JE>I'm getting old and my memory isn't what it used to be, but seems that
JE>the A battery was round, about 2-3" in dia and about4-6"
tall. Used for
JE>grid bias or filaments I think. 1.5V IIRC.
JE>The B battery was for the plate voltage - 45V - again IIRC.

 That sounds like what I know as the Telephone Battery. The old wall
 telephone in my grandmothers Farm House in Missouri had some of those.
 The ones with the Magneto crank on the side for ringing.
But I don;t recal the Official Designation.
The farmers had a trick to extend the life also. While they bare called
Dry Cells they reqlly require internal Moisture to operate. The VERY hot
Missouri Summer days woudl dry them out .Yuo then took a tin can of the
approprate diameter and drilled some holes in the Site of the
battery. Then Set the battery in the Tin can and fill it with an
alkaline solution.
---
 þ SLMR 2.1a þ This note from El Cajon California USA