Passive coolboxes

A passive coolbox does not use any electricity. It insulates well and relies on ice or cooling packs to keep contents cold. The better the insulation, the longer the cooling lasts.

They come in a wide range of sizes. Smaller ones are perfect for picnics and day trips. Larger ones get used for festivals, fishing trips, camping weekends, and anywhere you need to keep a decent quantity of food and drink cold for a few days. Some high-quality models are marketed with impressive ice retention claims of several days or more, and those claims can be accurate — but only if you use them correctly. To get that kind of performance, you need to pack the coolbox with as much ice as possible, filling every gap around the contents. A bag of ice loosely placed on top will not do it. The more ice relative to the contents, and the colder everything starts out, the longer it lasts.

A passive coolbox works well when:

• You are on a short trip and can refresh the ice when needed
• Everything going in is already pre-chilled
• There is no electrical load on the leisure battery to worry about

Once the ice melts, cooling stops, and in warm weather that can happen faster than expected.

Passive coolboxes are best suited to day trips, occasional use, and situations where ice is easy to source. For anyone who needs reliable cooling over a longer period without restocking ice, a powered option will serve you better.