Thanks Mark, I’ll study all this tomorrow. I always check the separate cell voltages as part of my checklist and have used 3.85v +- .02 &3.65v min as a health check before climbing above 5 ft. I don’t know much about the technology but maybe the cells loose their integrity (not sure of the technical term). But I think your right, maybe time to retire these batteries. Bit of a false economy to try to eek out more useage. Thanks for yr thoughts.