The TSP-408L-1 is a 20-cell SUPERPOWER® battery, with a nominal voltage of 25.2 volts, a nominal capacity of 40 Ah and weighs a maximum 76.5 pounds.  The Marathon Super Power  battery is a greatly improved nickel-cadmium (Ni-Cd) battery that features:

• High porosity sintered carbonyl Nickel electrodes utilizing a Nickel-Steel foil substrate for improved current collection and increased cell reliability.
• Long life, durable micro porous polypropylene gas barrier membrane of proven durability in hot oxidizing environment has eliminated the classic “Thermal Run-a-way” problem with early Nickel Cadmium batteries.
• Long life, durable microfiber polypropylene fabric on both sides of the gas barrier provide superior wicking action that enables the electrolyte conductivity to remain high even if the electrolyte level is below the top of the electrodes.
• Ternary electrolyte solution is specifically formulated to provide excellent cell performance over a wide range of temperatures.
• Redundant temperature sensors that can be used to disable battery charging or alert crew of increased battery temperature
• Stainless Steel battery case and cover assembly that withstands corrosion.