Explanation: Edison storage cells are a type of rechargeable battery known as nickel-iron (NiFe) batteries. Each cell, when fully charged, has an average nominal voltage of approximately 1.2 volts. This characteristic voltage is specific to their chemistry and is a key difference from other common battery types. For instance, a lead-acid cell, widely used in amateur radio for higher current applications, typically has a nominal voltage of 2 volts per cell when fully charged. Primary alkaline cells (like AA or AAA) start closer to 1.5 volts, while rechargeable nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) cells also have a nominal voltage of 1.2 volts, similar to Edison cells, but use different chemistry. Understanding these specific voltages is crucial for selecting and configuring appropriate power sources for amateur radio equipment.