My iPod has recently begun to lose charge at a rapid rate, going from 100% to 10-15% in 24 hours, where it used to be above 60% in the same time and use.

Question

As the title says, my 4th gen iTouch has recently (last few weeks) begun losing charge at a rapid rate. I charge it fully until I go to bed, wake up it's at 85%. After about 12 hours, with moderate usage (browse the web for roughly 2 hours of the time, a few IMs), and by then it is either at or below 20%. This issue has not been present long, but it's becoming increasingly frustrating. I used to use it to play Netflix overnight, leaving a movie or tv show playing, and it would use about 10% (depending on the length). It now loses 10% in sleep mode over the same time.
I have a few thoughts as to why, but no idea if they'd be correct. One is that we've recently had a lot of network issues, we had two routers going at one point, and one of them had a strong signal but never allowed access to the internet (weirdly) and the other worked normally. We have finally gotten rid of the problem router, but it was around the same time this issue began, so I was wondering if different wifi signals could require more work for the iPod? It sounds stupid to me, but it's one idea.
The second is that I have not synced to my computer in over 3 months. I recently built a new computer, and never got around to transferring my music files to the new computer. I know I've had numerous app updates, new downloads, deleted a few apps, and at least one software update. Do those files linger on the iPod until synced with a computer?
Before suggesting, I have turned off location services, notifications, Bluetooth, and my backlight has always been at about 20% of the slider.
I appreciate any and all help anyone can offer, thank you in advance.

Answer 1

First, try to reset the phone by holding the sleep and home button for about 10sec, until the Apple logo comes back again. You will not lose data by resetting. If the problem comes back, try to set it up as new device, explained here:
How to back up your data and set up as a new device
It might be necessary not to restore from the latest backup, in case it contains corrupt data causing the drain.
Deleting the mail account and setting it up again might also help if your account uses push service.
Sometimes switching iCloud off and on again also does the trick.