Will a Camping Fridge Drain Your Car Battery?

Camping fridges drain your car battery whenever they are connected, and your engine is not running. With most camping fridges or fridge coolers, assuming your car battery is in good condition, you will be good for a single night, and still have plenty of juice to start your car.  If you are staying longer, you have to look at alternatives for powering your cooler. 

We love our fridge cooler and would not like to return to a traditional cooler.  Working out how to effectively power the cooler with no risk to our car battery has taken a while. In this article we will consider:

• Why we love camping fridge coolers
• How quickly a camping fridge cooler will drain the batteries of the most popular cars in the US
• How to safely power a camping fridge cooler

We often mix up the use of camping fridge and camping fridge cooler.  Everything we say about battery drain and charging is the same for each.  As we are all about camping in tents, we think most people will be looking to purchase a fridge cooler.  Camping fridges can be used in a tent but are more suited to an RV or camping trailer.

LiONCooler – Self-contained Battery. Solar Cooler.
CampingSage’s Cooler of the year 2020

Please note: As of Nov 2020 this cooler was not available on Amazon. We will let you know if this changes.

Why a Camping Fridge Cooler is a Good Idea

Whenever we think of camping, we come up with a list of essential items such as cooking utensils, sleeping bags, tents, flashlights, and more. Near the top of the list for me is the provision of a top-class cooler.

Most of us are familiar with ice chest coolers. They are available in an enormous range of sizes and capacities.  The best can keep ice frozen for 10-days or more depending on conditions.

The problem with ice chest coolers is that at least half of the available space is taken up by the ice to keep the cooler cool.  If you want to still have ice at the end of the 10 day mark, you will need to have loaded your cooler with at least 75% ice at the outset.  For a typical 60Quart cooler, that leaves just 15Quarts for your food and drink.

RovR Wheeled Camping Cooler 60
CampingSage’s Ice Chest Cooler of the year 2020

A camping fridge cooler, or a thermoelectric cooler, have the huge advantage of not needing ice to keep the contents cool.  For a 60Quart cooler that means that you can carry 60Quarts of food and drink. 

Fridge coolers work exactly like your home refrigerator and will keep your food and drink to the temperature you set.  Thermoelectric coolers are much cheaper but can only reduce the temperature inside the cooler to 36 to 40F lower than outside temperature.  To keep your food safe to eat (40F or lower) a Thermoelectric cooler is good up to an outside temperature of 80F.

Knox 48Qt Electric Cooler
CampingSage’s Thermoelectric Cooler of the year 2020

Fridge coolers are therefore the perfect answer to:

• Packing enough food and drink for a 5 to 7-day camping trip
• Keeping your food and drink cool
• Ensuring your food never gets too warm for safety

Why a Camping Fridge Cooler May Not be a Great Idea

There are 2 issues why you might not want a camping fridge or fridge cooler:

• They need to have a constant supply of electricity – usually 12V DC or House AC. 
• They are expensive

Fridge coolers are great when plugged into your car with the motor running.  Your food and drink will be kept cold for your journey to your campground.  For a peaceful night’s camping it is not practical to continuously run your car engine. 

Fridge coolers are designed to run on 12V DC.  Most will come with a cigarette socket adapter.  Running a fridge or fridge cooler is going to drain your car battery.  The questions are:

• How quickly will my battery drain
• How long can I safely run my camping fridge from my car battery
• What can be done to power my fridge for the whole of my camping trip?

How Quickly is a Camping Fridge Going to Drain My Car Battery?

The time for a Camping Fridge to drain your battery depends on 3 main factors:

1. The capacity of your battery – measured in Amp Hours (Ah)
2. The average current drawn by your fridge cooler
3. The condition of your battery

Car Starter Battery Capacity

Amp Hours may need a little explanation.  It is a measure of the current (Amps) that a battery can supply over time.  A typical 60Ah car battery could, in theory, sustain a current draw of:

Current (Amps)	Time (Hours)
1	60
2	30
3	20
5	12
25*	2:24

*Reserve Charge (RC) is the time a battery can sustain a continuous current draw of 25Amps.  This is one of the official indicators of the capacity of a car starter battery.  In reality, a 60Ah battery could not sustain a 25A current for over 2 hours.  Typically, a 60AH battery will have an RC of about 110minutes.

