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What Is a Power Inverter? – How Does It Work? | Do You Need One?

Last Updated: August 8, 2022
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power inverter in a car dash

A power inverter is a device that accepts direct current (DC) as an input and transforms it to alternating current (AC).

This AC output can be used to power electric items such as appliances, lights, stoves, refrigerators, TVs, laptops, and so on. You must connect this inverter to a battery and plug in the AC gadget that you intend to use.

To use an inverter as a portable power source, you must first grasp its operation and application. The inverter is an excellent instrument for obtaining AC power from a DC output battery at any time and from any location.

Working of A Power Inverter

When you look at the graph of DC power output, you will notice that it is a straight line. This straight line illustrates the unidirectional, continuous flow of electric charge.

how power inverters work?

The AC source, on the other hand, has a variable charge flow that changes direction every half cycle. As a result, the graphical depiction of AC power output is a sine wave with identical breadth and height peaks.

Power inverters are designed to take DC power as input and then push it to change the direction of charge flow via a physical system.

Inverters transform the DC power supply to AC power. However, these are rough oscillations that, when represented graphically, produce a square waveform.

While standard AC waves are normally circular, these inverters are equipped with filters that smooth the waves. This AC source is compatible with a wide range of electronic devices.

Common Sizes

These power inverters are typically available in three sizes: 1000 watts, 3000 watts, and 5000 watts.

Among these three possibilities, a 3000 watt inverter is the most commonly utilized, providing ideal power output. A 3000 watt inverter is neither excessively powerful as a 5000 watt inverter nor too weak as a 100 watt inverter; it is just the best option for general use.

There is a 3500 watt option for those who want a little extra power. Consider the amps and watts of the appliance you wish to run before deciding on the size of your inverter (you will find this information labeled in the product description segment).

If you want to be on the safe side, go a little higher than your predicted power range (usually, buy an inverter with 20% more power than your highest load).

Determine Peak (Starting) and Continuous Load: It is critical to calculate the amount of power required to run any appliance or tool (essentially any combination of several tools operating concurrently) to start (start load), followed by continuous running (continuous load).

Types of Power Inverters

Power Inverters for Hospital Carts

Inverters designed for use with medical equipment are added to mobile medical carts at several healthcare settings. The usage of these inverters enables health professionals and technicians to follow their treatments, perform diagnostics, and use their specialized equipment without difficulty.

A UL 60601-1 compliant inverter is required for hospital and medical equipment.

Power Inverters for Ambulances/EMS Vehicles

As a portable power source in EMS equipment/ambulance, many specific inverters are entirely reliable and safe. A UL 458 certified inverter will function flawlessly in medical vehicles. 

Power Inverters for Sensitive Electronics

Several electronic devices, such as ATMs, variable-speed tools, laser printers, audio-video components, active PEC-powered computers, and networking equipment, operate on alternating current in pure sine waveform. Microprocessor-controlled and reliable sine-wave power sources help your gadget run cooler and last longer.

You can ensure safety against any malfunction or loss of performance by using a reliable power source.

Ratings of An Inverter

An inverter’s ratings are a reflection of its power output.

Inverters are commonly rated in watts of power, which is determined by multiplying the current in amperes by the potential drop. Various tests are performed on the power inverter, including AC input voltage, frequency, IMD, and others.

The ratings of an inverter are:

  • Continuous Rating
  • Limited-time Rating
  • Surge rating
  • 30-Minute Rating

Some of these tests are required, while others are encouraged. First, the alternating current input is thoroughly checked to guarantee that it will not overheat or damage any attached devices.

The DC output voltage is then tested to confirm that the power provided by the inverter is sufficient in the event of an emergency. Finally, using a particular multimeter and external test equipment, the output voltage and frequency are evaluated on a low level.

Surge Rating

The most essential and often used test of a power inverter is its surge rating.

This rating represents an inverter’s maximum capacity to manage the amount of current or voltage necessary when it overheats, catches fire, or experiences an electrical failure. Because most electrical equipment are not powerful enough to manage surges, an inverter must be.

However, they have sufficient capacity to handle average daily use.

A power inverter’s surge rating refers to how much power an inverter can manage when operating at high voltage or high current levels for a short period of time—typically less than 10 seconds.

Continuous Rating

The continuous rating is the amount of wattage that a power inverter can output without failing continually. The continuous rating does not imply that you can connect and use it indefinitely.

When using such inverters, there is no need to be concerned about overheating or destroying anything. It will damage your appliances in some circumstances, and it may even ruin your inverter in others.

Before utilizing a device with an inverter, it is best to examine its specs.

Limited-Time Rating

The amount of power that an inverter can continually generate for a limited amount of time is referred to as its limited-time or surge rating.

It is also known as an inverter’s duty cycle. The duty cycle is affected by a variety of elements, including the state and condition of the device, the type of load connected to it, the external temperature, and the type of battery connected to it.

Duty cycle ratings are expressed in percentages, with 100 percent duty cycle indicating that there are no restrictions on utilizing an inverter. 

