My RV air conditioner runs all afternoon and the cabin stays warm. Is that normal in a north Alabama summer?
Hot, humid afternoons make a roof air conditioner work hard, and some cooling loss is normal when the sun is on the roof. A unit that never catches up can still have a dirty filter, a weak capacitor, low refrigerant or restricted airflow. It depends on the model and the conditions, so the first step is working out which of those applies before anyone replaces a part.

