Lessons learned in using ohmic techniques for battery monitoring

A joint study was conducted by Lucent Technologies Power Systems and Sprint on the use of ohmic meters in predicting the state of health for VRLA batteries. The first part of the results of the study have been presented in an earlier paper. The second part of the results is presented in this paper, where the effects such as the inter cell connectors, the string size and the number of parallel strings on the online battery ohmic value are studied. These effects can have profound influence on the measured values and can lead to erroneous conclusions in determining the state of health of the batteries. Although ohmic techniques are being used widely in screening the state of health condition of a battery, there is no industry standard in using the technique