The Difference Between a Low Cost Power Inverter and the More Expensive Models

Have you ever wondered why some inverters cost much more than others of the same power. I will briefly describe one of the main differences between a low cost power inverter and a high cost item.

Finding a power inverter to convert DC power to AC may seem like it should be a simple task, but when you start shopping for a power inverter for your personal use, you'll soon find that many choices will confront you. With prices ranging from less than $25 to well over a $1000, it can be difficult to know what features are important and how to choose a unit appropriate to your needs.

While wattage you need and how you will be connecting the unit to your power source are items to be taken into consideration, another item that you should take into account is the inverter's wave form output. There are two general types of power inverters: true-sine wave or modified-sine wave (square wave). True-sine wave inverters produce power that is either identical or sometimes slightly better to power from the public utility power grid system. The power wave when viewed through an oscilloscope is a smooth sine wave. Modified-sine wave and square wave inverters are the most common types of power inverters on the market. Modified-sine wave power inverters produce a power wave that is sufficient for most devices. The power wave is not exactly the same as electricity from the power grid. It has a wave form that appears as a choppy squared-off wave when viewed through an oscilloscope. What does that mean to the everyday user? Not much. Most household electrical devices will run perfectly fine on either type of wave form.

Most of our customers who are using a power inverter to run a laptop, a/c cell phone charger, fan, or camera find that a modified-sine wave power inverter that operates through the cigarette lighter socket the easiest to use.

We usually suggest choosing power inverters that are rated under 300 watts when using the 12-volt cigarette lighter socket found in most vehicles. We suggest this because after reaching 300 watts of draw on the inverter, the fuses in your car will begin to blow. There are several units available on the market powered between 100-200 watts that plug directly into the cigarette lighter of a vehicle. It has only one outlet, but since plugging it into a 12 volt socket is all that is required for operation, it can't be beat for ease of use. These little units usually supply around 150 watts of continuous operation and normally have a built in surge protector.

Square wave units or your low cost power inverters fall into the following three groups:

500w or less For household appliances, TVs (up to 19"), VCR, desktop computers, other mobile office equipment. Most of these connect via a 12-Volt plug.

501-999w For household appliances, large screen TVs, 5-amp power tools, and bread machines. Most such inverters are connected directly to the 12-volt battery and have three or more grounded outlets for powering several products at the same time.

1000-3900w For household appliances, larger power tools, microwave ovens, toasters, and hair dryers. All of theses inverters are designed for direct connection to the battery network and can generally supply 750- 2500 watts of continuous power.

The problem with wave form only comes into play when specialized pieces of equipment need to be powered. Here are a few devices which could have problems when they are connected to an inverter producing a modified-sine wave signal: oxygen concentrators, fax machines, laser printers, high voltage cordless tool chargers, equipment with variable speed motors, electric shavers, and garage door openers. For most all other applications you can go with the low cost power inverter.

In closing, it is really not necessary for the average user to go with the true sine-wave unit. The modified sine-wave found in most low cost power inverters will be sufficient take care of your applications.

For more information on power inverters please visit http://inverterssavegas.com

How Does A Power Inverter Work?

People always ask us "exactly how does a power inverter work?" The answer to this question often surprises our customers. Car power inverters work much more simply than mysteriously, and the learning curve required to understand them requires no more than a very basic knowledge of electricity. Essentially, there are two forms of electrical power in the Universe: Direct Current (DC) and Alternating Current (AC). Direct current flows continuously from the positive electrical pole to the negative electrical pole. Alternating current flows back and forth between the two poles. DC current occurs in Nature and batteries, while AC current is man-made and supplies power through the public utility grid that supports human industry and infrastructure. Car batteries presented a problem in the past when people realized they needed to operate traditionally AC-powered devices in their cars but could not do so because of incompatible current requirements. Manufacturers like Vector stepped up to solve this dilemma by working to design car power inverters that would safely and efficiently convert DC to AC. Their successful engineering has resulted in a wide range of compact, rectangular devices that connect to batteries and output the resulting alternating current safely through one or more standard electrical plugs.

Two factors determine how a power inverter works: wave output and wattage output. Wave output describes the physical appearance of electrical signals as they move across an oscilloscope. Square waves appear exactly as their name specifies: like squares on a grid. Pure sine waves, also called true sine waves, appear as visible waves on the screen. Sine wave car power inverters work better than square wave power inverters when uninterrupted power flow is a critical issue. In fact, true sine output is sometimes slightly superior to that of public utility power grids! Because of this, they are also the most expensive devices of their kind on the market. Recent advances in technology have accommodated users on a budget with a hybrid design generally referred to as either a modified square or modified sine wave power inverter. The technical differences that determine how a true sine car power inverter works and how a modified sine power inverter works are too minor to produce any noticeable effects with standard electronics. Only the most high-end equipment requires true sine output, and the cost of these devices may justify the additional investment in pure sine technology to deliver maximum quality and reliable performance.

Another new development that allows car power inverters to work with even more reliability than ever before is the sophisticated Soft Start Technology, branded "SST" by manufacturers such as Vector. SST is the next step in the evolution of how power inverters work. The very first power inverters for cars would only work intermittently during cold engine starts. Because they could not pull enough power from the battery, they would shut down from current underload and require a manual restart. SST resolves this issue by gradually increasing voltage ramp up during engine startup. If the output dips for any reason, SST makes instant adjustments to compensate and will prevent most shutdowns. If in the rare event a shutdown does occur, the newer car power inverters work automatically to restart themselves without distracting the driver from the road.

Red Hill Supply delivers only the best and most reliable power inverters that will work in virtually any situation requiring DC-AC conversion. Learn more about how power inverters work in our Resources section, and browse our online catalogue to obtain the most high end.

Jason has been in the construction equipment and industrial sales business for over 10 years. He owns and operates Red Hill Supply to better serve the automotive and industrial industries. - Automotive Tools