When venturing into off-grid living, camping, or mobile refrigeration, choosing the right battery to power your 12V fridge is an important detail that needs addressing. Selecting an appropriately sized battery ensures your fridge runs efficiently without unexpected power failures.
At Inlander Low Voltage, we’ve spent over 30 years helping people find the best power solutions for their cool storage needs. This guide aims to walk you through everything you need to know about 12V fridges, types of batteries and the energy needed to keep them as cool as a cucumber.
Understanding How a 12V Fridge Uses Power
12V fridges operate on direct current (DC) power, typically supplied by deep-cycle batteries. Unlike traditional home fridges, these units are specifically designed for energy efficiency, making them ideal for caravans, campervans, boats, and off-grid setups.
Key Factors Affecting Power Consumption:
- Fridge Compressor Cycles: A fridge does not run continuously; instead, the compressor cycles on and off depending on the temperature setting and ambient conditions. When it comes to cycles, efficiency is the aim of the game.
- Ambient Temperature: The hotter the environment, the harder the fridge works, increasing power usage. If you’re subject to less desirable weather, this isn’t much of a concern.
- Fridge Size & Insulation: Larger fridges and poor insulation lead to higher energy consumption. New units are designed with size, insulation and energy expenditure in mind.
- Battery Efficiency & Voltage Drop: As batteries discharge, their voltage drops, which can impact the fridge’s efficiency.
If you’re new to the world of energy expenditure and consumption, do not worry. Amps measure the flow of electrical current, volts represent electrical pressure, and watts (volts × amps) indicate power consumption. For example, a 12V fridge drawing 3A uses 36W (12V × 3A) per hour.
How to Calculate the Battery Size for Your Fridge
Choosing the right battery capacity requires a basic understanding of energy consumption. You’ll need to calculate how much power your fridge uses in a day and match it to a battery with sufficient capacity.
Step 1: Determine Your Fridge’s Power Consumption
The average 12V portable fridge consumes anywhere between 1 to 3 amps per hour (Ah/h). For example:
- A small 40L fridge uses around 1.5A/h.
- A mid-sized 60L fridge uses around 2.5A/h.
- A large 110L fridge may use up to 4.5A/h.
Step 2: Multiply by 24 Hours
To get an accurate reading of power consumption, consider using the following equations:
- 1.5A/h x 24 hours = 36Ah/day
- 2.5A/h x 24 hours = 60Ah/day
- 4.5A/h x 24 hours = 108Ah/day
Step 3: Consider Battery Efficiency
A lead-acid battery should never be discharged below 50% to prevent damage and reduced lifespan. In contrast, lithium batteries offer deeper discharges, safely using up to 80-90% of their capacity while lasting significantly longer.
Thankfully, batteries have developed significantly over the last few decades and we can expect to receive even better results in the coming years. This is due to the rise of exciting prospects such as solid state batteries and fully optimised solar panels.
Recommended Battery Capacity for 12V Fridges
If you’ve had success in working out the consumption of your fridge, you’ll be well on your way to choosing the battery that is right for you and your vehicle. If you’re still at a loss, it may be worth chatting to a professional or phoning a friend. There’s no shame in asking for help – as getting the right battery can either make or break an excursion.
Fridge Power Consumption | Daily Consumption (Ah/day) | Recommended Battery (Ah) (Lead Acid – 50% DOD) | Recommended Battery (Ah) (Lithium – 80% DOD) |
1.5A/h | 36Ah | 100Ah | 50Ah |
2.5A/h | 60Ah | 120Ah | 75Ah |
4.5A/h | 108Ah | 220Ah | 135Ah |
Best Battery Types for Running a 12V Fridge
Not all batteries perform equally when running a 12V fridge, and choosing the right type can make a big difference in performance and longevity. The most common options include:
Lead-Acid (AGM/Gel) Batteries
Affordable, widely available, and commonly used in off-grid setups. However, they should never be discharged below 50%, as doing so can drastically shorten their lifespan. They are also heavier and take longer to recharge than lithium options.
Lithium (LiFePO4) Batteries
While more expensive upfront, lithium batteries offer better efficiency, a longer lifespan, and the ability to discharge up to 80-90% of their capacity without damage. They’re also much lighter, making them ideal for mobile setups like campervans.
Deep-Cycle Batteries
Specifically designed for sustained energy output, these batteries are far superior to standard car batteries, which are meant for short bursts of power rather than continuous use. Deep-cycle lead-acid and lithium batteries are both great choices for powering a 12V fridge reliably.
How to Choose
Choosing the right battery depends on your budget, energy needs, and how often you’ll be off-grid. Lithium is the best long-term investment, while AGM/gel is a solid budget-friendly choice if managed properly.
How to Calculate the Right Battery Size for a 12V Fridge
- Find your fridge’s average amp draw (Ah/h).
- Multiply by 24 hours to get daily usage (Ah/day).
- Choose a battery with at least twice the daily usage (for lead-acid) or 1.25x (for lithium).
- Factor in additional power needs for lights, inverters, or other appliances.
- Consider solar charging if staying off-grid for extended periods.
- How Long Will a Battery Last Before Recharging?
The runtime of a battery depends on its capacity and the fridge’s power draw. Let’s look at some examples:
- A 100Ah lead-acid battery (usable 50Ah) powering a 1.5A/h fridge (36Ah/day) → ~33 hours runtime before recharging.
- A 100Ah lithium battery (usable 80Ah) powering the same fridge → ~53 hours runtime before recharging.
This means a 100Ah lithium battery could last nearly two full days running a small fridge before requiring a recharge.
Tips to Extend Battery Life and Improve Efficiency for Your 12V Fridge
To get the most out of your 12V battery setup, consider these tips:
- Use a Fridge with Efficient Insulation: Well-insulated fridges retain cold better, reducing compressor runtime.
- Pre-Cool Your Fridge Before Use: Plug it into mains power before your trip to chill it down.
- Keep the Fridge Full: A full fridge retains cold better than an empty one.
- Avoid Frequent Door Openings: Limit how often you open the fridge to keep cold air inside.
- Use a Battery Monitor: Helps track usage and prevents over-discharge.
- Incorporate Solar Panels: A 100W solar panel can generate around 30-40Ah/day, enough to top up most 12V batteries.
Sometimes it’s better to be safe than sorry. If you want the reassurance that you’ll have all the power you’ll need, opt for the higher-quality battery. Cheaper batteries degrade faster and may not hold charge as effectively. If you’re on a budget, it may be worth conducting your research and landing yourself a bargain online.
Why Choose Inlander Low Voltage for 12V Power Solutions?
At Inlander Low Voltage, we specialise in 12V power systems, helping adventurers, off-grid enthusiasts, and mobile fridge users find the perfect battery solution. With over 30 years of experience in refrigeration and power management, we understand what works best for your specific needs.
Whether you’re running a 12V fridge for camping, caravanning, or off-grid living, we offer:
- Contemporary and energy-efficient fridges.
- Expert advice on battery sizing and efficiency.
- Warranties that will ease any concerns.
With a lot of time in the refrigeration game, we know how important it is to keep your produce cool, calm and collected. That’s why we stock a large range of trusted and reputable fridge manufacturers, ranging from conventional fridges, freezers and up to behemoths like larder fridges.
Need the right battery for your 12V fridge? Contact Inlander Low Voltage today for expert recommendations and power solutions tailored to your off-grid adventures!
