Monday, June 20, 2011

XPS 15z: Amazing battery life of 6-7 hrs for general use

I had been monitoring the Dell XPS 15z battery performance for last several days and I can now safely say that I get around 6-7 hours of battery for a normal use for me. By normal everyday use, I mean internet browsing with WiFi always on, chatting with friends, occasionally listening to music using an earbud headset, reading some e-books, writing some reports using Microsoft word, Windows explorer file copy/paste/move operations, browsing files/pictures on the hard disc, installing software here and then, downloading some files, remote connection to Linux work stations/supercomputers over SSH (secure shell) etc. Now if you just want to read an ebook or type in word and only occasional WiFi (disable/enable WiFi using Fn+F2 short key), you may get more than 8 hrs.

Here are some battery monitor logs collected by BatteryMon software from PassMark (

In the beginning: 7 hrs of battery estimate

After 30 mins: Cloud streaming Google Music songs ( with Firefox 4 browser for 10 mins drop down the overall battery life estimate to about 6 hrs. i.e, if you wanna stream music all the time, and browse normally you can use the laptop for 6 hrs max.

Returning to normal browsing and now the battery life estimate is back to more than 7hrs (7.5 hours of total estimated time).

 I used windows power saver option with lowest screen brightness(which is still good in a not-so-bright room). Since I do not use bluetooth,  I disabled all the bluetooth associated services.

Control Panel>All Control Panel Items>Administrative Tools>System services
There are four services with bluetooth name and right click on it. Go to properties and stop the service if t is running and change the startup type to 'Disabled'.Click ok. 

Also I disabled a few useless stuffs like Adobe updater, Adobe active file monitor, Dell Datasafe online bacup etc. (WARNING: Be careful in disabling stuffs like that. It may adversely affect your system performance. For example, if you disable Quickset using msconfig, it might result in a defunct DVD eject button.) One thing I must say is that I do not have any clear quantitative estimate of how much battery these services take up. May be some are harmless to battery life even if it is running in the background. Try yourself and find it out.

Now what will drain your battery for sure: 
1) The number one common thing could be playing flash videos while browsing; any news site  like CNN/MSNBC or youtube or all those annoying ads from 100s of sites. My recommendation is use Firefox browser with AdBlock and Flashblock if you happen to visit ad added sites.

2) Dell XPS 15z HD screen is exceptionally bright. I suspect full brightness use when not plugged in would negatively affect not only the battery meter reading but also the overall battery life. So make sure you decrease it. Also may be change default display colors to generic in Mobility center (Windows key + X)

There are many obvious stuffs which will drain your battery like playing video/DVD/running CPU intensive programs (games, video editing etc) etc. But I can assure you, this battery is simply awesome.

UPDATE: If you want to save a little more battery life, you may want to kill two cypress processes (CyCpIo.exe and CyHidWin.exe) through task manager (Ctrl+ Shift + Escape). However, you would lose minor touchpad functionality.

UPDATE: (2nd August 2011) I just found out a side-effect of disabling all the bluetooth services. If you go to Devices and Printers and you don't see any content but windows OS keeps on searching for ever, you have this problem. To fix it go to Control Panel>All Control Panel Items>Administrative Tools>System services and right click on Bluetooth Support Service > Properties  and make Start up type Manual. Then start the service. If you have that Devices and Printers windows open, your all devices will be shown instantly. wow!
Some interesting Web pages

Browser Face-Off: Battery Life Explored

Top Tips to Extend Your Laptop Battery Life,2817,2324229,00.asp

Laptops with the best battery life


  1. You've just convinced me to get myself the same i7 15z model you bought yourself. I've been on the lookout for a decent laptop with a 1080p screen that's thin, and with a long battery life.

    Many thanks for posting about it and the useful tips about disabling the bluetooth etc.

  2. @Glenn Thomas:
    You're welcome. I'm glad that my blog posts were useful for you and I'm sure you'll enjoy the XPS 15z experience as much as I do.

  3. i just want to ask if there is any option so i can stop using the battery at home and keep on charger to save battery

    1. Did you mean stop battery charging while plugged in at home? Yes, you can do that and it'll probably increase life span of the battery.

      Right click on battery/power icon in system tray, click Dell battery meter and check the box that says turn off battery charging. It'll be good till you restart your laptop.