At the time I was barely getting interested in "things" I was likely 9-10 years old, our old old neighbor across the street had a big old "farm" console battery radio He gave me the battery out of it one time. The filament "A" battery section would go dead long before the "B and C" sections were used up. He used to use a 6V car battery with screws driven into the connecting straps to connect, so it may have been 2.5V filaments. it was a BIG battery seems to me over a foot long, and of course tall enough for the big telco cells tall
I believe my old friend was K.P. Dooley, born in 1833, so about 1960 when I knew him he was 77. He seemed a lot older, and was in bad shape, bad lungs and heart. He used to sit in the kitchen in a rocking chair and a blanket over the kitchen door, heated by the wood range.