|Sealed Lead Acid
-This chemistry is the most economical for large applications. Sealed lead acid batteries are easy to maintain and work well when more broad operating temperatures are required. However, these batteries must be stored in a charged state and cycle life can be diminished by a deep discharge. The most important factor when considering a sealed lead acid battery is weight and size. Lead Acid batteries are best in stationary or wheeled applications.
Nickel Cadmium (NiCd)
-One of the most common chemistries for many years, Nickel Cadmium offers a relatively inexpensive rechargeable choice for battery packs. They are typically used where long run times and temperature variances have posed a challenge. However, this battery does have some disadvantages, the best known of which is the “memory effect”, the formation of large crystals on the cell plates. In addition, the NiCd is not the ideal chemistry for an application where the battery is to remain on the charging system for extended periods of time and then used only occasionally. In addition, this chemistry is environmentally unfriendly and recycling procedures need to be followed to ensure the used batteries are disposed of properly.
Nickel Metal Hydride (NiMh)
-In terms of economics, the Nickel Metal Hydride is probably a close third. Modern NiMh batteries offer up to 80% higher capacities than their NiCd counterparts, have less tendency toward the “memory effect” and are more environmentally friendly. Of course, these are not without a trade-off. The NiMh battery offers lower cycle life and requires more sophisticated charging circuits.
Lithium Ion (Li-Ion)
-The fastest growing battery chemistry, Li-ion offers high-energy density in a lightweight package. This chemistry is more expensive than the traditional Nickel based batteries and requires additional safety circuits to ensure voltage, current and temperature remain at a safe level. Along with being lightweight and smaller in dimension, Li-ion cells do not require the maintenance of Nickel based batteries and rarely develop the “memory effect”. Because of safety concerns, Li-ion batteries may be subject to shipping restrictions.
Lithium Polymer (Li-Polymer)
-Like Lithium-Ion, this chemistry has been growing in popularity. Lithium Polymer offers more flexibility in cell size and shape than Lithium Ion. It requires additional safety circuits and may be subject to shipping restrictions similar to the Lithium Ion. Again, the cost is higher than the traditional Nickel based batteries. This is the ideal chemistry when space and weight are a concern.