Dell advertised 11 hours of runtime on this device.  This is about 3 hours too generous when paired up against real world tests of shipped devices.  And if you bought a configuration that did not include the 512 GB SSD, then you only have a 61 WHr battery and should expect to see 3-4 hours of runtime.  Eventually, I hope to map out the Wattage of various processes/components, as battery endurance should mostly be a simple issue of eliminating Wattage that is not providing benefits to the end-user when on battery.  Obviously, this recipe will change from user to user and from use to use, but a Wattage chart along with easy-to-follow (or pre-configure) steps for selectively stopping battery consumption by unneeded services will likely prove to the most useful start point for addressing common battery complaints.  In the meantime....

Windows 8 has a built-in command-line method for reporting battery usage and estimated life.  From a Windows command prompt, enter:

powercfg /batteryreport /output %USERPROFILE%\Desktop\battery_report.html

So you might want to know how other users have tweaked their systems to get it to last a few minutes longer between power outlets....

Tweaks for Battery LifeEdit

  • First of course, create a power profile.
  • Some have suggested disabling the touchscreen, citing the loss of battery endurance in a Samsung laptop after adding a touchscreen to it.  If I can find good data to support this (even just the Wattage of the touch sensor would be enough), I'll post it here.  It is worth noting, however, that many users have been shocked at just how much they use the touchscreen.  It doesn't replace other input methods, but complements them in a useful way.
  • At least one user has discovered that switching the trackpad driver from Dell's to Synaptics' resulted in a drop in CPU usage (and, thus, in system Wattage).
  • One user suggested going into the nVidia Control Panel and changing the default behavior to rely on Intel's HD 4600 Integrated Graphics.  Then select individual programs (such as games or 3D modeling software) to default to the GT-750M upon starting.
  • One user said that after disabling NFC and Bluetooth, battery endurance was noticeably improved.  In Windows 8.1, open the Charms Settings (Win+C), go to Settings > Change PC Settings > Network > Airplane Mode.  Then switch on or off the various radios based on your usage needs.  Theoretically, on the XPS 15 you can tap the PrtScr button, whose default function is an airplane mode toggle, but understand that turns off *all* radios (WiFi included), whereas the Charms settings can be used to selectively switch radios.  Alternatively, you can also go into Windows Device Manager and disable the radios one at a time, though it is unclear whether that stops current flow to the radios or simply stops the laptop from reporting the signals; at least one user has noticed that his laptop used a lot more power as a result of using Device Manager alone to disable NFC, Bluetooth, and discrete graphics (dropping battery endurance from 7/8 hours down to 4/5 hours on a full charge). 

High Battery Consumption when in Sleep ModeEdit

  • This system features USB PowerShare, which allows USB devices that require power to continue drawing power even while the system is asleep or shut down. This allows you to charge your smartphone without leaving your system powered on, for example. However, this of course also drains your battery if your system is not connected to AC during that time. Therefore either ensure that USB devices that draw power are disconnected from the system while it is asleep and not connected to power, or disable USB PowerShare in the BIOS.
  • See this page.