I bought a first generation ipod touch from my sister because she got a better one. Of course as soon as it came into my possession, it drains to zero if you don't turn it on every few hours. So now i just plug it in after i'm done with it. It's lame.

Every device that uses a lithium battery (ipods, PSPs, phones etc) loose battery life every time you charge them. Battery life drops to 80% one year, then to 60% the next and so on.

 

So a first generation Ipod Touch is probably a few years old and as a result has very limited battery life.

but should it drain even when it's not in use, when i turn it off normally not fully?

You mean if you just lock the ipod rather than turning it completely off?

 

Yes the battery should drain, the ipod still uses power to keep apps paused, data streaming, and so on.

 

To conserve battery turn your ipod completely off when you don't expect to use it for several hours.

But should it drain to zero in a couple of hours, it never did before a system update that i had to do to keep itunes working?