diff -u b/core/modules/datetime/config/schema/datetime.schema.yml b/core/modules/datetime/config/schema/datetime.schema.yml
--- b/core/modules/datetime/config/schema/datetime.schema.yml
+++ b/core/modules/datetime/config/schema/datetime.schema.yml
@@ -7,10 +7,10 @@
     datetime_type:
       type: string
       label: 'Date type'
-    enddate_get:
+    collect_enddate:
       type: string
       label: 'Collect end date'
-    enddate_require:
+    require_enddate:
       type: string
       label: 'Require end date'
 
diff -u b/core/modules/datetime/datetime.install b/core/modules/datetime/datetime.install
--- b/core/modules/datetime/datetime.install
+++ b/core/modules/datetime/datetime.install
@@ -5,94 +5,21 @@
  * Install, update and uninstall functions for the datetime module.
  */
 
-use Drupal\Core\Database\Database;
-
 /**
- * Add 'enddate_get' field to 'field.storage_settings.datetime'.
+ * Add 'collect_enddate' and 'require_enddate fields.
  *
  * Add 'value2' field.
  */
 function datetime_update_8001() {
 
-  // Update field storage for existing datetime fields.
-  $entity_manager = \Drupal::entityManager();
-  $entity_manager->useCaches(FALSE);
-  $change_list = array();
-
-  foreach ($entity_manager->getDefinitions() as $entity_type_id => $entity_type) {
-
-    if ($entity_manager->getStorage($entity_type_id) instanceof \Drupal\Core\Entity\Schema\DynamicallyFieldableEntityStorageSchemaInterface) {
-      $field_changes = array();
-
-      $storage_definitions = $entity_manager->getFieldStorageDefinitions($entity_type_id);
-      $original_storage_definitions = $entity_manager->getLastInstalledFieldStorageDefinitions($entity_type_id);
-
-      // Detect updated field storage definitions.
-      foreach (array_intersect_key($storage_definitions, $original_storage_definitions) as $field_name => $storage_definition) {
-
-        if ($storage_definition->getType() == 'datetime') {
-          if ($entity_manager->getStorage($entity_type_id)->requiresFieldStorageSchemaChanges($storage_definition, $original_storage_definitions[$field_name])) {
-            $field_changes[$field_name] = TRUE;
-          }
-        }
-      }
-
-      if ($field_changes) {
-        $change_list[$entity_type_id] = array(
-          'field_storage_definitions' => $field_changes,
-          'base_table' => $entity_type->getBaseTable(),
-          'revision_table' => $entity_type->getRevisionTable(),
-        );
-      }
-    }
-  }
-
-  $field_spec = array(
-    'description' => 'The end date value.',
-    'type' => 'varchar',
-    'length' => 20,
-  );
-
-  $schema = Database::getConnection()->schema();
-
-  foreach ($change_list as $entity_type_id => $changes) {
-    foreach (array_keys($changes['field_storage_definitions']) as $field_name) {
-      $value_field_name = $field_name . '_value2';
-
-      $field_schema = array(
-        'fields' => array(
-          $value_field_name => array(
-            'description' => 'The end date value.',
-            'type' => 'varchar',
-            'length' => 20,
-          ),
-        ),
-        'indexes' => array(
-          $value_field_name => array($value_field_name),
-        ),
-      );
-
-      $index_spec = array($value_field_name);
-      $base_table = $changes['base_table'] . '__' . $field_name;
-      $schema->addField($base_table, $value_field_name, $field_spec);
-      $schema->addIndex($base_table, $value_field_name, $index_spec, $field_schema);
-
-      if ($changes['revision_table']) {
-        $revision_table = $changes['revision_table'] . '__' . $field_name;
-        $schema->addField($revision_table, $value_field_name, $field_spec);
-        $schema->addIndex($revision_table, $value_field_name, $index_spec, $field_schema);
-      }
-    }
-  }
-
   // Update the storage configs.
   if (!$field_storage_configs = \Drupal::entityManager()->getStorage('field_storage_config')->loadByProperties(array('type' => 'datetime'))) {
     return;
   }
 
   foreach ($field_storage_configs as $field_storage) {
-    $field_storage->setSetting('enddate_get', FALSE);
-    $field_storage->setSetting('enddate_require', FALSE);
+    $field_storage->setSetting('collect_enddate', FALSE);
+    $field_storage->setSetting('require_enddate', FALSE);
     $field_storage->save();
   }
 
diff -u b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php
--- b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php
@@ -74,15 +74,6 @@
 
