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Batteries, Batteries, Batteries!

In this article, we’ll take a look at the four most common types of notebook computer batteries: Nickel Cadmium (NiCad), Nickel Metal Hydride (Ni-MH), Lithium Ion (Li-Ion), and Smart Batteries. I hope you get a charge out of it!


Nickel Cadmium (NiCad) is a popular, durable type of rechargeable battery, frequently used in notebook computers. NiCads are quick to charge, last approximately 700 charge-and-discharge cycles, and work well in extreme temperature conditions. Unfortunately, NiCad batteries suffer from "memory effect" if they are not completely discharged each cycle. In other words, if the battery is at half capacity when you attempt to recharge it, instead of being charged completely, the “memory effect” reduces the overall capacity and run time of the battery.

Nickel Metal Hydride (Ni-MH)

Nickel Metal Hydride (Ni-MH) batteries are the cadmium-free replacements for NiCad batteries. They are less affected by the "memory effect" (the inability to recharge completely unless the battery is fully discharged) than NiCad and thus require less maintenance and conditioning. However, they have problems at very high or low room temperatures. Don’t we all? Even though Ni-MH batteries use less hazardous materials, they cannot be fully recycled at this time. Another difference between NiCad and NiMH is that NiMH batteries offer higher energy density than NiCads. In other words, the capacity of a NiMH is approximately twice the capacity of its NiCad counterpart. This translates into increased run-time, with no additional bulk or weight.

Lithium Ion (Li-Ion) Batteries

Lithium Ion (Li-Ion) batteries are the new standard for portable power. Li-Ion batteries produce the same energy as Nickel Metal Hydride batteries, but weigh approximately 20- to 35 percent less. They don’t suffer from the "memory effect" (the inability to recharge completely unless the battery is fully discharged) unlike their NiMH and Ni-Cad counterparts. Lithium Ion batteries are composed of non-hazardous materials, but because lithium ignites easily, special handling is required. Unfortunately, few consumer-recycling programs have been established for Li-Ion batteries at this time, but hope springs eternal.

Smart Batteries

Smart batteries are not really a different type of battery, but they do warrant their own category. Smart batteries have internal circuit boards, with chips, which allow them to communicate with a notebook computer and monitor battery performance, output voltage and temperature. Smart batteries will generally run 15% longer than other batteries due to their increased efficiency. They also provide the computer with accurate "fuel gauge" capabilities to determine how much battery run time remains before the next recharge is required.

Computer Battery Tips

1. You cannot change battery types unless your laptop computer has been configured by the manufacturer to accept more than one type of battery. The recharging process is different for each of the three primary types of batteries: Nickel Cadmium, Nickel Metal Hydride, and Lithium Ion.

2. A battery that is not used for a long time will slowly discharge. Even with the best of care, a battery needs to be replaced after 500 to 1000 recharges.

3. It is not recommended to run a laptop without the battery while on AC power. The battery often serves as a capacitor to protect against voltage spikes from your AC outlet.

4. Because manufacturers change the shapes of their batteries every few months, you might have problems finding a new battery for your laptop after a few years. This is a concern only if you plan to use the same laptop several years from now. If in doubt, buy a spare battery now, before it's out of stock. Check out,, Planet Battery, or BatteryWeb.

5. New batteries typically arrive in a discharged condition and must be fully charged before use. It is recommended that you fully charge and discharge a new battery two to four times to allow it to reach its maximum rated capacity. It is generally recommend that you perform an overnight charge (approximately twelve hours) for this. Note: It is normal for a battery to become warm to the touch during charging and discharging.

6. When charging a battery for the first time, the device may indicate that charging is complete after just 10 or 15 minutes. This is a normal with rechargeable batteries. Sometimes a charger device 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.

7. Keep your battery healthy by fully charging and then fully discharging it at least once every two to three weeks. Exceptions to the rule are Li-Ion batteries, which do not suffer from the “memory” effect.

8. Batteries should be stored in a discharged state since they will self-discharge and may become inactive after a long storage period. Batteries should not be stored for any length of time while connected to a laptop computer.

9. High humidity and temperatures can cause any battery to deteriorate, so store batteries in a cool, dry location.

10. Do not remove and carry a battery pack in your pocket, purse, or other container where metal objects (such as car keys, paper clips, or switchblade knives) could short-circuit the battery terminals. The resulting excessive current flow can cause extremely high temperatures and may result in damage to the battery pack, cause fire or burns, or your hair to stand on end.

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