Why is my iPhone loosing its battery quickly?

Ever since I cracked my iPhone about a week ago, the battery had been going down too quickly. I used to charge it once a day at nighttime, and it would last me all day. Now I have to charge it like 2 times a day in order to keep it on! Like as I'm typing this, my phone is on 66% when I charged it about 30 minutes ago, and it was on full battery! I didn't even use my phone that much. All I did was talk on the phone, for about an hour, with the screen locked. I'm getting the screen fixed/replaced in a couple of weeks, but I don't think that's the problem. The brightness on my phone isn't all the way up, it's actually less than halfway up. I also only use the Internet when it's connected to Wi-Fi. What is happening to my phone? What do I do to fix it? How do I make the battery last longer? My phone isn't jail broken either btw. It's just a normal iPhone 4s.

Maybe you're running a lot of apps in the background? Also if siri is on it wastes your battery quicker. Then again maybe after you iPhone was damaged it just became defective it's hard to say. Try turning off siri and making sure no apps are running in the background and see if that works

I you have 3G or 4G it lowers your battery faster even if your not using it. Also make sure your double clicking the home button and clearing out all those shortcuts everyone once in a while as well as restarting your phone and turning it off at night. The more data you use the faster it runs Dow so also delete any unused apps or songs.

You should change the battery

Sorry in advance for all the writing…

as another person said, maybe you're running too many applications in the background. Make sure every so often that you double tap the home button and click and hold one of the applications until it wiggles, click the minus button until all of them are gone. No this will not remove them from your device, it just closes the applications fully so it isn't using your battery.

noticing you said it's an iPhone 4S, would lead me to believe its at least a year old, and given you're a normal iPhone user, an iPhones battery will hold greater than 80% of the entire battery's capacity up until the 400th charge cycle, which means after that 400 charge mark, your iPhone will not hold as much of a charge as it used to. (statistically it only holds 80% of the entire battery size at 400th charge cycle).so you may need a new battery. Check into a local place, that has good ratings that is able to change your battery

These instructions will ensure that you will get the most battery life out of the iPhone's charge:

- Double Tap the home button and long press on the apps that appear until they start to wiggle, then press the red X that appears to close those apps

Turn off Auto Brightness
- Go to Settings
- Go to Brightness
- Turn off

Reduce Screen Brightness
- Go to Settings
- Go to Brightness
- Drag down to where you can see it comfortably (about ¼ of the way is a great starting point; your eyes will adjust to it as well)

Turn off BluTooth
- Go to Settings
- Go to General
- Go to Blutooth
- Turn off

Turn off Wi-Fi (When not near a Wi-Fi Area)
- Go to Settings
- Go to Wi-Fi
- Turn off

Turn off Location Services
-Go to Settings
- Go to General
- Go to Location Services
- Turn off

Turn off Push Email
- Go to Settings
- Go to Contacts, Calendar & Email
- Go to Fetch New Data
- Turn Push Off

Fetch Less Often
- Go to Settings
- Go to Contacts, Calendar & Email
Go to Fetch New Data
- Go to either Hourly or Manually