Extending Laptop Battery Run Time

I had figured out how to estimate how long my laptop battery would keep the laptop running.  Now I wanted to know how much I might extend uptime by turning off or disabling things that would use power unnecessarily.  Ideally, I would distinguish the real power-burners from the more trivial options.


A search led to the expected plethora of suggestions from sources like PCWorld, PC Mag, wikiHow, and FriedBeef.  My interpretations and notes on those suggestions:

  • Always recharge.  Lithium-ion batteries stop charging when full, and PCWorld said no harm was done by keeping them fully charged.  My Lenovo ThinkPad suggested otherwise:  it offered an “optimize for battery lifespan” option (apparently also available via BatteryLifeExtender) that would actually stop the recharge at 95%.  Apparently this was adjustable.  Some people believed that stopping the recharge at something like 50% would extend the battery’s useful life (i.e., would postpone the need to buy a replacement), especially when putting it into storage.  To prolong battery life, others suggested removing the batteries when running on AC power for extended periods, not completely discharging, using the battery at least every couple of weeks, and avoiding short charges (i.e., don’t just charge for five minutes).
  • Keep the laptop and the battery cool.  Among other things, don’t block the laptop’s cooling vents.
  • Adjust screen brightness.  This and other obvious power-reduction adjustments were available via Control Panel > Power Options.
  • Don’t multitask.  If possible, keep just one task in memory at a time.
  • Disable unnecessary processes.  To do this manually, Ctrl-Alt-Del > Task Manager > Applications tab > right-click on an unwanted program > Go to process > End process.  As a faster and more powerful alternative to the Windows Task Manager, I liked keeping Process Hacker pinned to my Taskbar.  Of course, killing processes at random was likely to cause Windows to crash; it would help to have a sense of what one was doing.  Start > Run > MSCONFIG also provided options on which services to load at startup.  I was not sure whether I was supposed to choose Selective Startup in the General tab there in the System Configuration dialog.
  • Don’t use the DVD drive.  Remove unneeded DVDs so the drive doesn’t spin.  If DVDs are needed, put their contents on the hard drive.  To do this, create an ISO of the DVD’s contents, and then view the ISO.  Create an ISO using an image burning tool (e.g., ImgBurn).  View the ISO by mounting it as a virtual drive (with e.g., Daemon Tools or Virtual CloneDrive).
  • There was advice to create a power-saving hardware profile and use it to turn off unused ports and components.  Unfortunately, it appeared that this was old advice:  hardware profiles were evidently not available in Windows 7.  Instead, unnecessary devices would have to be disabled manually.  Unused USB and MicroSD devices could be unplugged.  Other devices could be disabled in Control Panel > Device Manager > go into the subtree of the item in question > right-click > Disable.  Devices to disable could include WiFi, Bluetooth, data modems, VGA, Ethernet, PCMCIA, and keyboard backlighting.
  • Keep the hard drive defragmented.  I set SmartDefrag to fully optimize, with the option disabling defragmenting when running on battery power.
  • Consider using a solid state drive (SSD).
  • Use hibernation rather than standby.
  • Run simple tasks that require less processing power (e.g., a plain text editor rather than Microsoft Word).  When using more demanding programs, turn off or reduce extra running features (e.g., reduce the frequency of Autosaving in Word, but possibly change it back when power runs low and the machine begins sending imminent shutdown messages).
  • Lower graphics use by changing screen resolution and using more basic drivers.
  • Clean the battery contacts.
  • Go to Start > Run > taskschd.msc > Task Scheduler Library.  Right-click on scheduled tasks and choose Export (for those now being deleted, but that might need to be resumed later), Delete, or Disable, as appropriate.  Or change the conditions for tasks to insure that they run only when the computer is on AC power.
  • Add RAM to prevent virtual drive paging, but possibly subtract RAM if not needed, since apparently it takes energy to keep data in RAM.  Alternately, consider Start > Run > MSCONFIG > Boot tab > Advanced Options > Maximum Memory.
  • Speed up Windows shutdown.  There were various ways to do this (see below).

Implementing the Suggestions

Many of the foregoing suggestions were self-explanatory.  The mission, at this point, was to arrive at an experimental (but hopefully stable) state where I would be using no more than was necessary, so as to maximize battery endurance for the tasks at hand.

Process Hacker helped in the shutdown of unnecessary processes, insofar as it allowed me to Ctrl-click to select multiple processes for shutdown.  I had to run Google searches to figure out what some of the running processes were.  In some cases, what I learned led me to go into certain programs and change their settings so that they would not load automatically, because I did not really need them and did not want to have to terminate them every time I was trying to extend battery service.  I didn’t go crazy with this; I could have done more work to research some of those other processes, maybe saving a little more juice.  Mostly I terminated processes that didn’t seem immediately necessary.  I used MSCONFIG to persistently disable some services.  That is, I rebooted to verify that unchecking boxes in Start > Run > MSCONFIG > Services and Startup tabs would reduce the number of processes that I would have to close manually in Process Hacker.  It seemed that these changes may have made my system’s startup a bit quicker.

In Control Panel, I did disable a few devices in Device Manager.  I also tried the Maximum Battery Life power plan.  In lowering resolution, I encountered a warning:  “If your resolution is below 1024 x 768, some items may not fit on the screen.”  So I chose 1280 x 768 with a 50Hz refresh rate.  This setting gave me a message, indicating that it was not optimal:  it did not make full use of the screen’s width.  The results were OK, but I decided the laptop’s screen was small enough already, without this additional imposition, so I went back to the original 1366 x 768 resolution.  When I was done, I opened a PDF, a Microsoft Word doc, and an Excel spreadsheet.  The PDF didn’t work.  I went back into MSCONFIG and saw that I had disabled Acrobat.  Once I fixed that, all ran OK.  So it seemed that perhaps I had not terribly destabilized the system by terminating those particular processes.

To speed up Windows shutdown, suggestions centered around registry edits to shorten the amount of time Windows would wait before killing any processes that had not yet been closed.  But I didn’t want to have to research or rediscover the locations and correct values for those registry edits if I changed my mind later — if, for instance, it turned out that one program, or one large Word document, was requiring extra shutdown time.  I preferred the approach of using a shortcut that would let me tinker more directly with the shutdown time.  I decided that what I wanted was a shortcut that would hibernate the system without delay.  For that, the command I wanted was this:  shutdown /h /f. To create this shortcut, I went to an empty space on the Desktop > right-click > New > Shortcut > enter the command in the space where they ask for the location.

I did not do a before-and-after test, to see what difference these various tweaks made in my battery’s endurance.  For reasons discussed in another post, it probably would have been difficult (and very time-consuming) to reach a strong conclusion as to how much difference any of the foregoing measures might make.  Some of the best advice seemed to be obvious — for instance, minimizing the use of motors (e.g., hard drive, DVD drive) and other big devices (e.g., display).  But in practice, it did not prove easy to arrive at solid numbers indicating how much of a difference a given tweak might make.

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