Q: How do I adjust how long my Surface Pro 3 stays in Connected Standby mode before hibernating?
A: The Surface Pro 3 supports Connected Standby, which means initially when in sleep mode the machine operates in a very low power mode to keep modern applications running and up-to-date; however, this setting does use additional power compared with a hibernate (which uses no power). To change how quickly the transition from Connected Standby to hibernate occurs, you can set two values: one for when plugged in, the AC value, and one for when on battery, the DC value.
powercfg /change hibernate-timeout-dc <minutes>
powercfg /change hibernate-timeout-ac <minutes>