1. NickelCadmium(NiCd) is the most prevalent and rugged type of rechargeable battery on the market. NiCd batteries perform better in extreme temperatures and can endure approximately 750 charge and discharge cycles. However, they are prone to "memory effect" (discussed later) when they are not completely discharged each cycle.
2. NickelMetalHydride(NiMH) is a step up from NiCd batteries. It offers up to 40 percent additional capacity compared to a NiCd battery of equal size. NiMH batteries are not as subject to memory effect degradation. These batteries generally have a life expectancy of approximately 400 charge/discharge cycles.
3. LithiumIon(LiIon) is the newest technology in portable power. LiIon will deliver roughly twice the run time of a comparable NiMH battery. LiIon batteries are more expensive, however, and are available for a very limited number of devices. They must also be charged by a charger designed specifically for LiIon batteries. LiIon technology also has a life span of about 400 charge/discharge cycles and is completely immune to memory effect.

What is memory effect?
NiCd batteries, and to a negligible extent, NiMH batteries, suffer from what is called "memory effect." Memory effect occurs when a battery is only partially discharged before being recharged. The battery "forgets" that it has the capacity to further discharge all the way down. For example, if on a regular basis, you fully charge your battery and then use only 50 percent of its capacity before the next recharge, eventually the battery will become unaware of its extra 50 percent capacity, which has remained unused. The battery will remain functional, but only at 50 percent of its original capacity.

The way to avoid memory effect is to fully charge and then fully discharge the battery at least once every two to three weeks. This can be done by letting your laptop or cell phone run on the battery until it ceases to function. Avoiding memory effect, however, is only one step toward maximizing the life of your battery.

Maximizing means maintenance
Once you have determined the type of battery that you are using, or will use, you must provide the necessary maintenance for the battery in order to maximize its life and usefulness. This begins when you take the battery out of the box and before its initial use.

Initializing: New batteries come in a discharged condition and must be fully charged before use. NiCd and NiMH batteries should be charged for approximately 16 hours initially, and LiIon batteries should be charged for about five to six hours. For NiCd and NiMH batteries, you should run your battery through at least two to four full charge/discharge cycles before putting it into ordinary service. This will help obtain maximum capacity of the battery.

When charging the battery for the first time, the device may indicate that charging is complete after just 10 or 15 minutes. This is normal with rechargeable batteries. New batteries are hard for the device to charge because they have never been fully charged and are not “broken in.”Sometimes the device's charger will stop charging a new battery before it is fully charged. If this happens, remove the battery from the device and then reinsert it. The charge cycle should begin again. This may happen several times during the first battery charge. Don't worry. It's perfectly normal. Batteries that have been in storage or out of use for long periods of time should be re-initialized before being put back into service.

Conditioning: NiCd batteries must be fully discharged and then fully charged every one to three weeks, depending on frequency of use. Failure to do so will result in "memory effect" and will significantly shorten the battery's life. To discharge, simply run the device under the battery's power until it shuts down or until you get a low battery warning. Then recharge the battery as instructed in the user's manual. Because the NiMH battery has negligible memory effect and the LiIon battery has no memory effect, they do not require conditioning.

Exercising: The workload on a battery directly affects its run time. In order to maximize battery life, users can apply the following tips to increase the usage time and life of their batteries.

Laptop users
How can laptop users conserve battery power? Here are some tips:

• Optimize the power management features provided on your system. Managing the power used by the hard drive will save significant amounts of power and will extend your usage time.
• Decrease screen brightness. On color systems, you can save quite a bit of power by changing to black-and-white (monochrome) mode.
• Turn off the modem, if possible, and remove any Personal Computer Memory Card International Association (PCMCIA) cards not in use.
• Don't leave the power cell in the system with the AC adapter plugged in unless you're charging it.

 A few more pointers
Be sure to clean dirty battery contacts with a cotton swab and alcohol. This helps maintain a good connection between the battery and the portable device. Also, if you don't plan on using the battery for a month or more, store it in a clean, dry, cool place away from heat and metal objects. NiCd, NiMH, and LiIon batteries will self-discharge during storage. Remember to recharge the batteries before use.

When it's time to say good-bye
Most people don't think of a battery as being consumable. After a certain number of charging cycles, your battery will no longer charge fully and will not give you its initial performance. This is due to normal wear and tear, and unfortunately, you can do nothing about it. You do have a couple of options at this point, however. You can dispose of your battery and buy a new one, or you can have the worn-out battery refurbished.

Proper maintenance is the key to a battery's longevity. Only you can control that. Whether you are someone who depends daily upon your portable devices or if you use them on an as-needed basis, implementing the aforementioned maintenance tips will give you confidence and security that your laptop or cell phone won't die when you need it most.

Other Miscellaneous Laptop Battery Tips: