If you want to keep your fridge powered via a battery while you camp or 4WD, you need to understand how to set up a 12V or 24V energy system.
A 12V / 24V power system is a sure-fire way to guarantee a reliable energy supply to your fridge, lights, chargers, kettle, or other essentials while off-grid.
Frequently asked questions we receive include:
- Can I run my fridge off a car battery?
- Can a 12V battery power a fridge?
- Can I run my 12V fridge off a solar panel?
- How long will a 12 volt RV refrigerator run on battery and solar?
We'll answer these questions in this blog to leave you feeling more confident in integrating an auxiliary battery system into your setup.
What do you need for a 12V battery and solar setup?
To get started with a 12V or 24V energy system for your RV or 4WD (or any other extra low voltage application), you'll need the following:
- An understanding of your power needs - start by identifying which devices and appliances you want to run (and for how long) so you can size your system accordingly.
- A deep-cycle auxiliary battery - this is a secondary battery to your car starter battery, and will store energy to power your devices.
- A charging method - you'll need a way to charge your auxiliary battery, such as solar panels or a DC-DC charger connected to your car's alternator.
- A solar controller - if you opt to charge with solar (highly recommended), you will also need a solar controller installed between your panels and battery. This will safely manage the charging process and prevent overcharging.
Read more: DC circuit protection guide
Can you run a fridge off a car battery?
You can run a fridge from your car's starter battery, but we don't recommend it. Doing so risks draining the starter battery, which could leave unable to start your vehicle. This is the last thing you'd want if you're travelling remote.
Instead, it's better to install a second deep-cycle auxiliary battery. Deep-cycle batteries are designed for long, steady discharges. This makes them ideal for powering consistent loads like your fridge. This setup will protect your car's starter battery from accidental depletion.
Read more: Battery isolators explained
Can a 12V battery power a fridge?
Yep, absolutely. Provided that your battery bank is sized properly and has sufficient charging.
Start by calculating your fridge's daily energy use. Multiply its current draw in amps by the number of hours it runs per day to get its daily Amp Hours (Ah). Do the same for all other appliances and add the Ah sums together to find your total daily load.
If your appliances is rated in watts, divide the watts by the system voltage (12V) to convert to amps.
Next, you need to decide how many days of autonomy you want. I.e., how long you want to charge your system to run without charging, or how long you want your system to run if it can't charge. Multiply your daily load by the number of days of autonomy to determine the battery size you'll need.
Be sure to pair your battery with a suitable charging method to keep it topped up, but oversizing your battery bank slightly to allow for days of autonomy is essential for remote, off-grid travel.
Example
If my total daily load is 100Ah and I want three days of autonomy in case of emergency, then my recommended battery bank size is 300Ah.
Total daily load (100Ah) x Days of autonomy (3) = Battery size (300Ah)
Can you run a 12V fridge off a solar panel?
Yes, you can definitely run a 12V fridge from a solar panel. In a sunny place like Australia, it's an excellent choice of charging method.
Solar panels can keep your auxiliary battery charged as long as you have sized your solar array and battery bank correctly.
Read more: How to calculate how much solar you need for camping & 4WD
To estimate the solar size you need, multiply your fridge's daily load in amps by your battery voltage to get watt-hours. Then, divide by 3.5 peak sunlight hours (3.5 hours is a conservative estimate on peak sunlight hours per day in Australia).
You will also need a solar controller between your solar panels and battery to safely manage the charge and protect the battery's health.
You can choose roof-mounted or portable solar panels, depending on your setup. Both are effective; choose whatever best fits your travel style.
Read more: Best solar panel roof mounts
How long will a 12V fridge run on solar and battery?
If your battery and solar system are sized correctly to your energy needs, your 12V fridge can run indefinitely. Just make sure to account for days of autonomy, i.e. how long you want your system to last if your battery can't charge due to limited sunlight.
For added reliability, it's smart to have more than one way to charge your battery. A DC-DC charger is a great backup, allowing your auxiliary battery to charge from your vehicle's alternator while driving. An extra charging method will help ensure your fridge and appliances stay powered even in cloudy conditions or emergencies.
Read more: How long will it take to charge a 12V / 24V battery with solar?
Wrapping Up
Investing in a 12V or 24V power system is the best way to ensure reliable power while you camp or travel in a 4WD, RV, or caravan. A basic solar-charged power system consists of an auxiliary battery, solar panels, and a solar controller. With even a basic setup, you can power loads like a fridge, lighting, kitchen appliances, and more.
12V / 24V Battery & Solar Systems for 4WD & Camping