The following factors may drain the battery faster than normal;
Ensure that you are fully charging the battery by keeping it in charge for at least 4 hours to make sure.
another option is that the battery may be infact defective.. contact manufacture for instructions on ordering a replacement!
The "black wallpaper" trick is false for many phones. It depends on the technology in your screen's display. Most phones are made with LCD or AMOLED. And the majority are LCD (IPS, S-IPS, etc). The two technologies work in different ways. In simple terms, they are opposite of each other.
In LCD, the backlight is always on, and the "pixel" is closed to cover the light, thus creating black. What that means is, it doesn't matter if your background is all black or all white, you're using the same amount of energy to light the screen regardless. In fact, some tests have shown that using all white is actually more efficient in some cases.
However, AMOLED is different. There is no constant backlight and it uses energy to only light the pixels that are active. That's why blacks are so dark on these screens. In this case, usign a black wallpaper will indeed save you some battery life.
Hope that clarifies things for a few people.
One of the main things to avoid from what I heard is to keep the phone on charge during night. Those 8 hours of sleep without unolugging it will damage the battery as it remains unused for ~5 hours on the plug.
It drains the durability pretty quickly.
You might also want to get some true black wallpapers if your phone supports that. The darker the display, the longer the lifetime. (Obvious). Along with all the tips suggested by Lachlan
plug in over night won't be a problem, if you are not using a low quality charger.
This is an old thread, but I would like to add a few things for people with recent Android handsets.
1. Turn off wifi scanning - this is a feature that will keep your wifi on 24/7 even if you do not have wifi turned on. It will scan wifi networks in the background when the phone is off (screen off, not turned off). This was probably the single most battery draining feature on my LG G3.
2. If you do not use google now, turn it off.
3. If you do not use Google Fit, turn it off. There have been reports of it draining the battery as it tries to keep track of your movements... thereby keeping the phone from going to sleep.
4. Reduce the number of Google services you sync. In your account, Google, by default, will sync just about everything it has services for. Turn off ones that you don't use like Google Newsstand, Google Play Books, etc.
5. If you don't use location much, set the location settings to battery saving instead of high precision. Google maps will use high precision, so when you launch that app, it will ask you to switch it back to high precision. If you say yes, you will have to manually turn it back to battery saving. If you don't use any location aware apps, just turn off location altogether.
6. Turn off NFC, Smartshare, media server, android beam, etc. until you actually need to use it.
7. Go into the settings of each of the apps you use and turn off anything that allows it to phone home (ie. "allow app to send usage stats to better improve..."). also if the app periodically syncs, decrease the frequency in which it does it. I have a weather widget and it has various update frequencies one of which is update when you turn the screen on. I set it to once every 6 hours, as around here, weather doesn't change that fast.
8. If your phone has a feature that monitors emergency broadcasts from the cell network, turn it off. I believe Canada doesn't have this feature implemented - similar to emergency broadcasts over RDS on your car radio.
After doing the above, I got pretty good battery life. During my day at work with light usage, I would get by with about 70-75% battery at the end of the day 8am-5pm.
Then I rooted the phone and disabled a lot of the LG installed bloatware and services using 3C Toolbox (a powerful and potentially dangerous app for the beginner as it can render your phone unbootable if you don't know what you're doing). Then I downloaded the app call Root Booster and ran it for battery saving. I was skeptical about this app at first, but it was created by a person at xda-developer. Now, for a given day with light usage, I can get by with 90% battery at the end of the day 8am-5pm. I can get 5 hours screen on time with moderate usage - lots of Google+, Chrome, Gmail, but very little video streaming or playing.
An app called BetterBatteryStats is an indispensable tool for rooted and non-rooted phones that tells you what app, service, or activity is holding WakeLocks. WakeLocks are events that prevent your phone from going to sleep. Normally, an app will periodically hold a wakelock to do something, then release it in a very short time. For example, gmail will sometimes cause this when you get mail. But sometimes, a poorly written app will cause several thousand wakelocks in a day. These are the ones you need to get rid of. Sometimes, the service will be named very weird, but a google search will tell you what it is.
Sorry for the long winded post, but it seems like non-pure Google Android phones from Samsung, LG, Asus, etc. all suffer from poor battery life simply because it's loaded with apps and services that continually keep the phone working and not sleeping when not in use.