other battery-saving tips that we didn't cover here? Let us know in the comments.