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What is a Power Inverter and What is It Used for?

Tech - by Bryan Veldboom - updated on 2/9/2022

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There's nothing better than getting away for a long camping trip or a relaxing day on the water, especially when you can take your favorite appliances with you. The batteries in RVs, boats and other vehicles can be used to power things like TVs, microwaves, air conditioners and more. In order to tap into that power though, you need to use a power inverter. Learn everything you need to know about power inverters, including what they are, how they work and what the differences are between modified and pure sine wave inverters.

What is AC Power and DC Power?

In order to understand what power inverters do, we first have to take a look at how electricity works. Different power sources give off different types of electricity. The power outlets in your home give off a standard of electricity known as Alternating Current (AC). The second type of electricity, Direct Current (DC), comes from batteries, solar panels, fuel cells and a few other sources.

Without getting too technical, the difference between the two stems from how current flows within each electricity standard. DC power flows consistently in a single direction, while AC power is characterized by periodic changes in direction. This makes DC power more consistent in the voltage that it delivers. AC power, however is cheaper and easier to create. Plus, it can travel much further distances than DC power.

What is a Power Inverter Used for?

Different types of devices have different electrical needs. Household appliances like refrigerators, microwaves and televisions are manufactured to run on AC power, while digital devices such as laptops, cell phones and tablets require DC power. Ordinarily, that's not an issue, however, problems arise when you need to power a device made for AC power using a DC power source.

The batteries in cars, boats, RVs and other vehicles give off DC power. If you try powering a hair dryer, air conditioner or other AC appliance from your vehicle's power, you'll damage the appliance. This is where power inverters come into play. A power inverter converts DC power to AC power, so that you can safely power appliances from your vehicle battery.

What is the Difference Between a Modified and Pure Sine Wave Inverter?

There are two different types of power inverters: modified and pure sine wave inverters. The two differ in how they convert DC power to AC power. A sine wave is the ideal waveform for the transfer of AC power. Modified sine wave inverters approximate a sine wave by abruptly switching their polarity from positive to negative. The modified square wave that they create is not as smooth as a true sine wave, meaning it's not as efficient as the output of a pure sine wave inverter. Pure sine wave inverters are able to create AC power that very closely matches an actual sine wave, resulting in power that is nearly identical to what comes out of the electrical outlets in your home.

If that's a bit too technical for you, don't worry. The biggest difference between these two is price and efficiency. Modified inverters are the more affordable of the two, but can have a negative impact on more delicate equipment, causing them to behave erratically. They are also not as energy-efficient as pure sine wave inverters and can cause a humming noise with certain devices. A pure sine wave inverter will cost you more, but will provide a better performance for a wider range of devices, including more sensitive equipment.

When Do I Need a Pure Sine Wave Inverter and When is a Modified Inverter Okay?

Modified Sine Wave Inverters work best with simple applications, particularly household and commercial tools, such as: drills, chainsaws, air compressors, heat guns, shop vacs, space heaters and sump pumps. They do not work well with electronic timers, digital clocks or more advanced electronics.

Pure Sine Wave Inverters are a better choice for sensitive equipment such as: refrigerators, microwaves, modern televisions and other appliances, as well as lighting, electronics and medical equipment, such as CPAP machines.

How Do I Calculate What Size Inverter I Need?

Both power inverters and appliances are rated in watts. When shopping for a power inverter, be sure that the wattage rating meets the total wattage of whatever you'll be running through it. Here's where things get a little tricky. Some appliances have a much higher starting surge power for the first few seconds of operation before they settle down to their standard running power. Be sure to select your inverter based on the total starting surge power of the device(s) you plan on using it with. This can be calculated by adding the normal running wattage to the surge wattage. If you plan on running multiple applications through your inverter, you will need to calculate the total required wattage for all of your devices and find an inverter that can handle that amount of power.

Shop Power Inverters at Batteries Plus

Batteries Plus sells power inverters for your RV, auto and boating needs. We also offer replacement batteries for an enormous number of vehicles, including RVs, boats, cars & trucks, motorcycles and so much more. Are you planning a camping trip or other getaway? Read about the best portable charging products. If you're an RV owner, we have a number of helpful resources in our blog, including articles on solar power solutions and 100Ah batteries.

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