Notebook PCs were invented to allow mobility. Their original purpose was the dream of all-day computing without being connected to a nearby wall outlet.
Although portables have become exponentially more powerful, battery technology has not kept pace. There remains a constant trade-off between power drain and solid computing performance. Fortunately, operating systems have become more resilient and flexible in meeting user needs.
Here are five tips that will postpone the search for a wall outlet:
Because today’s notebooks come with multifrequency 802.11 radios, Bluetooth, cellular data cards and more, it’s no surprise how quickly a battery can run low.
The key is to power down devices when not in use. Bluetooth and cellular data cards are the worst offenders and will drain a battery with a fierce determination. Shut them off through the device manager on your notebook to ensure they are powered down until needed.
Also, if you are not accessing any online services, consider turning off Wi-Fi as well. Although not as much of a power drain as other devices, it still makes a dent. Alternatively, some Wi-Fi radios in their resident application have a power-saver mode. If available, give it a try.
Users frequently overlook the number of attached external devices their notebook is powering. How often do users leave a USB CD-ROM or an MP3 player plugged into their notebook while on the go?
Remember: These devices draw power from the notebook, and it adds up extremely quickly. Whenever possible, unplug them.
For users running Microsoft Windows 7  (or Vista), there are several built-in features that can help improve hardware efficiency.
Under Advanced Power features, select Processor Power Management, then change the On Battery Maximum Processor State to 50 percent. The CPU will work at half speed while running off the battery. Modern CPUs are more than powerful enough to accomplish most tasks while running at half speed.
In the same section, reduce the setting for the Hard Drive Timeout. The hard drive will spin down sooner, adding to the battery savings.
Certain notebook models — primarily HPs — come equipped with ambient light sensors. This automatically adjusts the screen brightness depending on the lighting at your location. This is a great feature and highly recommended to anyone who wants to automatically save battery life. But if this is not available, simply lowering your screen brightness manually can easily add an hour to your productive unplugged time. Most notebooks will have labeled keys along the top of the keyboard that allow for quick adjustments.
Standby mode allows for an almost instant return to work after a power down, but the unit continues to draw power while in this mode. Granted, it’s a very small amount of power, but if left on Standby overnight, your notebook will need a wall outlet upon the next day’s power-up.
Hibernate mode alleviates this power drain by copying all the running information to the hard drive and completely shutting down the system. There is zero battery drain, and your power-up, while not instantaneous, takes only seconds more than in Standby, still significantly faster than a cold boot — with all your programs open.