BATTERY BOX ON A 308

The opening to the wheel wells is part of the hot air evacuation path for hot radiator air. Those vents on the top of the wheel wells are inadequate to exhaust all the hot air (and while functional are more about design than function, IMHO), and the essentially sealed lower panel of the front fascia precludes a downward exit. Wheel wells are natural low pressure areas due to the spinning wheels therein, facilitating a net flow from the higher pressure areas behind the radiator and under the car to the outside of the car. (Visible as the protruding spray on a rainy day). Not sure why they didn't bother to isolate/close off the battery, as any water coming in the nose can accumulate around the battery tray, which is why I added some drain slots to my lower pan.