Help with a Dell Latitude e5450

1)How can i make the usb powershare to be working when the laptop is off?

I mean, i activated the option on the BIOS, but it doesnt works, at least not as how i expected. Laptop needs to be sleeping in order to usb powercharge to work. Is there a way to activate it so that it works when it is off?

2) How much does baterry last? And how can i calibrate the laptop's battery?

I have read in different places that this laptop can achieve at normal use up to 8-10 hours. In powersave mode, i only get 7 and a half. Do i need to replace it or what can you suggest me to do?