• All batteries fall into one of two categories, primary cell and secondary cell.battery image by Aditia Patria Warman from Fotolia.com
  
  All batteries fall into one of two categories: primary cell and secondary cell. Primary batteries can only be used once and secondary batteries can be recharged repeatedly. The type of battery needed to power a particular appliance depends on what needs to powered, cost, rechargeability and availability.
  
  

Lead-Acid Batteries

• In 1859, French physician Gaston Plante invented the lead-acid battery, the first rechargeable battery. They are commonly used to power large machinery such as automobiles, scooters, golf carts, hospital equipment, wheelchairs and large uninterruptible power supply systems (UPS). Lead-acid batteries are recyclable and deliver high power that is inexpensive, safe and reliable. They are simple to manufacture and have low self-discharge rates, which is a chemical reaction in the battery that shortens battery life and adversely affects the charge. Drawbacks include low specific energy (energy per unit mass, which means the batteries are generally large), poor cold temperature performance and short life cycle.
  
  

Nickel Cadmium Batteries

• Nickel cadmium (NiCd) batteries are fast-charging batteries commonly found in two-way radios, biomedical equipment, professional video cameras, power tools and a variety of consumer electronics. The NiCd battery has a long life, is cost-effective and able to perform well in low temperatures and available in a variety of sizes and performance options. The drawback to NiCd batteries includes a high discharge rate and low-energy density (the amount of energy per unit volume). They also contain toxic metals and are harmful to the environment.
  
  

Lithium-Ion

• Lithium-ion batteries are increasingly being used for many applications, especially laptops and cell phones. Lithium is the lightest metal on Earth and has the largest amount of energy for its weight (energy density) which generally is twice as much as a standard NiCd battery. Lithium-Ion batteries also have low self-discharge, high-energy efficiency (meaning not much energy "escapes" from the battery during charging or discharging) and good high-temperature performance. However, they are expensive to produce, subject to transportation regulations, and they have a short shelf life. Lithium-ion batteries come in a variety of sizes and typically last two to three years.