WooCommerce - Change number of related products on product page

gistfile1.php

<?php
/**
 * WooCommerce Extra Feature
 * --------------------------
 *
 * Change number of related products on product page
 * Set your own value for 'posts_per_page'
 *
 */ 
function woo_related_products_limit() {
  global $product;
	
	$args['posts_per_page'] = 6;
	return $args;
}
add_filter( 'woocommerce_output_related_products_args', 'jk_related_products_args' );
  function jk_related_products_args( $args ) {

	$args['posts_per_page'] = 4; // 4 related products
	$args['columns'] = 2; // arranged in 2 columns
	return $args;
}

Thanks issac! Works!

the easiest and best way I found was by using a plugin called Woocommerce booster!, it works like charm. http://wooassist.com/how-to-change-the-number-of-related-products-in-woocommerce/

For me the following worked by setting the priority parameter:

add_filter( 'woocommerce_output_related_products_args', 'cwc_change_number_related_products', 20 );

function cwc_change_number_related_products( $args ) {

$args['posts_per_page'] = 2; // # of related products
$args['columns'] = 2; // # of columns per row
return $args;
}

Thanks Derek, that did the trick with priority. So, I wanted to change the number of products per row and ended up with this:

/* ADD 4 RELATED PRODUCTS */
add_filter( 'woocommerce_output_related_products_args', 'jk_related_products_args', 20 );
function jk_related_products_args( $args ) {
$args['posts_per_page'] = 4; // 4 related products
$args['columns'] = 4; // arranged in 4 columns
return $args;
}

I figured I'd post it here in case someone else is looking to do the same.

+1 for suggesting to add the priority to the add_filter() function. Got it working for me!

add_filter( 'woocommerce_output_related_products_args', 'jk_related_products_args', 20 );