Power inverters are becoming more and more common everyday. Most of us now take our electronic devices on the road with us and the need to have an A/C outlet in our cars has been a problem. From our iPods to our laptops, there are countless toys and work related items that we need and want in our cars. This is where the power inverter can save the day. These unobtrusive metal boxes fit easily into a glove box. They can be taken out, plugged into a cigarette lighter and presto, you have an A/C outlet. Now there are many different sizes and models to choose from and also a lot of confusion. Selecting the right model The first question to answer is what make and model do I need. Well, to be fair not all power inverters are created equal or priced equal for that matter. You can pick up an inexpensive model at your local big box store for under $30. However, don't expect it to last very long. I personally purchased 2 of these cheaper models trying to save a buck and neither one lasted more than 2 months. I suspect it was because the cheap model didn't come with a cooling fan and simply burned up. Based on my past experience, I would recommend a model that has a cooling fan. Power inverters build up heat and need to be cooled in order to function properly. Also, look for a model with metal construction as opposed to a plastic shell. I have dropped mine several times getting out of my car and the heavy duty metal construction has saved my car power inverter on more than one occasion. Another feature that the larger models have is the ability to hook your inverter directly to your car battery with a pair of cables and clamps. This is a nice option if you are camping or have a temporary power failure at the house. You won't have to crank your car and the direct connection is superior to going through the thin cigarette lighter wire. The cigarette also limits the amount of watts you pull. Sizing a power inverter Power inverters come lots of sizes, ranging from small 100 watt inverters that fit directly into a cigarette light all the way to a 3,000 way model with 4 or more A/C outlets. Selecting the right size car power inverter is a relatively simple process. How many and what types of devices will you be running from your inverter? To find out, just look for a sticker or label that specifies how many watts that device will require. Sometimes only amps are given and there is a simple formula to calculate the watts. ( Amps X Volts = Watts). Here is a quick list of common electronic devices and their watts: Laptop computer 300 watts Small desk lamp 20 watts Toaster 1,500 watts Radio 15 watts Television 100 watts Installing your power inverter The smaller 100 watt models are the easiest to install. They simply plug into your 12 volt cigarette lighter plug and some models are totally self contained. This means that the whole unit fits right into the power source. This basically converts your cigarette lighter into a 110 volt A/C plug. Larger inverters are in a metal box with a cooling fan and have a cable with an adapter that plugs into the lighter. These models are generally small enough to be stored in a glove box until needed or can be mounted under the dashboard as well. The biggest models have cables that can be directly connected to your car's electrical system or hooked directly to the battery terminals with some clamps. These large 1,000 to 3,000 watt models are great for emergency power in a blackout or on a camping trip. Armed with this information, you should be able to select the right car power inverter for your needs and never be without 110 volt A/C power again!