Conductance measurements in relation to battery state of charge

The use of conductance measurements as a means of accepting supplies of valve-regulated lead-acid (VRLA) cells and batteries has been investigated. The results of the work show that in general terms, the technique would not be suitable for supplies acceptance criteria, with more indicative information being available from open circuit voltage measurements. One reason for the given conclusion arises from the fact that new fully charged product has a large tolerance range for conductance values, (typically ±10%). A second reason arises from the effect of the electrolyte conductance upon the measured cell conductance as the electrolyte changes its concentration during operating conditions. An explanation for the electrolyte conductance effect is given in respect of a cell´s state of charge during open circuit and also during discharge conditions