Everyone should have backup power supply options. When you first start prepping, it can seem overwhelming just to get your EDC together, but that’s why I’m here to help. When it comes to power backups, generators are fantastic. Solar is even better. However, having an inverter, like this one on Amazon, around can help stop your food from spoiling or keep your fans running in the middle of a heatwave.
Always keep at least two backup plans for your needs. Just as you need a bug-in plan and a bug-out plan, or EDC and long term storage, you need more than one power source. Inverters are all too often ignored by preparedness experts because there are more permanent solutions. However, if the roads are blocked, that bug-out-vehicle isn’t going anywhere, you can use the battery to help keep you and your family safe and thriving.
Can I run a mini-fridge off of an inverter? A decent inverter will give you enough juice to run a sixteen cubic foot refrigerator. That’s a full-size fridge, though not a deluxe model. In short, you can run more than just a mini-fridge off an inverter if you have the right one.
Back To Basics
First, a quick lesson in electronics for those who don’t quite understand what an inverter does. Home electric systems and most appliances run off of AC. That’s alternating current, not air conditioning. Batteries are a form of DC or direct current.
To make a battery compatible with an AC device, you need to convert one form of power to another, which is precisely what your inverter does. In short, it turns battery power into useable household-type power. More importantly, it lets you run your appliances off of standard household wiring.
What is Power
Electricity is not complicated despite the myriad of ‘things’ we do with it. Literally, electricity in the DC form is just a flow of electrons around a circuit. It’s called direct current because the flow is constant and runs in one direction.
AC power is a little different. The power, electrons, still flow, but they change direction about sixty times a second. All the electrons in a power cord, for example, are in constant motion. However, they’re not all headed in the same direction, which works pretty much the same as having one continuous unending flow.
You can see where these two types of power might have a problem with one another. They aren’t compatible if you try to jam them together.
Why Do Cars Run Off of DC & Houses Run Off of AC
A battery is a form of DC power. The energy in the circuit when you connect it runs one direction. Hence a car, or remote control, or anything battery powered is a DC device. Our homes aren’t run on batteries because of a fight between two scientists. The swift and dirty version of the story goes something like this:
Thomas Edison wanted to run everything off of DC power. Nikola Tesla, on the other hand, favored AC. Edison tried very hard to discredit Tesla’s ideas, but Tesla was brilliant. Equally important, Tesla had a business partner, George Westinghouse, who ran Westinghouse Electrical Company. Tesla was the brains, but Westinghouse was more than just a businessman, he was better at marketing than Edison. Now our homes run on AC because Tesla and Westinghouse won the fight for the American public’s opinion and faith.
The Inverter’s Job
Making these two very different systems compatible might seem like a magic trick, but it’s not. A mechanical inverter uses electromagnetic switches. These switches turn on and off very quickly changing the direction. An electronic inverter, like the Energizer 4000 from Amazon, uses inductors and capacitors to do the same thing, but more smoothly. In short, they make DC behave like AC, and it tricks your devices into running off a different power supply.
How Much Power
Before you run out to grab the inverter of your dreams, there are some crucial questions you need to ask about your needs. For example, how long can you run your mini-fridge off of a battery and how many cells would it take you to run a mini-fridge for a year? Make a quick list of what you already have, if anything.
Let’s say you stocked up on some car batteries last time you saw a sale. Knowing what sort of mini fridge will run on them longest and what power rating you need on your inverter is a good start. Just an FYI, car batteries aren’t great for running inverters over long periods, more on that in a minute. Alternately, if you have nothing to start with, make sure you choose compatible items.
Running a Mini Fridge
Since they don’t run continuously, you need a reliable estimate of how long your mini-fridge runs in an hour. Use the middle of the day on a hot day and time it each time it runs for 2-3 hours. That will give you a good average. Multiply that by 24 hours to get a maximum daily run-time.
An incredibly energy efficient mini could run as little as 8 hours a day at 85 watts for 680 watt-hours per day. A hundred and ten volt AC inverter would keep that going just fine. Yours will probably vary. Larger and less efficient models typically range from 100-110 watts.
Once you know how many watt-hours you need per day, check your batteries amp ratings. A decent car battery with a 90-hour amp rating can only run about 400v for a couple of hours. That means it’s not a practical solution for longer-term needs, but you could run a mini-fridge like the energy-efficient model in my example for a few hours.
A standard car battery isn’t meant to run at maximum for long. Furthermore, they aren’t meant to discharge fully at all if you can avoid it. Car batteries are intended to give a large current for a short time.
Deep cycle batteries, on the other hand, can give current over an extended period of time. They’re designed for more prolonged use. Deep cycle batteries are a smarter option. You can even replace a gas-powered generator with this system.
The difference is all in the plates. Car batteries, which give that massive burst of energy needed to start a car, use very thin plates. Deep cycle batteries are the opposite, with thicker plates to provide long and consistent power. Additionally, you can use them over and over because they’re made to recharge.
Pro-Tip: Add Solar
If you add a solar collector to help recharge your deep cycle batteries, it changes the game. Rotate between two or more DCBs, and you can keep that mini-fridge running for ages. If you’re looking at a mid to long term solution for running your fridge, then I’d suggest using the solar-deep cycle rotation-inverter combo to get the most bang for your buck. Not to mention it will keep your food from spoiling and your beer cold.
Before you rush off to buy your new inverter, make sure you double-check your power draw on whatever refrigerator you want to use it with. If you plan to use your inverter to run more than just a fridge, you’ll need that information for every device. Do some basic addition to make sure you can run everything you need off of the inverter and power source you have.
Don’t forget about the intermittent nature of your refrigerator. Since mini-fridges don’t run continuously, so you need to know how long yours is actually running each hour. You can end up shorting yourself with the wrong calculation. Learning to use what you have efficiently is one of the best and most essential skills a prepper can possess.
Choose the right batteries and inverter for your needs. Don’t run a full-sized refrigerator if you live alone and only need a few cubic feet for an emergency. The less you use, the more you’ll have and the longer you can survive on your supplies.