EyeTV Mobile uses the iPad 2 battery for most of its power needs.
It also has a small, internal battery as well.
If EyeTV Mobile’s internal battery does become fully drained, then connect EyeTV Mobile to a computer or USB power adapter to recharge it.
One example of a USB power adapter is what Apple provides to charge an iPod or iPhone via a power outlet. That will also work with EyeTV Mobile, as will other USB power adapters.