A power inverter converts DC power or direct current to standard AC power or alternating current, which allows you to run electrical equipment off your batteries for mobile applications, emergencies or simple convenience. They are simple to use and are a quiet alternative to starting a generator to run electrical equipment. There are many styles of Power inverters, they can plug directly into a cigarette lighter or a 12v socket. They might also come with jumperlike cables for connecting directly to a battery. Larger inverters can be hard wired into the bank of house batteries for the motorhome. Larger inverters can also be combination battery chargers as well. Your laptop, phone charger, television, video game player or portable DVD players are all examples of devices which an inverter will operate to get you through a long drive, assuming you’re not the one driving! Power inverters are great for camp sites without electricity. The toaster, blender, and bread maker can all still be used. You can plug in the digital movie camera to capture those great moments around the camp fire that you might have missed after the camera’s battery ran low!
Power inverters come in many models that vary in watts. The amount of wattage you will require on an inverter depends on the total draw of the devices you’d like to use. If you have a two-outlet inverter and will be plugging in 2 devices at once, add up the total wattage of both devices then add at least 50% more to account for peaks or spikes in the power draw. For example if your DVD theatre draws 100 watts and your laptop another 100 watts, a minimum 300-watt inverter is recommended. When using your power inverter continuously inside a vehicle that is not running, the engine should be started at least once an hour for 10-15 minutes to keep the batteries from discharging. Power inverters operate on the assumption that the battery is in good condition and fully charged. A weak battery will be drained easily if demands are too high. Using portable inverters from a cigarette lighter could leave you stranded so be sure to check the battery’scondition before using a power inverter in a stationary vehicle. If the power inverter is being used while the vehicle is running as in the case of a road trip, there should be no problem with the extra draw providing the battery is in good condition.
Power inverters produce one of three different types of wave output:
• Square Wave
• Modified Square Wave (Modified Sine Wave)
• Pure Sine Wave (True Sine Wave)
The three different wave signals represent three different qualities of power output and consequently, three different price categories.
Square wave
inverters result in uneven power delivery that is not efficient for running most devices. Square wave inverters were the first types of inverters made and are obsolete.
Modified square wave
(modified sine wave) inverters deliver power that is consistent and efficient enough to run most devices fine however the squarish waveshape can also confuse the timing circuits in some appliances that use the Mains Frequency to control a clock. This type of inverter is probably the most popular.
Pure sine wave
inverters are more expensive, but they also deliver the most consistent wave output. Some sensitive equipment requires a sine wave, like certain medical equipment and variable speed or rechargeable tools. The following points are a guide – there is a lot of variation in startup surge load and continuous load for similar appliances between makes/models.
Size of Inverter Required Type of Appliance, most appliances have their power rating stated underneath its base.
• 150 watts – Charger for cameras, laptops, and small power tools; DVD player; coffee grinder; kitchen mixer; printer; very small television (non LCD TVs have degaussing coils which can draw 500 watts on startup)
• 250 watts – Small TV, slow cooker, desktop computer, electric blanket
• 500 watts – Small fridge, freezer, small angle grinder, drill, large TV, washing machine (without heat)
• 1000 watts – Breadmaker, microwave (600 watts – keep in mind that the input power for a microwave oven is around twice its specified cooking power level, due to inefficiencies in converting to the very high frequencies needed for cooking – 2 thousand million hertz!)
• 1500 watts – Toaster, small airconditioner, chainsaw, vacuum cleaner, iron
• 2000 watts – Microwave (1200 watts), hair dryer, fan heater, iron
• 3000 watts – Large airconditioner
If you aren’t sure if the device you want to use requires a pure sine wave or not, call the manufacturer to ask. Or if you don’t mind the price difference any device will run on a pure sine wave, whether it requires it or not. The only drawback would be in spending more than you need to for your power inverter. Always use a power inverter that is rated high enough for the device(s) you are running and avoid adapters that would allow more outlets than the unit is designed to accommodate.