Rick,

I have an Engel unit and LOVE it! I have had 2 other portable units and they all used much more power. I was able to make ice in the Sea of Cortez, during the summer! For a sample of actual usage/running amps of one you might want to watch our mini op-eval of our energy monitor on Youtube. It's at;
http://www.youtube.com/watch?v=JUJ0o3SO1y0&feature=share&list=UUyGH1-xOhCotpV_zhSzQq7g&index=3

It was done to show the gauge, but at around 9.5 min into it I show the gauge reading the draw of the Engel unit. Hope this help.

Greg