         $output2 = $this->formatDate($date2);
 
-        // Check if start day == end day.
-        if ($this->getFieldSetting('datetime_type') == 'datetime') {
-          // TODO better logic to split the date and time based on the format.
-          $length = strspn($output2, $output);
-          if ($length) {
-
-            $output2 = substr($output2, $length - 1);
-          }
-        }
       }
 
       // Display the date using theme datetime.
@@ -99,7 +90,7 @@
       ];
 
       // Append on the end date.
-      if ($this->getFieldSetting('enddate_get') && !empty($output2)) {
+      if ($this->getFieldSetting('collect_enddate') && !empty($output2)) {
         $elements[$delta][] = [
           '#markup' => $this->t(' to '),
         ];
@@ -117,7 +108,7 @@
       }
       if (!empty($item->_attributes)) {
         $elements[$delta][0]['#attributes'] += $item->_attributes;
-        if ($this->getFieldSetting('enddate_get') && !empty($output2)) {
+        if ($this->getFieldSetting('collect_enddate') && !empty($output2)) {
           $elements[$delta][2]['#attributes'] += $item->_attributes;
         }
         // Unset field item attributes since they have been included in the
diff -u b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeFieldItemList.php b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeFieldItemList.php
--- b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeFieldItemList.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeFieldItemList.php
@@ -66,7 +66,7 @@
         )
       );
 
-      if ($this->getFieldDefinition()->getSetting('enddate_get')) {
+      if ($this->getFieldDefinition()->getSetting('collect_enddate')) {
         $element += array(
           'default_date_type2' => array(
             '#type' => 'select',
@@ -170,7 +170,7 @@
     }
 
     // Repeat for end date.
-    if ($definition->getSetting('enddate_get') && !empty($default_value[0]['default_date_type2'])) {
+    if ($definition->getSetting('collect_enddate') && !empty($default_value[0]['default_date_type2'])) {
       // A default value should be in the format and timezone used for date
       // storage.
       $date = new DrupalDateTime($default_value[0]['default_date2'], DATETIME_STORAGE_TIMEZONE);
diff -u b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeItem.php b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeItem.php
--- b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeItem.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldType/DateTimeItem.php
@@ -33,7 +33,8 @@
   public static function defaultStorageSettings() {
     return array(
       'datetime_type' => 'datetime',
-      'enddate_get' => FALSE,
+      'collect_enddate' => FALSE,
+      'require_enddate' => FALSE,
     ) + parent::defaultStorageSettings();
   }
 
@@ -51,24 +52,24 @@
    * {@inheritdoc}
    */
   public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
-    $has_end = $field_definition->getSetting('enddate_get');
-    $require_end = $field_definition->getSetting('enddate_require');
+    $collect_enddate = $field_definition->getSetting('collect_enddate');
+    $require_enddate = $field_definition->getSetting('require_enddate');
 
     $properties['value'] = DataDefinition::create('datetime_iso8601')
-      ->setLabel($has_end ? t('Date value (start)') : t('Date value'))
+      ->setLabel($collect_enddate ? t('Date value (start)') : t('Date value'))
       ->setRequired(TRUE);
 
     $properties['date'] = DataDefinition::create('any')
-      ->setLabel($has_end ? t('Computed date (start)') : t('Computed date'))
+      ->setLabel($collect_enddate ? t('Computed date (start)') : t('Computed date'))
       ->setDescription(t('The computed start DateTime object.'))
       ->setComputed(TRUE)
       ->setClass('\Drupal\datetime\DateTimeComputed')
       ->setSetting('date source', 'value');
 