30-Minute Rating

This rating is a critical test. It specifies the maximum power an inverter can provide for 30 minutes.

If any appliance connected to an inverter fails to function properly for more than 30 minutes under normal settings, the power inverter has failed and must be replaced or repaired. It is critical to realize that there is no guarantee for these gadgets, so if damage occurs, there is little you can do.

Frequently Asked Questions

Do Power Inverters Drain Car Batteries?

To put it simply, yes, it is possible.

However, if you delve deeper, you will discover that this process is far more complicated. Assume that the battery you’re using is in good condition and fully charged.

Using 400W batteries in such settings allows you to totally drain the battery without starting the automobile.

It’s time to undertake some mathematical calculations if you want to get more precise and find out how long a battery will survive with any certain inverter.

Begin by dividing the wattage of the inverter you’re using (400W) by the voltage of the specified battery (12V). You will receive the amps drawn by your battery.

In this situation, we get 33.33 amps by dividing 400W by 12V. However, when it comes to transforming power, every given inverter is only 90 percent efficient.

This means that the 400W inverter here is drawing 37 amps.

A typical automotive battery has 80 minutes of reserve capacity (at 25 amps), as is common. In our case, the 400W inverter is consuming 37 amps, which implies it will take around 54 minutes ((80 minutes x 25 amps)/37 amps = 54 minutes.) to totally drain the battery.

This is why it is advisable to start your car’s engine approximately every 30 minutes when utilizing a power inverter, since it will keep the battery charged.

Can I Use My Vehicle and A Power Inverter to Power My House?

Without a doubt! The first step is to determine the wattage of all your electrical devices, calculate your daily wattage, and then purchase a unit capable of handling that amount of energy.

It will undoubtedly help you find the best inverter for your home while also saving you money. Because inverters are not waterproof, keep them away from dust and direct sunlight.

You can quickly connect your inverter to the vehicle’s battery by purchasing jumper cables and alligator clips from the online store. A ring terminal that fits securely over the inverter’s post is another method for connecting the inverter to the car.

Connect the appliance to the inverter with a 200-foot-long extension cord. An extension of this length, on the other hand, will result in significant signal loss.

It is best to run your car for 10 minutes every hour to keep the battery charged.

In this manner, the inverter will continue to function even if the vehicle is turned off (if the battery has not been exhausted).

What Kind of Battery Should I Use with My Inverter?

In general, 12V batteries used in automobiles are chosen for use with standard power inverters.

Furthermore, there are other battery versions on the market, including 24v, 36V, and 48V. Huge-power batteries, on the other hand, have uses in heavy-duty industries where high wattages are required.

If you are looking for a battery to use with your inverter, make sure that the voltage capacity of the batteries matches that of the inverter.

Another alternative is a deep cycle battery, which is nearly equivalent to a standard car battery. A deep cycle battery, on the other hand, will provide you with a longer runtime and uninterrupted operation until the battery reaches 80 percent capacity.

Using a deep cycle battery with an inverter is your best bet for inverter batteries for boats, RVs, or off-grid renewable energy sources. The best thing is that these batteries provide continuous power assistance all the way up to zero battery level, where they may be recharged again.

A battery alone will not suffice, and you will require additional components such as a fuse and its holders.

The ANL fuse is the ideal option because it can be readily used by splicing it into the positive wire of the battery pack.

What Type of Cable Should I Use to Connect Batteries?

When you buy an inverter, there is no connection cord included.

As a result, you must select a cable type that is less than 10 feet long. If you want better results, use SGX cables to connect your batteries to your inverter.

The SGX cable connects and grounds a car’s battery to its electronic system.

What Is the Difference Between an Inverter and A Generator?

Generators can produce electricity using gasoline, diesel, or propane. Alternating current (AC) is required by tools, electronics, appliances, and other equipment, which can only be supplied by an inverter.

When large amounts of electricity are required over a long period of time, a generator may be a better option. An inverter/charger is a better solution in terms of cleanliness and environmental friendliness.

It is suitable for use indoors or in residential areas due to its low noise and lack of harmful emissions. If you have a generator, an inverter/charger will save you gas by shutting it down for short periods of time while keeping your equipment running.

Does an Inverter Provide Surge Protection?

Yes. Because an inverter converts DC electricity to AC power, its AC output is pre-conditioned before it reaches your equipment. Using an inverter, which provides steady output voltage and frequency, you can protect your equipment from power spikes and line noise interference.

Is an Inverter Capable of Powering a Refrigerator or Freezer?

Yes, but don’t overlook one critical point. When a refrigerator or freezer starts up, it consumes a large amount of electricity, several times the watts required for continuous operation. Check the surge capacity of your inverter.

Before installing one, be sure your inverter can handle a peak surge of 500-750 watts for a refrigerator and 500-1000 watts for a chest freezer.

I am a mechanical engineer with years of experience working on Internal combustion engine and fixing electrical and mechanical systems, generators, transfer switches, and equipment related to storm water and sewage pumping stations.