Change the default output for the datetime list used by EE to display a date range, add this file to your theme/child themes root directory.

content-espresso_events-datetimes.php

<?php
//echo '<br/><h6 style="color:#2EA2CC;">'. __FILE__ . ' &nbsp; <span style="font-weight:normal;color:#E76700"> Line #: ' . __LINE__ . '</span></h6>';

if ( is_single() || ( is_archive() && espresso_display_datetimes_in_event_list() ) ) :
global $post;
do_action( 'AHEE_event_details_before_event_date', $post );
?>
	<div class="event-datetimes">
		<?php 
		//espresso_list_of_event_dates( $post->ID );
		$date_format = apply_filters( 'FHEE__espresso_event_date_range__date_format', get_option( 'date_format' ));
		$time_format = apply_filters( 'FHEE__espresso_event_date_range__time_format', get_option( 'time_format' ));
		$single_date_format = apply_filters( 'FHEE__espresso_event_date_range__single_date_format', get_option( 'date_format' ));
		$single_time_format = apply_filters( 'FHEE__espresso_event_date_range__single_time_format', get_option( 'time_format' ));
		
		echo espresso_event_date_range( $date_format, $time_format, $single_date_format, $single_time_format, $post->ID );
		?>
	</div>
	<!-- .event-datetimes -->
<?php
do_action( 'AHEE_event_details_after_event_date', $post );
endif;
?>