wp_enqueue_script adds only the first script

function banana_scripts() {     
    wp_enqueue_script('grid', get_stylesheet_directory_uri() . '/js/jquery.min.js', null, null);
    wp_enqueue_script('grid', get_stylesheet_directory_uri() . '/js/main.js', null, null);
}   
add_action('wp_enqueue_scripts', 'banana_scripts');

I have the above hook in my functions.php. The first js file gets included, the second not. Is it incorrect to call this function twice or more?

You gave each each script the same handle/id of ‘grid’

Try something like this.

function banana_scripts() {     
    wp_enqueue_script('grid', get_stylesheet_directory_uri() . '/js/jquery.min.js', null,   null);
    wp_enqueue_script('grid2', get_stylesheet_directory_uri() . '/js/main.js', null, null);
}   
add_action('wp_enqueue_scripts', 'banana_scripts');