[Raleigh]

If the battery is internal, as with a portable radio, the schematic will probably give a model number of an Eveready or Ray-O-Vac battery that is recommended. Sometimes the "A" and the "B" batteries are separate, but more often radios use an "A/B" battery to supply both voltages.

Usually the schematic will also say what "B" and "A" voltages you need. Sometimes they don't say, so you have to guess from the voltages of the recommended Eveready, Ray-O-Vac, or Mallory batteries.

You can find dimensions of these portable radio batteries on line and sometimes scans of the covers that you can print out. I use 1/4 inch plywood to make boxes the size of the original battery, and then make the battery internals to match however much room I have.

I'm not sure how this is done on farm radios that are not portable and have external batteries. Presumably you can make the batteries any size you need rather than whatever fits, unless you want to authentically reproduce antique batteries in the correct size.

I've made reproduction portable batteries by putting together enough 9 Volt batteries in series to make up the B voltage, usually 10 of them to make 90 volts. I've used eight 9 volt batteries plus 2 AA cells in series to make 75 volts. Some portable batteries were too small to reproduce with eight 9 volt batteries, so I've used three 22.5 volt batteries + 3 AA cells to make 75 volts.

I buy 9-volt connectors and battery holders from Radio Shack and solder them together in series to put as many in series as I need.

Batteries for the filament supply ("A" batteries) for portable radios are made up of regular 1-1/2 volt alkaline cells in series to make any voltage you need, however many you have room for. Recently I made one with 5 AA cells to make 7.5 volts. I didn't have room for larger cells. Another uses 2 "D" cells in parallel for 1.5 volts, just because I had enough room.

A forum member named "Batterymaker" makes accurate reproduction radio batteries with perfectly printed reproduction exteriors. You might be able to buy an appropriate reproduction battery from him or to get advice for the kind of reproduction battery you need.