Will an RV Fridge Work Without a Battery Power? (Explained)

Have you ever wondered if an RV fridge could work without a battery power? Look no more. We´ve got you covered.

We have all heard of 3-way RV fridges that can use propane to keep your food cool for weeks when you are out boondocking. Absorption fridges can free you on your travels to explore those unspoiled places way off the beaten track.

However, you might ask if your RV fridge can run without a battery as well?

RV Refrigerators will not work without a battery because batteries power the control board and facilitate ignition. The control board needs a 12 volt DC battery to control the gas valve. If there is no power, the gas valve will close, and no LP will power the burner required to heat the refrigerant or provide cooling to the system.

That being said, RV absorption fridges do not draw much power when on propane, and your batteries will have to be reasonably low for your RV fridge to stop working.

However, although your fridge might not draw much power, it still requires voltage to operate. If you are seeking an RV refrigerator and wish to find one to suit your RV battery capacity, please read on.

Table of Contents

What Power Do RV Fridges Use?

RV refrigerators may run off a variety of power sources depending on their make and model. The most common power sources are:

AC or alternating current

AC refers to an electric charge that alternates direction along with the voltage in AC circuits, periodically reversing because of the changing current direction.

AC is the power you connect to at a park or home when connecting your RV to your home electrical system.

Many of your home appliances run on AC, and typically, parks provide a 15-20 amp connection to power your RV refrigerator and devices.

DC or Direct Current

DC refers to an electric charge that flows in one direction only and is typically the power one finds stored in your RV batteries.

Because DC is not strong enough to run the larger RV fridges, one would need an inverter to take your DC power and convert it into AC.

LP Gas

Liquified Petroleum Gas or LP gas is made of compressed vapor gases, including propane used to power the three-way RV refrigerator.

The vapor in the LP gas is a byproduct of natural gas processing and refining, where it is compressed into liquid form to use as a gas source.

What Battery Does an RV Fridge Use?

2 Way fridges, otherwise known as 12-volt fridges, work on a compressor system and function exceptionally well in areas of high ambient temperature.

This type of RV refrigerator works on either a 12v battery (DC) or 240v mains power (AC.)

These fridges tend to be smaller than the absorption refrigerators and may strain your coach battery, and require supplemental solar energy to maintain your battery off-grid.

3 Way fridges or absorption fridges run off 12/24 AC, 240v mains power, or LP gas. Although they do not have the cooling power of a two-way fridge, they are more gas efficient and may run on one 9kg gas tank for weeks.

These refrigerators are the choice for those who prefer boondocking and spending time in areas without shore power.

Propane gas is a cleaner-burning gas than gasoline and is odorless in raw form by added with scent for leak detection.

Propane is portable and energy-efficient and may power your RV fridge when boondocking for several weeks, depending on the size and power consumption of the particular model.

How many Amps Does an RV Fridge Draw From a Battery?

The amperage draw of your RV fridge depends on various factors such as size, make and model, and the age of your RV fridge.

Typically, you will find a label inside your fridge that indicates both watts and amperage draw for the particular model.

If you can’t find a label, you can consult your user manual or enquire from the manufacturer online.

Average Amps For an RV Fridge

RV fridges usually have different amp requirements for the various operations of their cooling systems.

The start-up rate is typically the highest amperage draw, followed by the amperage drawn while the compressor is running, defrosting, and when the fridge is idle.

Although amp draws vary between makes and models, the average amperage for your RV fridge should be:

Larger two-door fridges for an RV require 7-8 maps when starting up
Running amperage of a typical RV fridge should be between 2-4 amps
Defrosting amp draw should be between 1.2-2 amps
When the refrigerator is running only the evaporator fan, your draw should be around half an amp.
LP-powered RV fridges will generally require between 3-4 amps to run.

Will My RV Fridge Run Down My Battery?

Top RV refrigerator brands such as Dometic offer fridges with multiple battery protection levels. For example:

Hi refers to a high cut out at 11.8 volts.
Med refers to a medium cut-out of 11.2 volts.
Lo refers to a low cut-out level of 10.1 volts.

The RV fridge has voltage sensors in the refrigerator under load, and when the voltage drops to a certain level, the compressor will shut down to protect your vehicle battery.

Especially those with smaller RVs with smaller battery power should opt for a high cut-out level to preserve their vehicle battery.

Those with bigger rigs with larger batteries may opt for medium cut-out protection. If you have a dual battery system with a secondary battery isolated from the starter battery, you may select the lower cut-out settings in your RV.

How Long Will My RV Fridge Run Off a Battery?

Your RV absorption fridge will run off your battery for around three hours using battery only. However, using propane as well can power your fridge for weeks.

A compressor-style fridge will last roughly 12 hours on batteries and is suited for people who have access to shore or generator power.

What Types of RV Fridges Use a Battery?

If you visit an RV forum, you will find that opinion is very divided regarding which fridge is best for your travels.

