Though perhaps not obvious at first glance, extreme environments are a "natural" for wireless, except perhaps for the temperature effect on batteries, since as we all know cold temperature increases the internal resistance and linearly diminishes the capacity. Batteries that provide 100% capacity at 27 °C (80 °F) will typically deliver only 50% at –18 °C (0 °F). In addition, at –20 °C (–4 °F) most nickel-, lead- and lithium-based batteries stop functioning, though NiCd and specially built Li- ion cells are able to operate at –40 °C (-40 °F).
We also know that battery output degrades rapidly when cycled at high ambient temperatures. For example, if a battery operates at 30 °C (86°F) instead of the optimum service life if used at 20 °C (68 °F) or slightly below, the cycle life is reduced by 20%. Then at 40 °C (104 °F), the loss doubles to 40%. If the batteries are charged and discharged at 45 °C (113 °F), the cycle life is only half of what can be expected if used at 20 °C (68 °F).