For my iPod Touch I like the idea but very successful, (fixed more or less) to connect the battery to the unit, the quasi produce a unit that you can act well. I würd`s dislike, somehow with a USB cable, a battery pack on the touch to have this and then to use under these circumstances continue ?!
I can live with it, occasionally time to press the suction cups again solid - is supposed to be no connection für`s life.
For reloading my Touch 4G, it is sufficient, the service life thus doubled. Enough for me. I can shop and synchronizing both quasi double-pack - for me a good solution.
Battery itself is processed very valuable. Highly recommended!