To put these current draws into perspective, a travel hairdryer is rated at around 1000w. You will need an inverter to run it. To deliver 1000W power, will need around 100A from you battery. You should never attempt to run a hairdryer from your car battery.

Car starter batteries are designed for one main purpose – to start the car.  They are not designed for fairly low, continuous current drain.  We are not going to join the debate on whether running a fridge from a starter battery can damage the battery.  We have done it for years and, as far as I know, we have never damaged our car battery.

The key is to ensure there is enough power left in the battery to start the car.  In summer, with car and battery in good condition, you can safely use up to 40% of the battery capacity for your fridge.  In winter, or with a car that doesn’t always start well, you should only reckon on using a maximum of 30% of the capacity on running a fridge before you charge the battery.

Top 10 Most Popular US Cars – Battery Capacity

In the US, the capacity of a battery is not always quoted in Amp Hours.  Battery performance is usually quoted in Cranking Amps, Cold Cranking Amps, and Reserve Capacity. That is not much use when trying to calculate for how long you can run your camping fridge.

To help, the table below gives typical battery capacities, including Amp Hours, for the most popular cars currently bought across the US.

For consistency, where there are multiple battery options for each model of car, we have assumed the highest Cold Cranking Amps.

Average Current Drawn By Fridge Coolers

In our roundup on the best fridge coolers we included the typical current drawn by some of the most popular models.  The table below shows how long you can safely run each device from your car battery.

		20Ah Running Time (Hours) per cooler cycle time
fridge cooler	Average Current in operation (A)	20%	30%	40%	Estimated
Alpicool CX50	3.75	26.7	17.8	13.3
ARB 50 Quarts	4.5	22.2	14.8	11.1
Dometic CFX3					18.0
ENGEL MR040F-U1 40 Qt					13.3
Linsion 42 Quart	4	25.0	16.7	12.5
LiONCooler Solar					20.0

Notes on this table:

1. 20Ah is 30% of a 65Ah capacity battery
2. Cycle times are the percentage of time that these coolers are running.  Remember, they are thermostatically controlled – exactly like your home refrigerator.  With high quality insulation, the cycle time of these coolers can be very low.
3. We have assumed that the cooler is not opened during this time.  Opening the coolers increases the cycle times.
4. Cycle times are dependent on outside temperatures.  It would be rare for these coolers to ever reach a 40% cycle time unless exposed to extreme heat.
5. Dometic and Engel provide an average current consumption.  As they don’t provide any figures on current or power during the operation cycle, we have estimated running times based on the quoted, average current consumption
6. The LiONCooler Solar is a special case.  It contains its own battery.  Each battery is claimed to keep the cooler cold for 10 hours.  Each battery takes 4-6 hours to fully charge.  It can be run of your car battery (which also charges its own battery). 

Recharging Your Battery

Run the Engine to Charge Your Battery

Our figures are based on never using more than 30% of your battery capacity on your fridge cooler.  Running your car engine for 30 minutes twice a day is usually more than enough to top up your battery.

Remember, your fridge needs to run 24/7.  It will cycle more frequently in the heat of the day.  Don’t neglect to run your car in the morning and the evening.

Starting your car twice a day gives you early indication of any battery drain problems.  You will quickly notice if the starter seems a bit slow in turning the engine.  If so, run your engine for a bit longer each time.

Solar Car Battery Charger

Running your car engine for extended periods each day may not seem to fit with a ‘back to nature’ camping trip.  Luckily, with modern solar chargers there is an alternative. 

We haven’t used a solar charger but, based on some knowledge of car batteries, we recommend looking for a charger unit that includes a regulator.  The regulator will prevent overcharging and will prevent current reversing through the solar panel should the panel fail.

It is also useful I you can plug in and charge your battery via the car cigarette lighter socket.  Something like the TP-solar 20 Watt 12 Volt Solar Trickle Charger seems to fit the requirement well.

Unlike some solar car battery trickle chargers, the TP-Solar includes “Built-in circuitry will protect your batteries from discharging backwards through your solar panels at night when charger’s voltage is lower, and it will also protect your battery from overcharging when your battery is fully charged during day time”.