“Your refrigerator choice rests on a variety of factors, including where you intend to camp, the size of your RV, and which power source you prefer.”

Although some RV enthusiasts use residential fridges in larger rigs, typically, the best choice for an RV is a fridge made specifically for the road. The main types of RV include:

Compressor RV Refrigerators

A compressor RV fridge is typically powered by AC/DC and can run on shore power if your RV is plugged in or off coach batteries if it is not plugged in.

RV compressor fridges run on a similar system to residential fridges and use a closed-loop cooling system that relies on mechanical gas compression.

Unlike absorption RV refrigerators (explained below), compressor refrigerators typically use hydrochlorofluorocarbons (HCFC) in a system of compression, condensation, and evaporation.

The benefits of a compression-based RV refrigerator are that they tend to offer more space and more consistent cooling than the absorption-based RV fridge and are not affected by altitude.

Residential refrigerators manufactured for fixed environments are also compression-based but rely only on AC power.

These fridges require an inverter for times when you disconnect your RV from shore power. Although residential fridges are gaining popularity in larger rigs, you may damage a residential fridge’s internal components by travel over time.

Absorption Based RV Refrigerators

Absorption refrigerators are a popular choice in RVs and campers because they use an LP gas, DC (battery or vehicle electrical system), or mains power.

Unlike the compression refrigerators systems, absorption fridges have no moving parts other than the refrigerant (typically ammonia or water.)

The absorption fridge’s variety of power options makes them a much more flexible alternative to compressor-based refrigerators. Like compressor-type refrigerators, absorption fridges use a refrigerant gas with a very low boiling point temperature.

In both types of fridges, when the refrigerant reaches a boiling point from a heat source, it then carries away the heat with it as it condenses.

This change between gas and the solid-state provides the cooling required for the contents of your refrigerator.

The main difference between the compression and absorption systems is that the absorption process uses only heat to change the gas back to a liquid and has no other moving parts besides the refrigerant gas.

Can I Run a Residential Fridge on Battery in My RV?

If you plan to use a residential fridge in your RV, you should consider an extra battery pack and stall an inverter to charge the 12v battery charge into a 120-volt power for when your rig is unplugged.

One should also consider solar panels or generators to power your residential fridge in your RV for boondocking or travels off-grid.

One should take care when kitting your RV with a residential fridge as they are manufactured to be stationary and have moving parts that may suffer wear when on the road.

Residential refrigerators also need space and sufficient airflow to prevent overheating, which may be a problem in smaller rigs.

RV fridges have a unique feature to ensure that your fridge will automatically switch over to LP gas for power when you no longer receive AC electricity from either shore power or a generator.

They also have features to keep the fridge securely closed when traveling over rough terrain.

How can I Make Sure My RV Fridge Stays Running?

Don’t overfill your RV fridge as tempting as it might be when you are planning a boondocking. RV fridges need spaces for the cool air to circulate, and an overstocked fridge will not cool as well.
Pre cool your items for travel before you [put them in the RV fridge. Often absorption fridges take several hours to bring the fridge contents to a suitably cool level.
Try and find a shady spot to park your RV when the weather is hot. Ambient temperatures affect how your fridge will operate.
Ensure that your refrigerator roof vent is clear and free of any obstructions or debris.
Turn your RV fridge on before you plan to leave; if you run your fridge for 24 hours before you embark, as they take time to reach suitably cold temperatures.
Keep your RV fridge level to ensure that your gas can flow properly through the cooling unit. Parking on an incline may cause extensive damage to some RV fridges and may even end up wrecking the unit.
Try not to leave your fridge door open longer than necessary as this will bring down the temperature of your fridge. Decide what you want before opening up the doors to shorten the fridge’s exposure to ambient heat.

How To Run RV Fridge On Propane

I found its VERY EASY. Literally just turn on the propane tank. Let the gas flow for a minute. Perhaps light up the stove, to help the gas flow.

Then just simply turn on the power of the fridge. Set it to gas. The fridge will turn on ONLY if there is enough battery power from the deep cycle battery next to the propane tanks.

In my case, these batteries (which are basically car batteries), are behind the propane tanks.

If you do not have battery power, you need to plug in the entire trailer via the cord outside the trailer to a house outlet.

Or the generator if you have one. But be sure to set the refrigerator to gas if you are just testing the propane method of powering the fridge.

How to start up the propane refrigerator on a trailer >> Check out the video below:

Conclusion

Although you won’t be able to run a standard RV fridge off propane alone, absorption fridges designed for RVs draw very little power from your battery when used correctly.

3-way absorption fridges are your best option for longevity and gas efficiency when off-grid, while your 2-way compressor fridges provide superior cooling if you are near a power outlet.

Either way, you can sit back and enjoy your cold beer, whether you are out in the boondocks or an RV resort.

References

https://store-au.dometic.com/