content: All electric vehicles come with batter pack heaters built in. Many ICE vehicles also have block heaters which prevent the block from freezing up and breaking. Same concept. The procedure is basically the same. Plug in during cold periods when it won't be driven. It doesn't really change anything. The real down side is that energy density is reduced by the cold and as such range is reduced. Which is further effected by the battery pack heaters and heating elements in the passenger compartment.