Electric Coolers

What an electric cooler does that an ice chest can't

An ice chest doesn't make cold. It slows warming down, and the ice does the real work until it's water. An electric cooler is an insulated box with its own cooling hardware and a power cord, so it keeps pulling heat out as long as it has power.

That one difference changes everything else on the spec sheet. There's no ice in the box, so you get the full capacity for food. One maker's buying guide says ice-free cooling is cleaner and more convenient, and that powered coolers usually need less volume than you'd think. There's no meltwater soaking the bread. There's also a power question that an ice chest never asks: what's it plugged into tonight?

The plain ice chests, the hard-sided coolers, have their own page on coolers. This page is the overview of the powered group. It covers the cooling types, the specs that decide which one fits, and which narrower page to read next.

Three ways a powered cooler makes cold

Every cooler in this group moves heat from inside the box to the outside air. They just do it with different hardware.

Compressor coolers work like your kitchen fridge

A compressor cooler is a refrigerator shrunk to fit a truck. Penn State's energy course describes a refrigerator as a heat mover: refrigerant soaks up heat inside the box, the compressor squeezes it, it dumps that heat outside through a condenser, then it expands, cools and goes around again. Moving heat from cold to warm takes work, and the work is electricity.

The payoff is control. One maker says a compressor box can freeze regardless of the outside temperature, and holds cold or freezing temperatures on the hottest days. You set a number, and it chases that number. Its US listings show ranges down to about -7°F. Compressor models are what people mean by a 12V fridge, a car fridge or a portable refrigerator.

Thermoelectric coolers keep cold, they don't make much of it

A thermoelectric cooler has no compressor and no refrigerant. The same maker's buying guide describes it as using a low-voltage current to heat or chill, and calls the box minimally insulated. A fan helps move the air.

Here's the catch, in the maker's own words: a thermoelectric cooler keeps contents cool rather than cooling them itself, so items have to go in pre-chilled. Its cooling is rated as a gap below the surrounding air. One maker gives up to 20°C below ambient, a 36-degree Fahrenheit gap, on its category page, and more on one current model. Quick ice math: on a 90°F afternoon in a parked car, a 36-degree gap leaves you at 54°F. The FDA wants refrigerated food at 40°F or below.

The upside is weight and simplicity, and the same maker notes thermoelectric coolers can heat as well as cool. Renee says a cooler that also keeps the casserole warm is the first useful gadget I've ever bought. I'm choosing to hear the word "useful."

Absorption coolers run on gas

There's a third type you'll see now and then. One maker describes absorption coolers as running on gas, independent of electricity, with cooling that depends on the ambient temperature. They're rare in this group and mostly belong to RV setups, which have their own page on 12V RV fridges.

What the electric cooler table shows

The table on this page lists the electric coolers and portable fridges we track on Amazon US, compressor and thermoelectric together. Columns come from the makers' spec sheets and, where those are silent, the Amazon listing (marked as listing values): cooling type, lowest temperature, DC and AC power, capacity in quarts, zones, battery protection, a built-in battery, solar input, exterior size and weight. When neither lists a value, you get a dash, not a guess.

What to look at when you pick an electric cooler

These are the specs that actually separate one plug-in cooler from the next, in the order I'd read them.

Cooling type decides almost everything else

Read this column first. A compressor model holds a temperature you set and can freeze. A thermoelectric model follows the weather. One maker's advice is to pick an electric cooler by the ambient temperature you'll use it in, which is a polite way of saying a thermoelectric cooler in a July truck cab is going to have a hard week.

For deer camp in November, either type has an easier job, because the air is already cold. For summer road trips, beach weekends and anything with raw meat, the compressor column is the one I'd filter by.

Lowest temp tells you if it's a fridge, a freezer or neither

The lowest-temperature spec is where a maker says how cold the box can go. Two lines on the FDA's food-storage page make it easy to read: refrigerator at or below 40°F, freezer at 0°F. If the number reaches 0°F or below, the cooler can work as a portable freezer. If it stops in the 30s, it's a fridge. If the maker only gives a "degrees below ambient" figure, it's thermoelectric and the real number depends on the day.

DC input: the 12v cooler question

Almost every electric cooler runs on 12V DC from a vehicle socket, and many compressor models accept 24V too. One maker lists its compressor coolers at 12/24V DC.

What the DC column can't tell you is how long your battery lasts, which is the real question for a car cooler. That math, plus battery protection and wiring, lives on the car fridge page. The short version: a cooler that keeps running after the engine stops is drawing on the battery that starts your truck.

AC power makes it a plug in cooler at the cabin

The AC column says whether the cooler runs from a household outlet. Some models switch over on their own; one maker's product page says its unit runs on 12/24V DC and 110/120V AC with automatic switching that favors AC. Others ship with a separate adapter, or sell it separately.

