iPhone has one of the best battery lives (at least comparing the same sized equivalents and not including phablets and phablet like phones) when it comes to most of the smart phones out there and the reason is mainly because of excellent hardware to software communication and optimization. However like any consumer product, a lot of variables get introduced once the product reaches the customers who each use the device differently and results generally vary a lot.
As a mid range user (I do most of my gaming on the iPad Mini), my iPhone has no issues going for an entire day with some charge left by the night. However there are lot of ways iPhone's battery life can be modulated and here are some of the most effective tips to stop iPhone from draining its battery too quickly for most of the users.
1. Ask to Join Networks
Settings - Wi-Fi
This is by far the most irritating option that has no reason to be turned on by default by Apple. When on, it keeps looking out for Wifi networks that the iPhone can join. And any sort of communication in and out of your phone drains its battery. Now imagine travelling and your iPhone constantly searching for Wifi networks, it can easily drain your charge really fast. Most of us use a few Wifi networks, like the home, office, Starbucks, etc. And once you join any one of this network by entering a password, iPhone automatically remembers this network and every time you are within the network's range, it automatically connects even if this option is switched off. Also when you are in a unfamiliar place and want to see if there are public Wifi networks to connect to, then its easy to toggle this switch on and search for new networks. This switch should remain off for majority of the time and this will greatly improve your battery life.
Setting - Brightness & Wallpaper
Retina display and 4' screens might be good for usability and result in much better user experience with the iPhone, but these things take a toll on the battery life. Make sure the iPhone's brightness setting is ideal for your usage. I like to crank it up whenever I need it, like while using it in a bright area. But turning Auto-Brightness on accomplishes the same task and does it effectively most of the times. Too bright screens over long times can easily reduce the iPhone's battery to zero very soon. After all staring at too bright a screen for long times cannot be good for your eyes also, can it?
3. Location Services
Settings - Privacy - Location Services
Location services are those which have to know your current location (geo coordinates) for various reasons (like Maps for example), but again as mentioned previously this means communication between your iPhone and outer world and this consumes battery power. The Location Services pane gives you the control to turn on and off the feature for individual services. But when you have a boatload of applications like I do, then managing these becomes a pain. So what I do is turn Location services off now and again and every time an app wants to use your location it will give you an option to turn on the Location Services. Either way keep monitoring this and battery life should improve.
4. Fetch New Data in Mail
Settings - Mails, Contacts, Calendar - Fetch New Data
Another common reason for uncharacteristic battery drain is the Mail app that tries to look for new mail too often. Any mail service either pushes (Yahoo) new mails directly from the server to your iPhone or fetches (Gmail) new mails from the server periodically. In case of Fetch, iPhone can let you control the frequency at which iPhone looks for new mails, either every 15 minutes, 30 minutes, 1 hour or even manually (i.e. the iPhone looks for new mails only when the user manually asks it to do so). Anyway depending on your comfort level this option can be modified to yield better battery life. The Advanced option in this allows manipulation of either Push (when available) or Fetch or Manual option for individual Mail accounts as well.
The aforementioned pointers will show an immediate effect on battery life for the majority of the iPhone users. However there are many other factors that affect your iPhone's battery life , like
- Spotty reception means worse battery life as the iPhone is constantly looking for better signal to hold on to. So turn Airplane Mode on (Settings) when you know there is no cell reception in the area.
- Too many Push notifications (Settings - Notifications) can affect battery life, so disable least used apps' push notifications and turn it on when needed.
- Making sure that the iPhone is locked when its idle by either manually locking it every time or enabling the Auto-Lock feature (Settings - General - Auto-Lock).
- Use WiFi (when it is available) over LTE (Settings - General - Cellular). I don't like this option as AT&T LTE is much faster than WiFi and I have a grandfathered unlimited data plan.
There are still many more factors that affect iPhone's battery life and visit Apple's support page for iPhone battery life questions and solutions. Note this point mainly, "For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down)." I have heard this one from many of my electrochemistry friends not just for iPhone batteries, but for all your electronics that use lithium ion batteries.