billarnett
Member
Just as any particle flying through an accelerator (e.g. Large Hadron Collider) becomes heavier when the Accelerator pumps more energy into it (by making it fly faster), same happens with our cars. When you charge it, the energy from the grid becomes stored in the car, and this energy has mass. You can say the mass came through the wire, but it came in form of energy, not matter.
Notice that this energy was taken from the outside world when you charged. Which means the rest of the world became lighter. At some point almost all of it was lost by the Sun: converting Hydrogen into Helium, what it's currently doing, generates a significant mass deficit, which of course flies away in form of radiation energy. This energy got captured here on Earth either by the water (evaporated -> got higher up -> condensed -> melted -> gravity took it down -> spun the turbine in the hydroelectric plant) or by plants (photosynthesis created energy-rich, heavier, molecules that we burned many millions years later -> heated water -> spun the turbine in thermal power plant) or by air (it got warmer one place than the other and started moving to the colder areas -> spun the wind turbine) or by photovoltaic panel. The only exception here is the nuclear power plants that derive energy from extra mass captured in heavy elements generated by supernova explosions that happened in the previous generation stars.
When you drive, most of the energy is lost to air drag. This drag makes the air and the car a little warmer, and therefore heavier. While the battery becomes liter, the world around it becomes heavier as you drive.
The other exception is the tiny amount of energy we capture from geothermal sources. That comes from heat deep within the Earth which is partly derived from nuclear decay and partly just left over from the heat generated from the potential energy of all the mass that fell together during the formation of the Earth.