Will Running a Camping Fridge Damage My Car Battery?

As we have said, we really don’t want to join an argument about whether or not you will damage your battery by running a fridge cooler.

If you have spent any time looking at this question on the internet you will have seen many people claiming you can damage your car starter battery by running a camping fridge (or other low amperage peripheral) from your car battery.  Instead, you should use a deep cycle battery.

Starter batteries are designed to be able to quickly and reliably deliver lots of current for short periods of time.  You need this to provide the power to turn over your car engine. To maximize the power a starting battery can produce it will be built using thinner plates with a small gap between.  Using thinner plates allows the surface area of the plates in the battery to be increased. More surface area means the stored electrons are more immediately available allowing much more current flow.

When a battery is discharged, small crystals of lead sulfate grow on the battery plates.  In a starter battery, when used for starting a car, the battery is charged immediately after discharge, so the lead sulfate never has the chance to grow.

When used for low current draw peripherals (like a camping fridge), the battery discharges over a longer period.  More lead sulfate has a chance to form before the battery is again charged.  There is a chance that the sulfation becomes permanent. Lead sulfate will decrease the life of your battery.

Deep Cycle Batteries

Deep cycle batteries are designed with thicker, more robust plates.  These plates are more resistant to sulfation and other forms of corrosion while in use.  They do not, therefore, have to be charged immediately after discharge.

Deep cycle batteries can be discharged by about 80% of their rated capacity before charging.  Deep cycle batteries are usually 100Ah and up.  This dramatically changes how long you can expect to be able to run your camping fridge.

Renogy Deep Cycle AGM Battery 12 Volt 100Ah for RV, Solar Marine and Off-grid Applications

Here is the table of the fridge running times from earlier in this article.  We have just increased the Ah available from 20 to 80. Not surprisingly, the time you can run a fridge before charging has also increased by a factor of 4.  In the worst-case scenario, a fridge will run for at least 2 days before the battery needs charging.

		80Ah Running Time (Hours) per cooler cycle time
Fridge cooler	Average Current in operation (A)	20%	30%	40%	Estimated
Alpicool CX50	3.75	106.7	71.1	53.3
ARB 50 Quarts	4.5	88.9	59.3	44.4
Dometic CFX3					72.1
ENGEL MR040F-U1 40 Qt					53.3
Linsion 42 Quart	4	100.0	66.7	50.0
LiONCooler Solar					80.0

Car Starter Battery or Deep Cycle Battery for Camping Fridge?

It looks clear cut.  A deep cycle battery will power the cooler for longer. There is no chance I could damage my car starter battery, and there will be no risk of my car battery being drained.

There are other strong reasons for using a second, deep cycle battery too:

• You can put the battery close to the fridge, so we don’t need long leads to connect it to the car. 
• You can leave it hooked up to the fridge while we use the car.  I am all for hiking but sometimes you just need you car to get away from your camp ground.
• You can pitch your tent further away from the car.  It is not always possible to park the car close enough to the tent to be able to run a lead from the car to the fridge.

So, why do we still often prefer to just hook the fridge up to the car?

Firstly, in all the years we have used our car battery to power our cooler, we have never had a damaged battery. 

Deep cycle batteries are big, heavy, and expensive.  When you are car camping in a Civic or a Corolla, you don’t have that much space to pack all your camping gear anyway.

For a weekend trip it is easier to plug the fridge into the cigarette lighter than it is to setup a deep cycle battery rig.

How to Avoid Draining your Car Battery while Powering your Camping Fridge

Buy a Fridge Cooler With Battery Protection

Most camping fridges or coolers have built-in battery protection.  This works by monitoring the voltage being delivered to the fridge.  This naturally drops as the battery is gradually discharged.  If the voltage being delivered to the fridge drops below set levels, the fridge will provide a warning (LED and audible).  If the voltage exceeds safe limits, the fridge may drop the connection to the battery automatically.

Most fridge coolers have 3 levels of battery protection:  High, medium, and low.  Use high if you have a small car with a smaller battery capacity. Medium is good for most cars.  Low works well if you have a dual battery setup.

