STRENGTHENING THE WEAKEST LINK
The Importance of Battery Maintenance

During the last decade, rechargeable batteries have made little improvement in terms of increased capacity. Compared with the vast advancements in areas such as micro electronics, the lack of progress in battery technology is apparent. Consider, for example, a computer memory core of the sixties and compare it to a modern microchip of the same byte count; what once measured a cubic foot now sits in a tiny chip. A comparable size reduction would literally shrink a heavy duty car battery to the size of a coin. Since batteries are still based on chemical processes, a car battery the size of a coin is still some time off.

What research has brought about is a number of different battery chemistries, each offering distinct advantages over the others but none providing a fully satisfactory solution. Today's most common and promising chemistries available are:

• Nickel Cadmium (NiCd) - used for portable radios, cellular phones, video cameras, power tools and some biomedical instruments. NiCds have a good load characteristics, are economically priced and are simple to use.
• Nickel Metal Hydride (NiMH) - used for cellular phones and laptop computers where high-energy is of importance and cost is secondary.
• Sealed Lead Acid (SLA) - used for biomedical equipment, wheel chairs, UPS systems and other heavier applications where energy-to-weight ratio is not critical and low battery cost is desirable.
• Lithium Ion (Li-Ion) - available only in limited supply and presently used for some video cameras, cell phones, high volumes applications . When readily available, this chemistry will replace some NiCds for high energy-density applications, but at a higher cost.
• Lithium Polymer (Li-Polymer) - when commercially available, this battery will have the highest energy density and lowest self-discharge but its load characteristics will only suit low current applications.