Laptop computer design is a compromise between the power that users want and the battery life they expect. Unfortunately, portability and performance often work against each other. An extended-life, large capacity battery keeps you working longer but adds bulk and weight to your laptop. Manufacturers typically offer several options. For example, Sony's VAIO series is known for excellent battery life using conventional high-capacity or sheet batteries.
Laptop Battery Basics
Laptop batteries typically use lithium-ion technology, which provides excellent power output at a relatively low weight. They're also immune to the "memory effect" that sapped life from older nickel-cadmium batteries. They're usually made by assembling a number of small cells into a battery pack, which is why the terms "6-cell" and "9-cell" describe them. Their output is measured in milliamp-hours, a rough measure of their power capacity. For example, at 7,500 milliamp-hours, Sony's VGP-BPL21 high-capacity battery lasts 50 percent longer than the standard battery included with most VAIO laptops.
Lithium-ion batteries are manufactured in many shapes and sizes. Most laptop batteries are either wide and flat or thick and narrow. Sony's standard batteries are the thick and narrow oblong style, which provides a better power-to-weight ratio. Most Sony VAIO models use one of two similar high-capacity batteries, the VGP-BPL21 or the VGP-BPL13. Older models such as the CS and FW series VAIOs used the 7,200 milliamp-hour VGP-BPL13, while most newer models accept the higher-capacity BPL21. The BPL13 is no longer available from Sony, but it can still be found through third parties.
For users who need the ultimate in battery life, Sony offers the option of combining a regular high-capacity battery with a sheet-style battery such as the VGP-BPSC24, rated at 4,400 milliamp-hours. Together with the VGP-BPL21, the sheet battery provides a joint rating of 11,900 milliamp-hours. That's more than twice the power of the standard battery. For some users, the combination can provide enough power for 10 or more hours of normal use. Sheet batteries are designed to fit onto the bottom of specific laptop models, mimicking their size and shape. They make the laptop thicker and heavier but provide the ultimate in battery life.
Helping Your Cause
If maximum battery life is your goal for portable use, there are a few things you can do to help your Sony do its best. Remove discs from your optical drive when it's not in use and detach any flash drives you aren't actively using. Dim your screen and shut off your wireless connection when it's not needed. Use the computer's power-management utilities to reduce your usage by spinning down the hard drive between uses. Some VAIO models have a utility called the Battery Control Function, which you can find in VAIO Central. It prolongs your battery's lifespan by limiting your charge to 80 percent of full capacity. For maximum life per charge, turn it off.
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