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During the chapter Sandtraps, five car batteries can be found in inconspicuous areas near an abandoned building and a gate made out of recycled materials. The building, a former Resistance base located between a Combine base and Lighthouse Point, is just off of a road blocked by an electric gate. The batteries require the use of the Gravity Gun to pry them out of awkward positions. One battery is already in its place; another one is on a bed; there is one on a tower; another one is in a blue car wreck; and one can be found under a bathtub. The aim of the puzzle is to collect enough batteries to send power to the gate so it will open and unblock the road.
Car batteries also appear in the chapter Anticitizen One, scattered in a tunnel flooded by sewage waste, as well as inside the hood of the cars. Others can also be found later, scattered on the ground.