Solar Panels 2

Hi All

After our first season of using our van we decided to upgrade to a brand new one! As part of the upgrade we can have fitted at factory a 120w solar roof panel on the roof as an upgrade! Now being new to using our van we don't mind having one fitted from new if its going to prove right for us? We need to know everyone thoughts on such a bit of kit? what benefits will it give us? etc why would we get one apart from keeping the battery topped up? Is there any other real benefits?

Await all that knowledge out there coming our way!