How long does it take for itouch 4 to charge fully from a notebook?

So many articles on diff. pages tell different things, so I want to hear it from Apple.

Is it healthy to let the battery die compeltely and then charge it fully?

If yes, what is the exact time it takes to charge it fully, and not overcharge?

Is it unhealthy to overcharge?

Thanks for you help!

soultrekker

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