-    if ($has_end) {
+    if ($collect_enddate) {
       $properties['value2'] = DataDefinition::create('datetime_iso8601')
         ->setLabel(t('Date value (end)'))
-        ->setRequired($require_end);
+        ->setRequired($require_enddate);
       $properties['date2'] = DataDefinition::create('any')
         ->setLabel(t('Computed date (end)'))
         ->setDescription(t('The computed end DateTime object.'))
@@ -97,7 +98,7 @@
       ),
     );
 
-    if ($field_definition->getSetting('enddate_get')) {
+    if ($field_definition->getSetting('collect_enddate')) {
       $schema['columns']['value2'] = [
         'description' => 'The end date value.',
         'type' => 'varchar',
@@ -129,21 +130,21 @@
       ),
     );
 
-    $element['enddate_get'] = array(
+    $element['collect_enddate'] = array(
       '#type' => 'checkbox',
       '#title' => t('Collect an end date'),
-      '#default_value' => $this->getSetting('enddate_get'),
+      '#default_value' => $this->getSetting('collect_enddate'),
       '#disabled' => $has_data,
     );
 
-    $element['enddate_require'] = array(
+    $element['require_enddate'] = array(
       '#type' => 'checkbox',
       '#title' => t('Require an end date'),
-      '#default_value' => $this->getSetting('enddate_require'),
+      '#default_value' => $this->getSetting('require_enddate'),
       '#disabled' => $has_data,
       '#states' => array(
         'visible' => array(
-          ':input[id="edit-settings-enddate-get"]' => array('checked' => TRUE),
+          ':input[id="edit-settings-collect-enddate"]' => array('checked' => TRUE),
         ),
       ),
     );
@@ -156,7 +157,7 @@
    */
   public static function generateSampleValue(FieldDefinitionInterface $field_definition) {
     $type = $field_definition->getSetting('datetime_type');
-    $collect_end_date = $field_definition->getSetting('enddate_get');
+    $collect_end_date = $field_definition->getSetting('collect_enddate');
 
     // Just pick a date in the past year. No guidance is provided by this Field
     // type.
diff -u b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
--- b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
@@ -83,12 +83,12 @@
       '#date_part_order'=> $date_part_order,
     ) + $element['value'];
 
-    if ($this->getFieldSetting('enddate_get')) {
+    if ($this->getFieldSetting('collect_enddate')) {
       $element['value2'] = array(
           '#type' => 'datelist',
           '#date_increment' => $increment,
           '#date_part_order'=> $date_part_order,
-        ) + $element['value'];
+        ) + $element['value2'];
     }
 
     return $element;
diff -u b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDefaultWidget.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDefaultWidget.php
--- b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDefaultWidget.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDefaultWidget.php
@@ -89,7 +89,7 @@
       '#date_time_callbacks' => array(),
     );
 
-    if ($this->getFieldSetting('enddate_get')) {
+    if ($this->getFieldSetting('collect_enddate')) {
       $element['value2'] += array(
         '#date_date_format'=>  $date_format,
         '#date_date_element' => $date_type,
diff -u b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php
--- b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php
@@ -52,7 +52,7 @@
       $element['value']['#default_value'] = $date;
     }
 
-    if ($this->getFieldSetting('enddate_get')) {
+    if ($this->getFieldSetting('collect_enddate')) {
       $element['value']['#title'] = t('Start date');
 
       $element['value2'] = array(
@@ -89,7 +89,7 @@
     // DrupalDateTime object at this point. We need to convert it back to the
     // storage timezone and format.
     $properties = array('value');
-    if ($this->getFieldSetting('enddate_get')) {
+    if ($this->getFieldSetting('collect_enddate')) {
       $properties[] = 'value2';
     }
     foreach ($values as &$item) {
diff -u b/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php b/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
--- b/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
+++ b/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
@@ -131,7 +131,7 @@
   public function testEnddate() {
     /** @var \Drupal\field\FieldStorageConfigInterface $field_storage */
     $field_storage = FieldStorageConfig::load('entity_test.field_datetime');
-    $field_storage->setSetting('enddate_get', TRUE);
+    $field_storage->setSetting('collect_enddate', TRUE);
     $field_storage->save();
 
     $entity = EntityTest::create();