The main reasons for the shortened ice preservation time in a cooler box can include several factors:

1、Insufficient Insulation: If the cooler box is not well-insulated, heat can seep in through the walls more quickly, causing the ice to melt faster.

2、Frequent Opening: Every time the cooler is opened, warm air enters, which accelerates the melting of the ice.

3、Direct Sunlight: Placing the cooler box in direct sunlight can increase its internal temperature, leading to faster ice melt.

4、Not Pre-Chilling: If the cooler and its contents are not pre-chilled, the ice will have to work harder to cool everything down, reducing its lifespan.

5、Air Space: A cooler that is not filled to the brim allows for more air space, which can warm up and contribute to quicker ice melting.

6、Type of Ice: Large blocks of ice last longer than smaller cubes or crushed ice, which melt more quickly.

To maximize ice retention, it’s important to address these factors by using a well cooler box, minimizing the number of times it’s opened, keeping it out of the sun, pre-chilling the contents, filling it to reduce air space, and using larger blocks of ice.