Hello folks and welcome to ToughAssTools.com! Today’s topic is the same that it has been for the past few weeks: Power Inverters. These are an overall great tool to have especially if you are always on the road or if you are into off-grid living. These inverters can be used to convert your vehicle’s direct current (DC) over to alternating current (AC) energy. AC electricity is what we use in our homes and offices. If you plug an appliance or electronic into your standard outlet you are using AC energy.
A power inverter will hook up directly to your battery on one end. This is where it draws the DC energy from. On the other end you will have one, two, or multiple one-hundred and twenty volt outlets. This is where you will plug-in your appliances. Now today’s question is focused primarily on refrigerators and freezers. Are you able to power these appliances with your inverter? There is not a simple ‘Yes’ or ‘No’ answer to this. Instead we have to look at a variety of factors to determine if the equipment you have AND how you wish to run your power inverter will work for you.
The very first thing we need to do is determine exactly how many watts the refrigerator, or freezer, uses. In some cases the appliance will have the watts it uses right on the label. However, if you find that you are not finding the wattage number there is no need to worry. You can calculate the watts yourself by finding the total amperage draw from the machine. Once you have the amps you can take that number and multiply it times the volts. Volts are the type of plug-in the appliance takes. So, if your refrigerator plugs into your standard outlet then that is a one-hundred and twenty volt outlet. The math becomes amps times volts. As an example, let’s pretend a refrigerator you are interested in uses six amps. We take six amps multiplied by one-hundred and twenty volts for a total wattage use of seven-hundred and twenty watts.
The power inverter you purchase will HAVE to be above that seven-hundred and twenty watts number. I typically recommend going twenty or thirty percent higher then you think you need when it comes to sizing power inverters. This gives you wiggle room in case you miscalculated AND it also gives you the option to add more appliances/electronics down the road if you wish to.
There is one more point there to mention when it comes to sizing your power inverter. As you know refrigerators and freezers use the refrigeration cycle. This is the process of the refrigerant inside changing between gaseous and liquid states again and again. The cold environment is then created by removing the heat. A key part of this operation is the compressor. This compressor however requires quite a bit of energy to initially turn on. Once it has turned on the wattage demand goes down after about thirty seconds. This is known as ‘Starting Watts.’ When the unit has warmed up and begins to run normally it moves to ‘Running Watts.’
In many cases the amount of starting watts can be significantly higher then the running watts. As an example, a typical refrigerator may need one-thousand to fourteen-hundred starting watts. But when it moves to running watts it may only need two to three-hundred watts. It is VERY important that you calculate starting watts into your power inverter sizing. If you neglect to do this then your power inverter may overload as you try to turn on your refrigerator.
The last point to mention here is how long do you wish to operate your refrigerator and or freezer? Is this for a tailgating party? Or a motorhome? Power inverters draw power from your vehicle’s battery and if the engine of your vehicle is turned off then you can only expect your battery to last thirty, maybe sixty, minutes… at most. If your battery dies while running the inverter then you are going to be left with a dead battery that at minimum will need a jump. At worst you may have permanently damaged the battery.
There are two ways to get around this problem. The first is to run your inverter while your vehicle’s engine is on. When the engine is on the alternator will work to charge your battery continually. This will make up for the draw of the inverter and in essence give you unlimited power supply until your engine runs out of gas. While this is great for road trips it doesn’t really solve the problem if you are camping or tail gating.
The other solution is to install a secondary battery for your vehicle. This secondary battery will have to be a ‘Deep Cycle’ battery. Deep cycle batteries are specifically made for long term use. A typical automotive twelve volt battery is NOT meant for long term use. Instead it gives you a short burst of stored power and then the alternator takes over. If these standard batteries fall below ninety percent capacity then you will be in trouble.
Deep cycle batteries on the other hand can last for hours, sometimes days, before needing to be recharged. One of the main reasons here is that they can go all the way down to fifty percent capacity without any damage occurring. When your vehicle is turned back on the alternator will work to charge your standard battery and also your secondary deep cycle battery.
Installing a secondary battery can be a bit tricky. If you are an experienced tinkerer with vehicles the you should be able to handle it by following this guide that I found. However, if you are no as comfortable working on vehicles then I recommend taking your vehicle into the dealership or a local mechanic and tell them that you want a secondary deep cycle battery installed. If you also already have the power inverter purchased you can ask them to install it as well. Otherwise, you can install it after the fact.
So, in summation folks the answer to your question is yes, your power inverter can run a refrigerator or freezer. Just remember that there are a host of considerations and factors that have to be weighed before you can flip the switch and have your refrigerator up and running. I hope this article was helpful.
Thanks for reading,