Ni-Cd field experience confirms low maintenance and their operating characteristics in telecom applications

For several years, nickel-cadmium (Ni-Cd) batteries have been successfully deployed in outside plant (OP), remote terminal (RT) applications. Data gathered over a three-year period from several trial installations, confirms their performance. Low maintenance and high reliability were primary system-level design factors when considering Ni-Cd for RT applications. The characteristically high temperatures of an RT are most demanding and challenging. With Ni-Cds installed in all areas of the world, the most interesting trial sites are located in the hottest regions of the US. These installations are described and provide the framework to analyze and discuss recommended maintenance and operating characteristics. Data, continuously recorded on site and remotely downloaded, demonstrates low water usage in field applications and confirms recommended maintenance practices. The flooded electrolyte design only requires infrequent, periodic watering. Water usage rates of several trial sites are analyzed and discussed. Other typical maintenance practices, established from many years of operating valve regulated lead acid (VRLA) batteries, are compared with the recommended maintenance practices of the Ni-Cd. The Ni-Cd\´s operating characteristics are established. Full instrumentation at several trial sites, continually measures and records operating parameters. Data gathered concurrently allows interdependent performance characteristics to be compared. Float current trends and how it can be used to detect the health of the battery string is introduced. Also, through lab testing, the question; "Is there a mechanism for thermal runaway in the Ni-Cd?" is answered.