From Vita Dev Wiki
Power Settings 
Depending on the state of some applications, such as when a slideshow or a video is playing, the system may not automatically go into the standby mode.
Wi-Fi in Power Save Mode
In some environments, the Wi-Fi connection with the access point might become unstable. In this case, disabling this function might improve the connection.
USB Power Supply
If you select this checkbox to remove the checkmark, you cannot supply power to your system when it is connected to a USB device.
Battery Charging & Duration 
- Charging using the AC adaptor willl take approximately 2 hours, 40 minutes (for both models).
- Battery Duration
Add USB connector to PCH-1x00
- http://imaginglabo.web.fc2.com/PSvita-USB.htmb (in Japanese)
- http://www.instructables.com/id/PS-Vita-1000-to-microUSB-adapter/ (in English)
Power Management IC