Re: What was an "A" Cell?
An A cell is 17mm in diameter and 50 mm long. Only ever seen rechargeables, and 18500 Lions.
A B cell is 20mm in diameter and the same length as a D cell.
Only ever seen primary cells - and those only in the 4.5v "flat" cycle lamp battery. "BF" cells were about 35mm long and marketed by Eveready as the 927, or in pairs as the No8. A protected 18670 is a reasonable, if higher voltage, substitute for the latter.
C and D you know.
E cells were the same diameter as a D cell, but intermediate between a D and F cell in length. Again, only ever seen primary cells, were used in the Eveready 701 3v cycle lamp battery, and the English 126 4.5v battery.
Completely obsolete.
F cells are the same diameter as D, but about 90mm long. Primary cells used in lantern batteries, rechargeable cells are big enough to use as traction batteries. Oh how I wish they were cheaper.