Ford explorer

While driving, the key in the ignition is in the run position. If the engine kills for any reason the battery light may come on. This is due to the system reading the alternator is not charging the battery, as it cannot do if the engine is not running. Since the engine started back up right away, obviously the battery is good. Problem is a mechanic cannot diagnosis a problem unless it is present. About all you can do at this point is have a parts store like Autozone pull any codes which may be in the system.