That matters at a cabin with an outlet or a campground with hookups, because the vehicle battery gets the night off. One maker's FAQ warns against running its fridges on AC and DC at the same time, so it's one cord at a time.

Capacity in quarts goes further without ice

Capacity is listed in quarts (a quart is a quarter gallon). Some makers publish liters; the table converts them. One maker's buying guide says that since a powered cooler holds no ice, a 50 to 75 liter unit is usually enough where a passive cooler would be about 100 liters. Another maker notes that a larger volume uses more electricity.

Zones: one temperature or two

A single-zone cooler has one compartment and one setting. A dual-zone model splits the box so one side can freeze while the other side is a fridge. On one maker's dual-zone unit, pulling the divider out turns it back into a single zone. Dual zone is the whole idea behind the portable fridge freezer page.

Battery protection and built-in batteries

Battery protection is a low-voltage cutoff: the cooler shuts itself off before it drains the battery too far. One maker's buying guide says its coolers monitor input power and switch off on low voltage from a car battery. Some thermoelectric models have it too; one lists a two-stage circuit. If a model doesn't list it, plan on unplugging when the engine stops.

A built-in or attachable battery means the cooler can run with no vehicle at all, for a while. Those are their own category on the battery powered cooler page.

Solar input is about the battery, not the panel

A solar column marked yes means the maker or the listing states solar compatibility. One maker's FAQ is plain about what that means: a panel can't power the fridge directly; it has to charge a battery that runs the fridge. More on panel setups is on the solar cooler page.

Exterior size and weight decide where it rides

Exterior size is length by width by height in inches. Measure the spot in the vehicle with the lid open. Weight is the empty box. A compressor cooler carries a motor and a condenser, so it's no lunch box. The maker of one small compressor fridge, rated at 22 quarts, lists it at 39 lb. Carry it full and add the food. Ask me how I know my back has opinions.

Which electric cooler fits which trip

Here's how the narrower pages in this group split up, so you can skip to the one that matches your truck and your trip.

• Day drives, lunch and drinks: a thermoelectric cooler, with everything pre-chilled
• Multiday trips in a car or pickup: a car fridge, a 12V compressor model
• Camp, cabin and campsite use: a portable refrigerator, any compressor model built to hold a set temperature
• Frozen food, venison and ice cream: a portable freezer, rated to 0°F or below
• Fridge and freezer in one box: the portable fridge freezer, dual zone
• No vehicle, no outlet: a battery powered cooler
• Compressor details and nothing else: the compressor fridge page

My one opinion on this page: an electric cooler is worth it when you'd otherwise be buying ice every day, not for a weekend that has a gas station on the way. The reason is right in one maker's buying guide. It points thermoelectric coolers at day trips, compressor coolers at extended trips with power available, and a plain ice cooler at mid-length trips without power. For two nights at deer camp with an ice run in town, the hard cooler and a pre-chill still win.

Walt's take on the whole group: "It's a cooler with a cord. A cord is just one more thing to forget." He has a point. In his defense, a cord is also the one thing on this list that tells you when it's not plugged in, because the display goes dark.

Setting up a plug-in cooler and keeping it running

A few habits apply to every powered cooler, whatever the type.

1. Pre-chill it at home on wall power the night before, with the food already cold. Thermoelectric models need this; compressor models just work less.
2. Give it air. One maker's manual says to keep the fridge in a well-ventilated area, and a charging-gear maker says to keep it out of direct sun with good airflow.
3. Load it so nothing rattles or tips when the truck moves; the same manual asks for that too.
4. Don't put hot food in. The manual says to let it cool first.
5. Keep the lid shut and open it only when you need to, per the same manual.
6. Clean the seals and the coils. One maker's blog says faulty door seals let cold air out and waste energy, and that cleaning the coils helps the unit run smoothly.

Food safety stays the same as at home. The FDA says to keep refrigerated food at or below 40°F, use an appliance thermometer and not to crowd the box so tightly that air can't circulate. Real talk: a powered cooler that came unplugged at a gas station looks exactly like one that didn't, right up until you open the lid.

Electric cooler safety

Don't store aerosol cans with a flammable propellant in a powered cooler, and keep it away from open flame and heaters. One maker's manual lists both warnings, and notes the compressor and condenser can get very hot while running.

Who should skip an electric cooler

If you hunt from a cabin with a working fridge, you already own the best electric cooler there is. If your trips are one or two nights with ice in town, an ice chest is lighter, cheaper to run and never asks about volts. And if your vehicle stays parked for days with nothing to charge from, an electric cooler without a plan for power turns into an expensive ice chest with thin walls. The thermoelectric ones especially; the maker calls them minimally insulated.

Everybody else: pick the cooling type, then the power, then the quarts. Then enjoy walking past the ice machine at the gas station like you own the place.