Sleeping in a car with the AC on for a few hours in an open space parking lot should generally be fine and should not cause major damage to your car's engine or battery. However, there are a few factors to consider:
Engine: Running the car's engine to power the air conditioning will consume fuel. Make sure you have enough fuel to run the engine for the duration you plan to use the AC. Running the engine for extended periods of time may contribute to increased wear and tear, but occasional use should not cause significant damage.
Battery: Using the car's battery to power the AC for a few hours should not pose a problem. However, if the car's battery is old or in poor condition, prolonged use of the AC without the engine running may drain the battery and make it difficult to start the car later. To mitigate this, you can periodically start the engine to recharge the battery.
Ventilation: When running the car's engine in an enclosed space, it is crucial to ensure proper ventilation to prevent the buildup of exhaust gases. If you plan to keep the windows closed while the engine is running, make sure there is sufficient airflow to avoid carbon monoxide buildup. It is generally recommended to crack open a window or use a window vent to allow fresh air circulation.
Legal and safety considerations: Before sleeping in your car in a parking lot, especially for an extended period of time, it is important to check local laws and regulations regarding overnight parking. Additionally, consider personal safety and security by choosing well-lit and safe parking areas.
While running the AC in your car for a few hours should not cause significant damage, it's always a good idea to have your vehicle regularly maintained and inspected by a qualified mechanic to ensure its overall health and functionality.