I’ve done 72 hour shortribs in a 40 qt igloo cooler with the Anova v1. I had to prop the lid up because of the unit so I placed cellophane wrap across the open edges of the cooler to decrease evaporation. After the first night the cellophane had sagged under the weight of the condensation to the point that it was floating upon the surface of the water. I left it there for the remaining 2 days. I lost approximately 1 inch of water over the 3 days with that vapor barrier. Didn’t even top it off. Not too shabby.
Ribs weren’t so bad either.