I have a datetime field on a custom entity defined in baseFieldDefinitions(). This has set a default, which should be now. But when saving the entity, i get following error:

Drupal\Core\Database\DatabaseExceptionWrapper: SQLSTATE[22001]: String data, right truncated: 1406 Data too long for column ‘date’ at row 1: INSERT INTO {sale} (uuid, langcode, user_id, name, status, created, changed, date, price, party) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7, :db_insert_placeholder_8, :db_insert_placeholder_9); Array ( [:db_insert_placeholder_0] => 3e25c5cb-0092-42dd-914b-4e4b91bdcf19 [:db_insert_placeholder_1] => en [:db_insert_placeholder_2] => 1 [:db_insert_placeholder_3] => Jupiler [:db_insert_placeholder_4] => 1 [:db_insert_placeholder_5] => 1516504047 [:db_insert_placeholder_6] => 1516504047 [:db_insert_placeholder_7] => 2018-01-21 04:07:06 Europe/Brussels [:db_insert_placeholder_8] => 2 [:db_insert_placeholder_9] => 1 ) in Drupal\Core\Entity\Sql\SqlContentEntityStorage->doSaveFieldItems() (line 878 of /var/www/drupalvm/web/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php).

This is my field definition:

$  fields['date'] = BaseFieldDefinition::create('datetime')   ->setLabel(t('Sale date'))   ->setDescription(t('The date that the sale took place.'))   ->setRequired(true)   ->setDisplayOptions('view', array(     'label' => 'above',     'type' => 'string',     'weight' => -4,   ))   ->setDisplayOptions('form', array(     'type' => 'date',     'weight' => -4,   ))   ->setDisplayConfigurable('form', TRUE)   ->setDisplayConfigurable('view', TRUE)   ->setDefaultValue(DrupalDateTime::createFromTimestamp(time())); 

How are datetime fields supposed to get a default value? If you look at the error, the value it tries to save is ‘2018-01-21 04:07:06 Europe/Brussels’.