Yes I have tried battery calibration, doesn't help. It just drains and drains and drains. I don't keep apps in the system tray either unless I am using them and I only have 1-2 apps that use background refresh. Brightness is at like 30%. I had the same exact problem with the 4th gen touch except the drain was so much worse on that one. It just seems like the batteries on these devices start to fail after 1.5 -2 years. The touch battery cannot be replaced due to the fact that it's heavily soldered in and paying apple $80 for a battery replacement on something that really should last longer without showing signs of deterioration is not an option for me especially since this is an outdated device.
I also do not like the fact that the battery meter jumps around, it will hit red then when you close the app you are using and press the top power button to sleep the device it comes back up to 75% or so. Of course after that it will drain again when you start using another app.
I do not have problems with batteries on other devices, just these apple ones. Other devices my batteries last years and years without signs of failing and they drain gradually, not bouncing around. Oh yeah my iPad 2 is fine as well, has great battery life.