Laptop batteries provide power to laptops and their internal components, including disk drives, speakers, and fans. They may be used as a primary power sources or as backups when AC power is not available. Most laptop batteries are rechargeable and designed for specific laptop models. Batteries last from two to five hours on desktop replacement laptops, but because newer models are optimized for power efficiency, some batteries can last up to 16 hours.
Types of Laptop Batteries
Kinds of Laptop Batteries include the following:
Nickel cadmium (NiCd) batteries
NiCd batteries are relatively expensive, but have a high power output.
They are usually heavier and less efficient than other battery types.
They are prone to memory effect, a loss of maximum power caused by recharging before the battery reaches a full discharge.
Their cadmium content can explode and cause substantial pollution when incinerated.
Nickel metal hydride (NiMH) batteries
NiMH batteries are cheaper than NiCD and have a higher power output.
They are also safer and more efficient, but are still prone to memory effect.
They are suitable for high-drain applications, such as multimedia displays, video capture, and playing music on loud speakers.
They are less popular than lithium-ion batteries, but are still found in older laptops.
Lithium-ion (Li-Ion) batteries
Li-Ion batteries have a longer battery life than NiCd and NiMH batteries.
They are very light and compact, making them ideal for high-end, ultra-portable laptops.
They have very low self-discharge and will not discharge the laptop when on standby.
They tend to lose maximum capacity over time, regardless of discharge cycles. A typical battery loses about 20% of its capacity every year.
Choosing Laptop Batteries (Buying tips)
Power meter: Choose a laptop battery with a power meter that allows you to monitor battery life. Look for one with an on-screen indicator and low-power alerts. Make sure the readings are accurate – some batteries are off by as much as 30 minutes.
Weight: Choose a lightweight laptop battery if you do a lot of mobile computing. This is usually indicated by energy density, which simply means the power output in relation to the battery size and weight. Lithium-ion batteries are usually the lightest and slimmest.
Recharge: Choose a laptop battery that reaches full recharge in minimum time. NiCd and NiMH batteries automatically recharge when connected to fixed, while Li-ion batteries recharge only at low voltages. Look for one with an auto-shutoff feature that turns off the charger when the battery is full to prevent overcharging.