Nintendo has confirmed that the Nintendo Switch will not be compatible with Nintendo Wii U or Nintendo 3DS games. According to the company the Switch is not the successor of the Wii U so the games will not be compatible.
Nintendo does not yet want to comment on how long the device's battery will last when it is not inside the console dock. That information will most likely be released at a later date. When gamers purchase the Nintendo Switch it will come with the left and right Joy-Con controllers that were also visible in the reveal trailer.
Nintendo Switch is expected to launch in March of 2017.