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Power Inverter vs Generator

The terms inverter and generator are often used interchangeably due to the similarity in their applications. However, the two machines have different principles of operation and differ in several other aspects like usage and carbon footprint. In this article, we detail the differences between power inverters and generators. In addition, we also discuss different applications where one would be better suited over the other.

What is a Power Inverter?

In simple words, a power inverter is an electrical device that converts DC (Direct Current) power to AC (Alternating Current) power. Most of the electrical appliances we use on a day to day basis like toasters, coffee makers, washing machines, refrigerators and lights run on single phase AC power that is supplied by the wall sockets. Inverters, when connected to 12 V batteries (alternatively, inverters can also be hooked to 6 V, 24 V or 48 V battery banks), can convert the DC power from batteries to AC power suitable for running appliances.  

Inverters with DC outlets can also be used to directly connect cellphone and laptop chargers. This comes in handy when conventional sources of AC power are not available. Thus, power inverters can be used as emergency backup in case of power outages at home or as a source of portable power on the go (think camping trips, hitting the road on a RV or a fishing trip on your boat).

However, it is important to note that inverters are not capable of producing energy on their own. They need a reliable battery supply from which they draw power. If the batteries run out, then the inverter will not be able to operate any device.

What is a generator?

A conventional generator is any device that is capable of converting mechanical energy to electrical energy. Portable electric generators that are typically used in homes run on fuels like diesel or propane. The diesel runs the motor (at about a constant speed of 3000 rpm and an alternator converts the rotational kinetic energy into AC electric supply.

This 120 V AC supply can be used to run common electric appliances. However, direct DC supply is not available. In cases where reliable power supply is needed for an extended period of time, a generator might be a better choice than a power inverter.

Generators do not need additional batteries for power supply. However, they tend to produce a lot of noise and produce fuel exhaust that does not help their environment-friendliness. Let us have a look at how inverters and generators compare to each other on factors like size, weight, portability, efficiency and noise-levels.

Comparison between power inverters and generators

Size and portability: Both inverters and generators can be portable but inverters are generally more compact in size. Generators are bulkier than inverters and need frames or wheels to be mounted. Hence, if you want power for something small like a hiking trip or a night of camping, a power inverter would be your go to option.

Fuel efficiency: Inverters are generally more efficient than generators and can be more compact in size due to the fact that they don’t have large fuel tanks. However, it is important to remember that inverters work in conjunction with batteries and don’t produce power on their own. Inverters are capable of running loads for about 10 hours which is well-suited for most small-scale applications.

Noise levels and  exhaust: The prime advantage that inverters have over generators is the fact that they are much quieter and cause less pollution. Traditional diesel generators produce a lot of noise due to the rotation of the alternator. Burning of fuel also emits polluting fumes. This exhaust is often considered hazardous by different health departments and hence having a generator in an enclosed place is not a good idea. Therefore, if for instance you are running a food truck and want to hook up your kitchen appliances, having an inverted mounted in your truck is a much better idea than having a diesel generator. The lack of noise levels also mean less complaints from neighbors.

Power quality produced: A diesel generator is typically connected to the load without any power electronic processing unit in between. Hence due to fluctuations in the speed of the engine, the power frequency generated flickers as well. The power produced from a generator, hence, is not ‘clean’. This might adversely affect many modern appliances which are sensitive to power spikes and dips. An inverter, on the other hand, has inbuilt capacitors that smoothen the produced AC output. The power quality is very clean. True sine wave inverters produce perfectly sinusoidal waveforms that ensure your electric appliances last long. Modified sine wave inverters are better suited for light duty applications like charging cell phones.

Power inverter or Generator?

Conventional generators are definitely less expensive than power inverters. However, inverters offer a compact, lightweight and less polluting alternative source of portable power. While generators still find application in particular cases, inverters are becoming increasingly popular due to their simplicity of operation, portability and convenience of use. If you want to decide whether you want to opt for an inverter or a generator, you first have to determine your particular power needs.

If you want to run heavy loads for extended periods of time quite regularly, then choosing a generator is justified (For instance, if due to certain power outages you want a backup supply for your workshop or business establishment).

However, inverters prove to be really helpful in more common cases like supplying backup power to homes, portable power during hiking or camping trips and mobile vehicles like RVs, food trucks and boats. Cases where noise levels or exhaust fumes are of concern (for example, in an enclosed space like the kitchen of a food truck), inverters are better options than conventional diesel generators.

Where to use a generator?

A commercial diesel generator is useful in scenarios where you have to run heavy loads for a long period of time. Here are some cases where it is justified to opt for a generator over an inverter.

i) Electricity supply is shut off at your business establishment for routine maintenance, but you need to keep the business open and run some equipment.

ii) Electricity outage at home for days and you need emergency backup.

iii) Outdoor events like a wedding or a reception party at a remote location without reliable AC supply that needs to use heavy equipment like musical instruments, stereo, speakers etc.

Where to use a inverter?

At other situations where you would need a portable clean power supply for reasonable loads for a reasonable amount of time, inverters are great convenient and environment-friendly options. Here are a few cases where power inverters are preferred.

i) On a fishing trip when you need power supply on your boat to charge your phone, camera and GPS.

ii) When you are hitting the road on a RV and want to keep your coffee makers, microwaves, radio, televisions and toasters running.

iii) In mobile kitchens and enclosed spaces where fume exhausts from generators would be a concern.

With this we conclude a detailed discussion on the several differences and uses of generators and inverters. We hope that you will be able to make an informed decision about the device you need once you have determined the power you need according to your unique user situation.