the NiFe battery is equal to or greater than 1.6 volts per cell. The inclusion of lithium hydroxide improves the performance of the cell. The equalization charge voltage is 1.65 volts. History Swedish inventor Waldemar Jungner invented the nickel–cadmium battery in 1899. Jungner experimented with substituting iron for the cadmium in varying proportions, including 100% iron. Jungner discovered that the main advantage over the nickel–cadmium chemistry was cost, but due to the lower efficiency of the charging reaction and more pronounced formation of hydrogen (gassing), the nickel–iron technology was found wanting and abandoned. Jungner had several patents for the iron version of his battery (Swedish pat. Nos 8.558/1897, 10.177/1899, 11.132/1899, 11.487/1899 and German Patent No.110.210 /1899). Moreover, he had one patent for NiCd battery: Swed.pat No. 15.567/1899. In 1901 Thomas Edison patented and commercialized NiFe in the United States and offered it as the energy source for electric vehicles, such as the Detroit Electric and Baker Electric. Edison claimed the nickel–iron design to be, "far superior to batteries using lead plates and acid" (lead–acid battery). Edison had several patents: /1901, /1902, and German patent No 157.290/1901. Edison was disappointed that his battery was not adopted for starting internal combustion engines, and that electric vehicles went out of production only a few years after his battery was introduced. He developed the battery to be the battery of choice for electric vehicles, which were the preferred transportation mode in the early 1900s (followed by gasoline and steam). Edison's batteries had a significantly higher energy density than the lead–acid batteries in use at the time, and could be charged in half the time; however, they performed poorly at low temperatures, and were more expensive. Jungner's work was largely unknown in the US until the 1940s, when nickel–cadmium batteries went into production there. A 50 volt nickel–iron battery was the main D.C. power supply in the World War II German V-2 rocket, together with two 16 volt batteries which powered the four gyroscopes (turbine powered generators supplied A.C. for its magnetic amplifier driven servomechanisms). A smaller version was used in the V-1 flying bomb. (viz. 1946 Operation Backfire blueprints.) Edison's batteries were profitably made from about 1903 to 1972 by the Edison Storage Battery Company in West Orange, New Jersey. In 1972 the battery company was sold to the Exide Battery Corporation, which discontinued the product in 1975. The battery was widely used for