iPod makes gains, yet battery life loses

Apple has sold over 10 million iPods in the past four years, with new features and versions of the trendy digital music player being introduced constantly. Its short battery life, however, remains one of the most controversial aspects of the iPod, and has not seen any recent improvements.

In November 2003, a video began circulating the internet entitled "iPod's Dirty Secret" which revealed the fact that an iPod's battery only lasts about 18 months. After these 18 months, the music player must be sent back into Apple to be refurbished for a hefty cost.

Since then, the AppleCare program has introduced a battery replacement charge for much less than the $250 refurbishment highlighted by the film. However, many consumers are still wary of the $99 battery replacement fee. With a little understanding of batteries, however, you can perhaps appreciate the fact that Apple is doing its best, and you can maximize the battery life of your music player.

iPods, as well as most other digital music players, are powered by lithium-ion batteries, the same type of battery found in many laptop computers and cell phones. One of the perks of this type of battery is its power-to-weight ratio, meaning that it is advantageous in light weight electronics.

All batteries, including lithium-ion batteries, produce power in the same way. A reaction between two chemicals occurs inside the battery.

One of the chemicals gives up electrons, becoming positively charged, while the other gains electrons, becoming negatively charged. The electrons which gather at the negative side of the battery then flow out of the battery, through the wire (and whatever it is attached to), and end up back at the positive side of the battery, eventually neutralizing this charge.

While most batteries must be disposed of after this charge is used up, a rechargeable battery can be plugged in and uses this electric current to rebuild the charge difference between the poles of the battery.

The way that batteries vary from one another is in what chemicals are used in the reaction that generates electrons. The first battery ever built was made in 1800 by Alessandro Volta with zinc and silver.

Batteries common in today's electronics include zinc-carbon batteries, also known as standard carbon batteries, which vary in size from AA to D.

Other types are metal-chloride batteries that are used in electric vehicles, zinc-mercury oxide batteries that are used in hearing aids, and zinc-silver batteries, which are very light, have applications in aeronautical equipment.

Since a portion of the chemicals in a battery are lost each time it is recharged, even the lithium-ion batteries found in iPods do not have an unlimited lifetime, but are estimated to last 300 to 500 charge/discharge cycles.

There are things you can do, however, to maximize this, and these hints apply to all electronics with rechargeable batteries, not just iPods.

First of all, batteries are happiest at room temperature, so don't leave your iPod in a car in the hot sun.

Always use the hold button on your iPod, so that it won't accidentally turn on when you're not listening to it.

Although lighting up the screen seems pretty cool, the backlight feature uses up more battery than you might expect, so turn it off to maximize battery life. The same is true when using light features on your cell phone.

Switching tracks in the middle of a song takes slightly more battery power than just letting all the songs play, so don't use your forward/ backwards button a lot.

The best piece of advice to follow -- and this definitely goes for all rechargeable batteries -- is to not let your battery discharge below 40 percent.

The iPod battery meter is not particularly specific, so when it looks like about half empty, it's probably time to plug it in. In addition, although the battery will be 80 percent charged in an hour, it takes another three hours to fully charge the battery, and it is best to let this full charge happen.

If you have an aging iPod and are still worried about having to replace the battery, know that there are now third party companies, like http://www.ipodbattery.com,which will send you a new battery, and instructions on how to install it, for as low as $29.95. These instructions involve prying the lid off your iPod with a screwdriver, disconnecting a tiny cable, and ripping the old battery off from where it is glued on. However, if you are doubtful about your electronics skills, a $300 iPod may not be the best thing to practice on.

Although there are no amazing chemistry-defying new batteries on the upcoming market, research is certainly being done on how to increase battery life.

Batmax, for example, is a tiny sticker that has just entered the cell phone market. When attached to a cell phone battery, it increases the battery life and decreases recharging time. Other high-tech batteries utilize solar power but are not available commercially.

A recent Economist article observed that battery technology is not keeping up with demands on the market or with advances in other types of technology. It states that consumers face "stark choices" and calls the situation a "mobile energy crisis." So until this crisis is solved, keep your power cords handy.