The first step in choosing a car cooler is determining the type that you prefer. In general, there are two main categories: portable and built-in. Portable coolers can be used both inside and outside the car, providing flexibility in their usage. On the other hand, built-in devices are designed to be permanently installed in the car, ensuring a dedicated and safety placement.

Types of car coolers

Cooler bag

The simplest type of car fridge design is the cooler bag. These bags resemble classic bags and are constructed using dense synthetic fabric, with thermal insulation material placed between the layers. Cooler bags typically feature a fabric outer lining, external pockets and handles for easy transportation. They operate based on the thermoelectric cooling principle, which will be described below (operating principles of car coolers).

Cooler bags are designed to hold a limited quantity of pre-chilled food.

It is recommended to place chilled or even frozen products in cooler bags since the refrigeration capacity of such models is relatively limited. Cold accumulators, such as gel, silicone, or salt-based ones, can be used to enhance the cooling effect in cooler bags. The topic of their usage warrants a separate article. However, it is worth noting here that it is preferable to place cold accumulators on top of the food inside the bag. This allows the coolness to distribute more evenly and maintain a lower temperature throughout the bag.

Car cooler bags are appealing due to their affordable price and simple design. They are also very convenient for camping. However, these models have a few drawbacks. Their cooling capacity is relatively weak, and they have a limited storage capacity. The volume of cooler bags typically does not exceed 40 L.

Fridge-containers

The most common form factor for car fridges is containers. These devices are constructed with double plastic walls, between which a layer of thermal insulation is laid. To ensure the uniform distribution of cooled or heated air, many containers are equipped with built-in fans in their design.

Containers are the most widely used form factor for car fridges.

The container format has become increasingly popular and is available in a wide range of models. These fridges, which are further discussed in the text under the classification of car fridges based on operating principles, are designed for both stationary installation and portability. They often feature handles for easy transportation. With a wide range of volume options, it is easy to find a container of the desired capacity to suit various needs. Whether it's a compact solution for one or two people or a large container for a larger group, there are options available.

Fridge-containers

Car armrest cooler

A separate type of containers are practical armrest coolers. Car coolers can be installed in various ways. Some models are designed to be placed between the front seats, while others are positioned in the center of the rear seat with fixation by a standard seat belt. These fridges often provide additional comfort for both the driver and passengers, serving as a convenient armrest that can be leaned on.

Car armrest-coolers are intended to be placed in the middle of the rear row of seats or in the gap between the front seats.

Armrest-coolers for cars often come equipped with cup holders and other accessories on their body. When selecting such a model, it is crucial to ensure that the chosen unit is compatible with the shape and size of your vehicle. It is worth noting that armrest coolers typically have a relatively small usable volume, usually not exceeding 25 L.

Built-in models

Built-in car coolers are specifically designed to be permanently installed and are not intended for portability. In most cases, these coolers use compressor technology, similar to classic fridges. They are commonly installed in vans, buses, large trucks, yachts, boats, and motorhomes, seamlessly integrating into the overall design and concept of these vehicles.

Built-in car coolers are a solution for trucks, buses, motorhomes, boats and yachts.

A built-in car cooler is not an inexpensive option and requires a significant amount of space and proper power supply for installation. These models are not widely popular, but they should be considered for specific requirements or situations where they can effectively address particular needs.

Built-in car coolers

Operating principles of car cooler

Thermoelectric (Peltier)

The principle of operation of thermoelectric car coolers is based on the Peltier effect — the generation of a temperature difference on semiconductor wafers when an electric current passes through them. In the cooling mode, thermoelectric plates cool the internal parts while simultaneously heating the external parts. The fan blows over the heat elements and a cooling effect is achieved. When the direction of the current is reversed, the thermoelectric car cooler operates in a heating mode, allowing it to serve as a storage unit for warm food.

Thermoelectric models in container design are the most affordable and unpretentious options for car coolers.

Thermoelectric coolers usually have a container design, where plates with semiconductors are integrated into the front wall of the device's case. These models do not allow for precise temperature control, but they can maintain temperatures approximately 15 — 20 ° C lower than the surrounding outdoor temperature. It is recommended to load pre-cooled products into the thermoelectric container since their cooling capacity is relatively weak. To address the issue of slow temperature rise, it is advisable to turn on the thermoelectric cooler well in advance before the trip or use cold accumulators to cool the chamber.

Thermoelectric car coolers offer several competitive advantages, including their affordable pricing, silent operation, low sensitivity to vibrations and movement. These coolers can be powered by a 12 V or 24 V cigarette lighter socket in the car, while some models also have the option to be powered by a standard household outlet with a voltage of 230 V. This feature becomes useful when parking the car overnight in hotels or campsites, providing flexibility in power source options.

Thermoelectric car coolers

Compressor

Compressor models of car coolers are designed in a similar manner to classic refrigerators. The central component of these coolers is the compressor, which circulates the refrigerant throughout the refrigeration circuit, connecting the evaporator and condenser. The cooling effect is achieved through the evaporation of the refrigerant, typically freon, while excess heat is expelled to the outside through the condenser heat exchanger.

Compressor models of car coolers operate based on the same principle as classic home refrigerators.

Compressor car coolers offer a wide range of volume options, ranging from 18 to 250 liters. These devices not only provide cooling but also have the capability to freeze products. In the freezing mode, the temperature can be maintained at a level of up to -20 ° C, making them suitable for transporting frozen meat, berries, and canning. Compressor models are known for their rapid temperature attainment and ability to consistently maintain the set temperature. Even after the unit is turned off, the low temperature inside can be maintained for 6 to 8 hours.

