The iPhone gets great battery life and the iPhone 6 Plus gets really great battery life. Apple has done a lot to make everything from their chipsets to their software management extremely power efficient. Yet every feature you use, you ultimately pay for with battery life. Most times it's not a problem. If you start running low on power, you can simply plug into USB or an adapter and recharge really quickly. If we're going to be away from energy for a long period of time, however, there are a few tricks you can use to extend your battery life just a little bit longer. They'll cost you some fun and convenience, but they'll get you as far as you can possibly go.
1. Lower light
The iPhone is LCD, not OLED, so it doesn't matter much what color is being displayed, it matters if the LED backlight is on, how intensely, and for how long. To keep energy output to a minimum, go to Settings > Display & Brightness, turn Auto-Brightness off, and drag Brightness as low as you can tolerate.
Push Notifications not only light up the Lock screen, they light up the Wi-Fi or cellular radios as well. For anything that doesn't urgently require your attention, go to Settings > Notification Center > and turn Show on Lock Screen, or even Allow Notifications, to off. (I only allow Phone, Messages, and VIP Mail).
3. Boot the background
Apple does a lot to coalesce background updates so the radios don't light up any more than they have to. But if you don't need an app updating in the background, got to Settings > General > Background App Refresh and make sure it doesn't. You'll have to wait for messages or media to refresh when you open the app, but if you don't open it often, the power savings can be worth it.
Bonus: Facebook is historically a good candidate for background refresh removal.
4. Lockout location
GPS takes a lot of power. Apple uses a bunch of tricks to keep location access to an absolute minimum, but like notifications and background, if you don't need an app to know where you are, go to Settings > Privacy > Location Services and select Never.
5. Toss tasks
Apps that provice VoIP and turn-by-turn navigation can be much harder on multitasking cycles and GPS. If you're not using them, you can double click the Home button and close the app completely by tossing its card away. That'll shut down VoIP and navigation and start saving power on the spot.
Bonus: Skype is historically a good candidate for the kill switch.
6. Minimize the Motion
Animating transitions and blurring backgrounds has become more efficient, and is certainly visually fun. If you don't want or need all the effects, however, you can turn them off and save a tiny amount of processing. Go to Settings > General > Accessibility > Reduce Motion, and turn it on.
Bonus: take the built-in Clock app, and it's GPU-activating second hand, and hide it in a folder.
7. Nuclear options
If your iPhone is hot or your battery is almost drained and you absolutely need to get more time, you have a couple of options:
Kill any apps you think might have gone rogue. Even good apps can experience bad processes.
Turn off any radio that are having problems connecting. A lower signal means a higher power output.
Reboot. It's a terrible cliche but it's a terrible cliche for a reason.
Go into Airplane mode. Save your power for when you need it.
8. Your best battery savers?
I typically only use these tricks when I'm traveling. In other words, when there's no power, poor signal, or both. Otherwise I prefer to use my iPhone as much as I can and charge it as much as I need to. I do keep notifications and location to a minimum, because I consider my attention and position to be valuable, but otherwise I like using my devices.
If you have some great battery saving tips, however, I'd love to hear them. I could always use a few extra cycles at airports, conferences and more!