Battery radio tubes are designed to be highly efficent. The heaters are typically at 1.4 volts or 2.8 volts to operate from one or two "D" sized batteries (typically referred to as the "A" battery. The plates are typically designed to operate at 67 volts to 95 volts, which is derived from the "B" battery. Typically the batteries used were 47 volts and 67 volts. In some cases a third "C" battery is used for biasing, but this is less common. While regular tubes have a heater rated at 150mA to 500mA, Battery radio tubes are normally operated at 20mA to 50mA of heater current. That can extend battery life significantly. Power output battery tubes are usually around 100mA to 150mA of heater current in order to provide the electron flow needed to operate a speaker. The plate supply and bias supplies are much lower current draw. Usually the "B" batteries last three to four times the "A" batteries. The draw on the "C" bias batteries is usually in the microamp range which means that the batteries would often last nearly as long as the shelf life of the battery.
When considering a tube project that will be operated from batteries, a Battery radio tube should be the first tube type you should consider. If you have lots of portable power available (such as in a car), consider looking at a space charge tube . Space charge tubes draw heavy on heater current, but only need 12 volts for plate operation thus eliminating the need for an additional high voltage plate power supply. For more information on space charge tubes see the Space Charge Tubes document.
A listing of space charge tubes we have available can be found here: Our Space Charge Tube List
You can find the listing of subminiature tubes we have available here: Our Subminiature Tube List
You can find the listing of preoctal tubes we have available here: Vintage Preoctal and Globe/Balloon vacuum tube listings
You can find the listing of older ST octal tubes we have available here: "G" Style Radio tube listings
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