As soon as the driver presses on the accelerator, the gas engine will fire up and provide the driver with normal power. (automobilemag.com)
Both of them have features like normal power saver mode and extreme power saver mode, which will also help you get some added usage out of the devices. (phoneradar.com)
In my tests, I consistently got between 5 and 6 hours of operation in working sessions, using normal power management settings and occasionally stepping away from the device. (zdnet.com)