Why I cannot get the battery life as advertised?

February 15, 2013 By | Add a Comment

If you have shopped for your laptop by looking at the advertised battery life, you may have disappointed how short your laptop’s battery life was. This posting explains why there is so much difference between advertised battery life and your actual experience.

How PC vendors measure battery life of their products?

Most of the PC vendors in the US market use MobileMark 2007 Office Productivity benchmark that is consist of the following applications.

  • Microsoft Office 2003 (Project, Excel, Outlook, PowewrPoint, and Word)
  • WinZip 10.0
  • Adobe Photoshop CS2
  • Adobe Illustrator CS2
  • Adobe Flash 8

Benchmark runs these applications automatically and emulates typical office use to measures how long the laptops can run with one battery charge.

Note: MobileMark 2012 was released a while ago, but it does not seem to be widely adopted at this point (February 2013) yet.

What makes the differences between advertised battery life and your experience?

There are many reasons, but some of the major reasons are:

  • Battery capacity

    Sometimes PC vendor runs the benchmark with large capacity battery, which is not the default configuration. Please read the fine print or visit MobileMark 2007 Full Disclosure Report database to find out which battery was used for the benchmark. If you have 6-cell battery and the published battery life was measured with 9-cell battery, you can expect only 2/3 (= 6 cell / 9 cell) of the published battery life.

  • Workload differences

    If you are running heavy games, your battery life will naturally be much shorter than MobileMark 2007 results.

    Even if you are running office productivity workload that is similar to MobileMark 2007, your battery life may be shorter than MobileMark 2007 result because newer version of applications (e.g. Office 2010) may use more resources than the older version used in MobileMark 2007.

    If your main workload is web browsing, your battery life widely varies depending on what website you visit and what kind of activity you make at each site, but considering more dynamic nature of modern web designs, web browsing can be much more demanding workload than MobileMark 2007 Productivity benchmark.

  • WiFi setting

    MobileMark 2007 is usually run with WiFi disabled.

  • Display brightness

    MobileMark 2007 is required to run with display brightness at 60 NITs, which may be a little bit dimmer than many people prefer.

What does the advertised battery life mean to you?

So, now you know that you cannot get the same battery life as advertised. Does this mean that the MobileMark scores are useless? It does not needed to be. It is still useful data when you use it right. Here are some examples where the score is useful.

  1. Compare battery life performance between laptops

    As MobileMark 2007 defines test procedure well, you can expect reasonably fair comparison between laptop models even they are from different vendors.

    For different kind of workloads, absolute battery life will vary, but the laptop with better MobileMark 2007 score usually do better with other workloads, too.

  2. To determine how well your laptop is power managed

    You can compare your laptop’s battery life to the advertised battery life to find out how well your laptop is power managed. You probably do not want to run Mobile Mark 2007 on your laptop (it costs $750!), but by:

    • Disable WiFi,
    • Disable screen saver,
    • Set display brightness to the lowest brightness and disable all power saving timers,
      Figure 1. Power plan setting for run-down test
    • And leave your laptop idle until the battery drains.

    Your laptop should be able to stay on for more than the advertised battery life (because of less activity than MobileMark 2007 and lower backlight brightness). Nevertheless, many laptops drain battery in (much) shorter time. If this is the case for you, your laptop is not optimally configured and/or unwanted programs are draining your battery in the background. This means that there are many things you can do to improve the battery life.

    Using our Battery Life Maximizer is one way to find out what is wasting your battery power. It finds both software and hardware problems in your laptop and helps you to get most out of your laptop.

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