sigh...........One more time: From the Stupid Questions Answered Website
Regarding the "B battery":
Before there were "chips", or even transistors, there were devices called vaccuum tubes which performed the same functions. In order to operate, tubes required two voltages: a low voltage to operate the "filament", or "heater", which generated heat necessary for the tube to operate, and a high voltage which actually did the work.
The low voltage battery in portable radios was called the "A" battery. The high voltage battery was called the "B" battery.
You can't find B batteries anymore because there is no need for them. So
there you have it!
Regarding the unanswered question about battery sizes, "B" size batteries were once relatively common. Old type "B" batteries were once used in tube type portable radios. There was also an "A" battery to power the tube filament. The "B" battery had a relatively high voltage - from 22.5 Volts to over 90 Volts. The "A" battery was a lower voltage battery 1.5 Volts to 9 Volts. You can still find these in antique shops.
Why are there no B batteries? There are AA's and even AAA's, C's and D's...but what happened to B?
Please refer to this site for more info (
Building a TransOceanic battery pack), I would really not like to type the whole thing out. The gist is that A and B sized were used in old antique radios. They do exist and are still made by Eveready in 22.5, 45 and 67.5 volt batteries. I have attached 2 pictures, one of an old B and and one of a current production