What is a power inverter and why do I want one?

What a “power inverter” does:

Very simply, a power inverter is an electronic device that converts your typical DC current from a car cigarette lighter socket into AC power providing at least one 3 prong electric outlet like you have in your home. This allows you to use your standard plug for small electronic devices while you are in your car. Higher end power inverters allow you to power larger devices and in some cases major appliances.  Most vehicles use a 12 volt battery but there are exceptions so you will need to know what type of battery is in your vehicle when selecting a power inverter.  Most power inverters have an input voltage requirement of either 12 or 24 volts.

See our review of the CyberPower CPS150BU! Click here!

What can a power inverter do for me?

For most people the best reason for owning your own power inverter is to run portable electronic devices that you already own which don’t include a cigarette lighter power adapter. It comes in particularly handy on those long road trips where the passenger wishes to use their lap top for an extended period of time. The power inverter will allow your passenger to plug it in without the worry of running down the lap top’s battery.  Other uses include running MP3 players, video game consoles, and even curling irons.

Power inverters are typically built in to larger recreational vehicles to to charge microwave ovens, refrigerators, tvs, and any number of small appliances.

What are the differences between power inverters and how do I determine what I need?

Power inverters typically come with either 12 or 24 volt input requirements and produce various wattage and sine wave outputs. Lets give a real world example of determining what type of power inverter we need.

  1. Input Voltage (ie standard  12 volt car battery)
  2. Output Wattage. Add up the wattage requirements of devices that may be running at one time. In this example we have a laptop that needs 60-90 Watts and a portable DVD player that needs 90 watts (in an RV we could need substantially more for a wider variety of devices including small kitchen appliances and light bulbs). Some devices may use more wattage at various times such as a lap top’s DVD drive while watching a move.  We’ll use the high end of what is listed on the Lap Top label.  If the device has a much larger maximum/peak wattage requirement it should be listed on the device.We only need a total of 210 watts at peak usage for our example but will add 90 for a second lap top. 300 watt peak minimum
  3. In the case of most small electronics you usually won’t have to be concerned with the expense of clean “sine wave” output filtering which reduces inherent radio frequencies produced by power inverters.  This filtering can more than triple the purchase price and are usually only found in higher end power inverters.  You should be able to determine from your device label if there are any of these sine wave requirements.  Our goal here is to give you the basic information you need to know when selecting a power inverter but there are numerous articles available on the web about RF interference and devices sensitive to radio frequencies for those people interested in knowing more [ listing here ].


Our example shows fairly standard traveler usage but we should note that wattage over 400 should not be run through a cigarette lighter and you will find that inverters rated higher than 400 watts will require cables to connect directly to the car battery (check to see if  cables are not always included). Power inverters create a lot of heat and use various heat dissipation methods to control it. Some customer reviews note that they weren’t expecting the sound levels produced by their power inverter’s fan but in most cases inverters for automotive use are designed to be minimally distracting.

How much do power inverters cost?

We break power inverter pricing into 4 groups as follows:

  1. Under $20 – These units are typically small, lightweight, and are rated under 100 watts. They typically come with one 3 prong outlet and should be considered to be intended for 1 low power device at a time. Because of their low wattage they do not contain very sophisticated cooling features.
  2. $20 – $100 – These power inverters vary in features from 1-3 outlets with operating wattage from 100 to 300 and peak wattage 400 or less. We recommend mid-range inverters in this group for the average driver and that you get the maximum rating and features for your budget because you will appreciate having the ability for more electronic devices rather than to wishing you had it.
  3. $100 – $1000 – Power inverters in this range are usually rated for needs over 400 watts. They are wired directly to the battery with clips or post fittings and are great for Larger vehicles such as vans or SUVs where extended trips and more power users are expected. If you are someone who is on the road for extended trips (truck drivers, long distance sales) you will probably be happier stepping up into this range of power inverters.
  4. $1000+ – At this level we see more full work-horse power inverters including the sine-wave filtered units that create less RF frequency disturbance for sensitive devices such as older TVs or scientific equipment.

These ranges are approximations and you will find much cross over depending on features and profit margins.

Miscellaneous power inverter notes and experiences

The heavy duty power inverters are often used in place of generators in power outtages. As we mentioned earlier, power inverters that connect directly to the battery do not always come with cables so if you are thinking about one of these be sure it comes with cables or be aware that you may need to purchase them seperately.  It is common for customers to receive their power inverter only to find that they have to experience the delay of going back to order cables.

Another example of operating and peak wattage specifications: a small microwave oven in your RV or semi trailer cab may pull 700 watts while in use and peak with 1400 watts while your mini refrigerator may only peak at 150 watts and 90 watts under continual operation.  Add them together and you need an inverter that handles 800 watts and 1600 watts at peak.  A sump pump may pull 2000 Watts on start up and only 750 while running continuously.  The point here is to re-emphisize that you need to consider the usage before deciding which power inverter is right for you while also considering the additional features such as gauges and alarms, particularly if you are planning on high end loads.

CarPartsMall selected Power Inverters

Our product listings have been selected based on value and customer feed back. We only list inverters that have an overall good rating and customer satisfaction.

See our power inverter selections at “http://www.carpartsmall.com/power-inverters/“.



CyberPower CPS150BU Review

Power Inverter Catalog Listing