Everstar portable ac fills the overflow water bucket in one day. Why?

Too much humidity in the air. The more it runs the more condensation it will create and the faster it will fill up.
I set my portable AC on a small stand I made and left the drain plug out so it goes into a pan/bucket that is larger than the internal bucket. It can run longer and is easier to just empty the external pan/bucket. BUT there is nothing to stop the machine if the external bucket is full, so be diligent in checking it and keeping it empty or you will have water everywhere.

Mine does not make it through the night. I am awoken at 3 to 4 am every night to empty the bucket!!!

Air conditioners cause the moisture in the air to condense on the evaporator coil. The water that is created needs to have somewhere to drain. If the unit is in a humid environment, it will create allot of condensation. This kind of operation is not uncommon.