While the compressor principle of operation may seem optimal for car coolers, it is not without drawbacks. Compressor models tend to be expensive and require high-quality road conditions to avoid the risk of freon leakage from the cooling circuit during bumpy and uneven rides. These models can also generate noise during operation and occupy a significant amount of space. As a result, compressor models are commonly found in the category of built-in car coolers where these limitations are less of a concern.

Absorption

Absorption coolers offer a self-contained option for outdoor trips. These coolers can operate not only using the car's cigarette lighter socket, but also by using a gas cylinder as a power source. The design of absorption coolers relies on an absorber, which serves as a substitute for a compressor, and an ammonia-water solution replaces the traditional refrigerant. The desired temperature is achieved through the absorption process, where ammonia is absorbed by water. Absorption models can cool food by 20 — 30 °C below the ambient temperature, with a minimum cooling level of 0 °C. Some coolers within this category have the capability to cool down to -5 °C.

Absorption-based car coolers are versatile in their power options, as they can operate using both electricity and gas as energy sources.

In terms of speed and overall cooling efficiency, absorption-based models outperform thermoelectric coolers but are slightly less efficient than compressor ones. The design of absorption car coolers is relatively simple, and they produce minimal noise during operation. When powered autonomously by a gas cylinder, these devices can operate for extended periods. On average, a 5-liter gas cylinder can provide about 10 days of continuous operation for the device.

One drawback of absorption car coolers is their susceptibility to rolls, vibrations, and shaking, making them less suitable for use on rough or bumpy roads. However, they are well suited for picnic trips or camping adventures where road conditions are relatively better.

Useful features

Of course, the main function of cae coolers is the cooling of products. But don't discount the heating and freezing modes. The first option is often used as the second mode of operation of thermoelectric coolers, the second is the prerogative of compressor models.

An important auxiliary function of coolers is car battery discharge protection. In order to avoid unpleasant consequences for the driver in case of a critical decrease in the level of charge, the battery monitoring system gives a warning signal or turns off the cooler.

Modern and advanced car coolers support remote control from a smartphone.

The display in car coolers is used to display operating modes, internal temperature, car battery status, etc. With it, you can control the conditions inside the working chamber without opening the device once again. Advanced models even suggest the ability to control parameters remotely — from a smartphone. However, such an implementation is not cheap.

Another useful feature can be called internal lighting. The lighting of the chamber will be useful when you need to find something in the cooler at night.

In the car, the cooler usually occupies the cigarette lighter socket. However, to address the issue of limited available sockets for charging gadgets, many car coolers come equipped with a standard USB connector now. These connectors allow users to connect their smartphones and charge their batteries.

Car coolers with battery monitoring

Design features and optional accessories

Car coolers commonly use removable partitions to separate the internal space. These partitions are often included as standard equipment and are useful for organizing and categorizing different types of products. They are particularly important in single-chamber fridges, which are the most common type available. The partitions allow for the separation of incompatible items, such as meat and desserts or fish and vegetables. On the other hand, in two-chamber models, the compartments are already divided by a fixed and non-removable wall, ensuring separate storage for different types of products.

Removable lid will also be useful. In some models, the lid is removed in order to make it easier to get to the contents and to make the working chamber easier to clean. In others, it is often possible to choose the side in which the lid will recline.

Removable partitions are often used for zoning the space of the cooler chamber.

Carrying handles are an essential feature found in almost all car coolers, providing convenient transportation. Moreover, some models are designed with additional straps that allow users to carry the cooler on their shoulders for even greater convenience. In the case of larger and heavier coolers, they may be equipped with transport wheels, enabling users to transport the unit like a trolley, providing ease of mobility.

In some cases, it may be necessary to acquire a power cable of the appropriate length to connect the cooler to the cigarette lighter socket. An extended cable is often required when placing the car cooler in the trunk or a more distant location within the vehicle. Additionally, some compressor-based models may have the option to purchase separately available thermally insulated protective covers to provide added insulation and protection for the cooler.

How to choose the right car cooler

Choosing the right car cooler model depends on the specific purpose of the purchase, the intended installation location, and the method of securing it in the car. For picnics, cooler bags and containers that can maintain temperatures 15 to 20 °C lower than the ambient temperature are highly suitable. Optimal volumes range up to 30 liters, providing ample space to store snacks for 3 to 5 people. When considering a cooler, it's important to assess not only its capacity but also the shape of the working chamber to ensure it can accommodate items such as 1.5-liter or 2-liter plastic bottles.

For long trips, regular fishing and hunting trips, it is better to give preference to containers that maintain the required temperature for a long time. If you are planning a long trip with a large company, you should buy a more spacious model — with a volume of 30 — 50 liters.

Helpful advice. To correctly determine the required volume of a car cooler, it is recommended to allocate an average of 5 to 10 L per person.

When choosing a car cooler, it is important to consider the dimensions and weight of the appliance and determine the available space in the vehicle. Thermoelectric and absorption models generally weigh around 3-5 kg, while compressor models can be heavier, reaching up to 20 kg or more. If the intention is to install the cooler permanently in the car, weight may not be a significant factor. However, if the unit needs to be frequently removed and repositioned, opting for a lighter model will make handling and transportation easier.