[Adding Solar to an Oliver that is set up with lithium batteries but not any solar package.]

Actually considering buying a recent model Oliver with the Lithium battery installed but no solar package.  I have already ordered one with both but I can get this one about 11 months sooner.  I would like to boondock though.

 

[Adding Solar to an Oliver that is set up with lithium batteries but not any solar package.]

How hard is it to add Solar to an Oliver that is set up with lithium batteries but not any solar package.  Also can those portable solar screens be a substitute?