Choose the Right Fridge size

When choosing a fridge or cooler, you need to pick one that meets your particular camping needs.  Just remember, larger models will require more power to stay cold.

The F40C4TMP Portable 53 Quart Fridge consumes 60W when running. That is 5Amp current draw on a 12V battery. The 20 Quart model, which will hold as much food and drink as a 40-60 quart ice chest model, consumes 45W or 3.75Amp.

Pack the Fridge Well

It is easier to keep food and drink cold that it is to keep lots of empty space cold. You are going to consume the contents of your fridge during your camping trip.  If you are not filling your fridge, consider adding some large bottles of water. Once cold, these will help moderate the temperature inside the cooler. 

Minimize Fridge Opening

This is a tricky one – particularly if you have younger children.  Any fridge is more efficient if you don’t open the door.  On a hot day, with the water, soda and beer in the fridge, you are going to be opening that door pretty often. 

Just try to minimize the number of times the door is opened.

Make sure your car solar charger is always connected during daylight hours

We have already mentioned solar car battery chargers.  They are a great idea.  Just make sure yours is permanently connected.  It is easy to unplug the solar panel, perhaps to charge a phone or tablet, and forget to reconnect.

Keep the Fridge Cool

No, not lost my mind yet.  We are talking about keeping the fridge or cooler in the coolest part of your tent.  Making sure the environment around the fridge is kept as cool as possible will reduce the cycle times and, consequently, the power consumed.

Use Fridge Covers to add shade and extra insulation.  Keep the cooler away from direct sunshine.  Find the part of your tent that stays the coolest – that’s where your fridge needs to be.

Cool all Items before Embarking on your Journey

Pre-chilling food and beverages before putting them in the fridge makes work easier for the cooler and uses less power.

Shut the lid/door Properly

Take time to carefully drop the cover while ensuring that the latches are closed to restrain air from getting in and out.

Never Do This to Extend Your Fridge Running Time

We often see people recommending that you install an auxiliary switch to make it easier to turn your camping fridge on and off.  The theory is that the fridge is well insulated and will stay cold without power.

Camping fridges operate exactly like your home refrigerator.  They are thermostatically controlled to the temperature you chose.  Power is only used when the compressor is running to reduce the internal temperature.

If you install an auxiliary switch you disable the thermostatic control and run the risk of the temperature rising to unsafe levels.

An auxiliary switch can make sense if you are using a cheaper, thermoelectric cooler.  These coolers run continuously – there is no thermostatic control.  Turning these off for a few hours at night may be the only safe way they can be used with your car battery.

How to Power Your Camping Fridge

Once you have used a camping fridge, you will never want to go back to a traditional, ice chest freezer.  Some people cannot see the advantages.  They have grown up on the ritual of cooling the cooler, packing it with food and drink, and then regularly adding ice.

With a fridge cooler, all the space is available for food and drink.  It is cleaner to use as you never end up with the remains of your food floating in the ice melt water.  Best of all, it is much lighter for a given quantity of food and drink.

The big challenge is, How Do You Power Your Camping Fridge Cooler?

We have discussed 2 options in some detail.  For short trips, and where space in the car is tight, go ahead and hook it up to your car battery.  For longer trips, you could use a deep cycle, camping battery.

Both options have advantages and issues.  Fortunately, there are other alternatives.

Deep cycle camping battery

As we have seen, a deep cycle camping battery can run your fridge for at least 4 times longer than a car starter battery.  Deep cycle batteries are great when used with a solar rig for trickle charging during the day.

Camping Power Bank

There are many camping power banks available.  These range from personal devices. best suited for tablets and phones, up go devices intended to power appliances like a camping fridge.

Devices like PRYMAX Portable Power Station, 300W provide multiple output options and can power a camping fridge, running continuously, for about 5 hours.  Based on a 30% cycle time, it should run a camping fridge for about 16 hours.

16 hour running time is more than enough to run your fridge overnight.  After that, you need to be able to charge your powerbank while still powering your fridge.

