Accelerated life testing of valve-regulated lead-acid batteries

Testing of valve-regulated lead-acid (VRLA) batteries presents problems not encountered in the testing of flooded batteries. These include: dryout (loss of water from electrolyte) due to normal valve operation, valve deterioration, and diffusion through the case; lack of access to the electrolyte for polarization measurements; and inability to monitor growth of plates during testing. The authors accommodate these problems by: weighing the cells to determine loss of water and establish the extent of dry-out; adding controlled amounts of water to the cells under test; performing Tafel tests; fitting pressure transducers and monitoring cell pressure; and conducting detailed autopsy on failed cells after testing. The perceived benefits of conducting high temperature accelerated life tests are discussed.<>