IPhone 5 :: Finding Out Why Battery Is Draining

I have an iPhone 5 that I accidentally left in my pocket when I went swimming a couple months ago. Yeah. 20 minutes under water in my pocket rendered it useless. I tried the rice trick, but it did nothing, so I opened it up and let it sit in front of a fan for a few hours. This may have solved most of the problem, but I accidentally dropped it while it was open, and the screen ribbon tore.Â

On a on a whim I tried plugging it in to charge and I got the vibrate indicating that it was charging. After an hour, I plugged it into a laptop, and iTunes came up, but I couldn't connect, since the phone was asking if I trusted the laptop, and I couldn't answer, as the phone's screen was nonfunctional.So, rather than pay $700 for a new one, I opted to try replacing parts.Â

I bought a new screen and tools. Replacing the screen was easy, and lo and behold the phone worked! However, the ear speaker did not work, and the battery drained in 1/4 the normal time. So I bought a new battery and ear speaker / FaceTime camera assembly. After replacing those I noticed that the battery still drained fast, and also noticed that the forward facing camera did not work, so I bought a new camera, hoping that the fast drain was because of that. I've now replaced four parts (for a total of $100), and the phone works fine, except the battery still drains very fast. For instance, if I'm at 100% when I go to bed, and all apps are shut off, when I wake up it's at 50% or less.Â

is there an app or some sort of something that can look at the details of power usage in my phone and let me know if any parts are shorting out or require replacing? Clearly my phone is no longer under warrantee since all three water sensors (well, two, I guess, since I replaced the screen) are red, and four of the parts have been replaced (all Apple OEM, by the way).Â

Info:
iPhone 5, Windows 8