Choose a long life battery

What is the wear of a battery when using? Is it a mechanical or chemical damage? In fact, it is indeed both. A battery is a perishable product that begins to deteriorate immediately after leaving the factory. Like a spring under tension, a battery seeks to return to its lowest denominator. The rapid aging of a battery depends on the depth of discharge, environmental conditions, methods used to load and procedures or lack of maintenance. The chemical composition of each battery is affected differently by aging and the use that actually,like the thinkpad r61 battery.

In Figure 1, we compare three batteries to be used in mobile communications and we study the chemical composition of each in terms of energy density, internal resistance, self-discharge and length of life expressed in cycles. To simplify the comparison of the internal resistance, we use d80 batterypacks 3.6 volts.

* The internal wiring, contacts and protection circuits are taken into account. Readings vary depending on the loading elements, the charge status and the number of elements connected in series

** The discharge is highest during the first 24 hours and decreases thereafter. Self-discharge increases with the age of the thinkpad t61 batteryand high temperatures.

*** The length of life cycles is based on the use and maintenance procedures. If we neglect to apply periodic full discharge cycles, the cycle can be reduced by a factor of three.

**** The lifetime cycles is based on depth of discharge. A shallow discharge produced over a deep discharge cycles.

Figure 1: Characteristics of Li-Ion, NiMH and NiCd thinkpad t61p series battery in terms of energy density, internal resistance, self-discharge and long life (life in cycles)

As part of an ongoing program of research to find the optimal system battery for wireless applications, Cadex has conducted tests on the life cycles on the batteries in nickel-cadmium (NiCad), nickel -Metal Hydride (NiMH) and lithium-ion (Li-ion) thinkpad t60 battery . All these tests were run on battery analyzers Cadex 7000 Series test laboratories Cadex Electronics Inc.. Vancouver, Canada.

The batteries were fully charged up front, and underwent a series of continuous cycles of charging and discharging. The internal resistance was measured by the method owner Cadex, the OhmTest. Self-discharge was obtained from time to time by noting the capacity loss incurred during a rest period of 48 hours. 53 batteries of different models and different chemical composition have been the subject of the testing program.

During the battery test laboratory, it should be noted that the yield obtained in a protected environment is usually greater than that obtained when the thinkpad z61p batteryis used in outdoors.