yes you can....we do it all the time here in summer is AZ...
but remember..the peel will not be crispy...like baked in an oven...but more like a roasted potato....
clean the potatoes you plan on putting in the crock...stab with a knife or fork....spray the crock with cooking spray....and the potatoes...place in crock and cook all day on low....OR spray the crock and wrap the stabbed potatoes with foil and place in crock..
try and use potatoes all the same size...so they all cook alike....