Use of battery ohmic testing to improve network reliability and decrease battery maintenance cost

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While it is well known that ohmic testing results correlate to the capacity of stationary valve regulated lead-acid (VRLA) batteries that are manufactured in North America and Europe, it cannot be assumed that this relationship transfers directly to the batteries manufactured in China by a diverse array of new battery manufacturers. Since stationary battery manufacturing is relatively new to China, different levels of battery quality and consistency are being delivered by a variety of battery suppliers, thereby presenting a challenge to Chinese telecom operators. This paper is a study presenting how ohmic testing can be successfully used by telecom operators in China to maintain and test the health of batteries in their networks, thus makes the maintenance work pertinent and proactive, cost effective and highly efficient. It can also be utilized as a quality assurance tool used both at battery manufacturing facilities in China to improve the quality of batteries manufactured and as an effective acceptance procedure by the telecom operators. China Mobile is one of the largest battery users in the world. Since early 2006, China Mobile has performed thousands of ohmic conductance tests and subsequent discharge tests on batteries and battery strings. These tests were performed to ascertain the consistency between conductance test data and battery capacity as determined by off line discharge testing. Initial analysis of the results indicates an acceptable correlation between conductance and discharge capacity test results. And the application of this relationship will change the traditional practice of battery maintenance work, thus providing significant value for the telecommunications operators. The final conclusion of this project will demonstrate how telecom operators can have better control of the quality of new batteries, and effectively evaluate the performance of the batteries of different model types from different manufacturers. Also, on-line conductance testing can screen out the defective or low performing cells, and can effectively advise the maintenance technicians to take pertinent maintenance action. Meanwhile, the application of the relationship between conductance and capacity will enable the users to make the best use of the batteries while obtaining the required back-up time during their service life. It also provides reasonable indication of the need for replacement of a battery, thus maximizing maintenance efficiency. With the accumulation of conductance testing data and the analysis of it, telecom operators can have more accurate projections of the battery's aging tendency and its life cycle, thus taking the appropriate preventive maintenance actions and proactive purchasing strategy. The whole process will greatly decrease the overall work load and cost investment. With more understanding of ohmic testing and more confidence in the technology Chinese telecom operators will do less discharge testing over time.