Powerbanks are often sold to be used with a solar panel setup such as ROCKPALS Foldable 60W Solar Panel Charger

Remember, the solar charger will also be powering your camping fridge and any other devices you have hooked up.  You may be better served by a 100W Solar Panel to give you the best chance of guaranteeing your power bank is charged ready for use.

Power banks can rival the storage capacity of deep cycle batteries.  As they are Lithium-Ion as opposed to Lead-Acid batteries, power banks are much lighter and easier to transport.  They do take a lot more time to charge than the equivalent lead acid, deep cycle battery.

Inverter-Generator

Many years ago, when we first considered using a camping generator, they were all big, noisy units.  How thinks have changed.

Modern inverter-generators are compact, efficient, and super quiet.  Typical sound output is around 60dB.  That is quieter than normal conversation levels and is inaudible outside of 10 feet.

Camping inverter-generators provide between 2000 and 4000W.  Most will run for 10hours plus on a gallon of gas.

Compact (about half the size of aircraft carry-on bag), and weighing 40-60 pounds, an inverter-generator is our choice for powering our camping fridge.  Just remember to take some gas.

A-iPower SUA2000iV 2000 Watt Portable Inverter Generator is a great choice. Weighing just 46 pounds it is lighter than any deep cycle battery.

Solar power

In the last 5-years, there has been an explosion in the availability of portable solar rigs suitable for camping. 

Solar panels are designed to be used with some form or portable power station – either deep cycle batteries or the lighter, Lithium Ion Power Bank units.

In areas with guaranteed sunshine (the panels will produce electricity without direct sunlight but are less efficient), and if you plan on turning all of your appliances off during the day, solar panels are a great idea.

If you expect to run more than your camping fridge, maybe a tent fan for cooling, and a TV, you will quickly exceed the power available from most solar rigs.  We often have many devices connected and find a solar setup can’t always meet our demands.

Electric hook up

A lot of tent campers don’t know that they can use electric hookups too. 

It is true that most campgrounds only provide electric hookups on RV pitches, but a growing number, including many KOA sites, provide hookups for tents. Check out his article to see why electricity in tents is very safe providing you follow a couple of basic safety precautions.

An electric hookup, if available, is the quickest, most versatile power source.  Just plug in, connect a power strip, and you are ready to go. With up to 50A at 110V to play with, you can power all of your devices with ease.

We’ve tried it and liked it.  There are just so few campgrounds where hookup for tents is available. You have to book your slot long in advance.  That may not be a problem if you plan on using all the facilities of a campground available on a KOA site. 

For us, having to book so far in advance took away the spontaneity of the camping experience. 

LiONCooler – battery powered solar cooler

The LiONCooler brings a new concept to fridge coolers.  It can be powered in 4 distinct ways:

• In-built, rechargeable battery
• AC
• Solar panel
• DC via car socket

It is sold as a solar cooler but you need to purchase the solar panels separately. A minimum of 90W panels are recommended.

While connected to any external power source the cooler will run off that source. The LiON will use any excess current for charging the battery.

We consider the LiONCooler to be a game changer for Camping coolers.  A fully charged battery should provide 10 hours of refrigeration.  Each battery takes 5-6 hours fully charge.  With 2 additional batteries you can have one running the cooler, one on standby, and one on charge.

LiONCooler – Self-contained Battery. Solar Cooler.
CampingSage’s Cooler of the year 2020

Conclusion

There is absolutely no question – a fridge cooler will drain you car battery. On average, fridge coolers will draw 4.5A at 12V. As they are thermostatically regulated, you can expect the compressor to be running about 25% of the time. Therefore, you can safely run a fridge cooler from your car battery for about 18hours before you are likely to be unable to start your car.

For a one or 2-day trip, running your fridge cooler from you car is perfectly feasible. You should make sure you run your engine for 30-60 minutes each day to replace the charge your have used.

For longer trips, you will need alternative, more flexible options for powering the cooler. It is not always possible to park you car close to your tent so it is a good idea to have alternatives available, even for shorter camping trips.

Our preferred option is a modern inverter-generator linked to a camping powerstation/powerbank. Many people now use solar panels with a camping powerstation. We just feel that an inverter-generator provides more, immediate power.

Last update on 2024-11-17 / Affiliate links / Images from Amazon Product Advertising API