All that you need to know about your laptop battery

Laptop by its nature mobile and is meant to be carried around freely without having to look for a source of power every time you think of using it. It is the Lithium-ion battery inside the laptop that gives its energy, to make the latter mobile. With the battery either completely discharged or dead for good, the laptop loses its charm of being independent of power from the wall socket.

Lithium-ion batteries are found to be ideal for laptops apart from powering many of our mobile devices like cell phones, MP3 players, PDAs. Because, as of this date, Lithium-ion chemistry offers greatest energy density (watt-hours per kilogram) compared to other familiar technologies like NiMH (nickel-metal hydride) (which was till recently used in powering up laptops) and Lead-acid still being used for starting our cars. Lithium-ion chemistry is so energy efficient that they have become an exclusive source of power for green cars envisaged in the near future and as a secondary source of power for current generation of hybrid cars.

Lithium polymer batteries are the recent development and have evolved from Lithium-ion batteries. Lithium polymer batteries are presently used in Mac Laptops and some of the newer Netbooks, PDAs and cell phones. The advantage of Lithium polymer batteries over Lithium-ion batteries is that they are relatively rugged and also carry higher energy density. Meaning they can last longer between charges or deliver more power at a given time.

However if you are interested in a mature technology and the mainstay in the current laptop market, it is the Lithium-ion technology. Lithium-ion batteries, no matter how good they are, are expensive and they have a definite life of 2 to 3 years from the date of manufacture. They also can bear only a definite number of charge and discharge cycles before they deteriorate.

So it is in our interest to make the optimum use of a fully charged healthy battery while in use (between charges), prolong the life of the battery as much as we can before they become dead.
Heat Exposure
Sometime we tend to use the laptop while resting on our bed. We tend place the laptop on a pillow or blanket while using it. This blocks the ventilation windows at the bottom or on the side and thereby building up heat. So the cooling fan has to run longer, to take away the heat, which in turn drains the battery and the battery needs to be recharged sooner.

Also constant exposure to heat, reduces the overall life of the battery itself needing replacement. Avoiding notebook exposure to heat is highly recommended.

At the time of selection of laptops give due consideration for the following:

• If your laptop is likely to run more on batteries than on mains (say when you are in a coffee shop, a school or university, on a plane) than choose a laptop driven by a processor with low power consumption.
• Again if you are likely to run your laptop more on batteries than on mains, then choose a laptop with a smaller screen size. Big screen means, more power is drawn from the battery to show extra pixels on the bigger screen and hence shorter battery life.
• If your budget can allow, go for laptops with solid state drives instead of the current mechanical hard disk drives which are being slowly phased out.
• Look closely at the specifications of the laptop that states how long the battery is likely to last between charges. Choose the one with long battery life. While some manufacturers (like HP, Toshiba) are explicit about how long the battery can last before it can be recharged, some skip it altogether by simply stating the number of cells in the battery say 3 cell, 6 cell or 9 cell with capacity stated in Watt-hours(WHrs) or milliAmpere-hours(mAHrs). However we can expect a 9 cell battery to last longer than the one with 3 cell or that a battery with greater WHrs or mAHrs outlasts than the one with lesser
• Sometimes manufacturers (for instance HP) provide extra-long life batteries in place of standard battery that comes with the laptop. If your preference and nature of work calls for uninterrupted work, away from a wall socket; you may want to pre-order those batteries in place of the standard batteries.
• Look for laptops that provide some utility software or hardware that optimizes the following given some usage profile. This reduces power consumption and prolongs battery life between charges.
  1. Screen Brightness (depending on whether you are indoors or outdoors or on your background lighting)
  2. Turn off an inactive screen when not required (you are away from your desk for a short period and left the laptop on.)
  3. Turn off the hard disk drive given an inactive system (you are away from your desk for a short period and left the laptop on)
  4. Ability to turn off the optical disk drive when not required (every time Windows Explorer is opened, or a file is opened within an application, Windows checks every drive in the system a feature you can turn off temporarily if you know all your files are on the hard drive. Remember power is required to spin the optical drive to access the contents)
  5. Ability to turn off integrated wireless LAN or Bluetooth connection ( with the wireless connection on, the system constantly looks for signals thereby draining valuable power from the battery. If you have no need to connect to any network or you have access to wired connection, you can turn off such connections to save power)

However don’t be misled into thinking that the battery life between charges is as per the claims in the manufacturer’s specifications. Those claims of battery life are from the results of testing under ideal conditions.

Even the choice of an operating system and within an operating system enabling or disabling a particular feature may reduce or increase battery life between charges. For instance if you look closely at battery specifications for Acer laptops, there is this note about Aero feature of Windows Vista:
“Battery life may be reduced if Windows Vista® Aero is enabled”

Take it as a rule of thumb that the battery life under real life situations will be approximately half of that. For example if the marketing data for a laptop claims 4 hrs between charges, take it to be around two hours of continuous running before a recharge. For more details you may want to read this article titled “Hurry Up and Type“.

Once you have selected a laptop, make optimum use of the battery in the ways outlined in how to extend the life of your laptop battery.

Those of you interested in additional information on Laptop batteries, may I suggest you to visit the following pages?

• How Lithium-ion Batteries Work
• Inside a Lithium-ion Battery Pack and Cell
• Lithium-ion Battery Life and Death