I was out over the weekend and stopped off to look at someone’s attic cleaning sale, and ended up with a few miscellaneous radio-related items I’m planning to resell. One of the more interesting items was a lot of a few vintage radio “B” batteries.

They’re extremely old – the bottom is stamped “For best results put in service before April 1929”, and they have several internal voltage taps so it can supply 6, 18 and 22.5V. Four of these batteries had their taps arranged in series combinations to provide the higher voltages for the tubes, up to 90V.