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Some Other Questions You May Have

Why is my volt meter showing me low/high voltage?

Make sure your volt meter is a true RMS reader, if it is not, the voltage rating will most likely be off when testing the voltage output on any type of Power Inverter

Why do I need such humongous cables to the battery when a small cord takes the AC output fine?

Power is volts times amps (Watts = V x A). So if you have a lot of voltage you don't need many amps to get a watt. Roughly you need 12 times as much current from the 12 volt battery as you need from the 110 volt AC outlet. Current is what causes cables to heat up, not voltage. That is why they use thousands of volts in long distance power transmission grids. The thing to do when you have lots of current is to lower the resistance of the cable. The larger the wire the lower the resistance. Think of the cable as a water pipe. A big pipe (wire) can carry more water (current or amperage) with less pressure (voltage), and will present less pressure (voltage) drop from one end of the pipe to the other.Another consideration is how far the cable has to run from the battery to the inverter. Long cable runs are expensive, either in copper or efficiency, or both.

Why don't I measure rated voltages when using a multimeter on my modified sine wave inverter?

The rated voltage is an RMS (root mean square--they square the value to make sure it is always positive, then average it, then take the square root of the average to make up for having squared it in the first place) measurement. Most multimeters are designed to give correct RMS readings when applied to sine waves, but not when they are applied to other waveforms. They will read from 2% to 20% low in voltage. Look for a voltmeter that brags about "True RMS" readings, and that will read correctly no matter what the wave shape is. 

What is meant by the terms "continuous wattage" and "peak surge wattage" on the inverters?

The "continuous wattage" is the wattage that the inverter can supply 24/7 as long as the DC input power supply is in good condition (usually, the DC power supply is a car battery). The "peak surge wattage" is the maximum wattage that the inverter can supply for very short period of time (a split of a second)


NOTE: Induction motors such as air conditioners, refrigerators, freezers, microwave ovens, and pumps may have a start up surge of 3 to 7 times the continuous rating. Heat generating appliances such as hair dryers and water heaters will have high peak surges as well.


Example: If the microwave oven has peak surge which is 4 times the continuous wattage, the 1200 Watt continuous microwave ovens will have 4 x 1200 Watts = 4800 Watts peak surge. The recommended inverter to run 1200 Watt continuous and 4800 Watt peak surge microwave is 2500/5000 Watt inverter or larger. In general, induction motors require an initial surge of power to start up ("starting load" or "peak load"). Once started, the tool or appliance requires less power to continue to operate ("continuous load").

How is an inverter different than a UPS?

A UPS typically includes the battery and battery charger in one standalone unit. A UPS system also can have communication with the equipment that it is powering, letting the equipment know that it is operating on standby, giving it shutdown warning or communicating with the human in the loop. Inverters typically don't have this capability

What's the difference between an inverter and inverter/charger?

An inverter simply converts DC (battery) power into AC power and then passes it along to connected equipment. An inverter/charger does the same thing, except that it is connected to an AC power source to continuously charge the attached batteries when AC utility power is available. In the case of a power outage, the inverter will automatically switch to battery power to provide power to connected equipment.

How do I know which one to buy?

Different devices require specific wattages to run correctly and efficiently. Please use this easy formula to determine the correct 

size model: 

AMPS x 120 = Watts 

Example: 15 Amp Cooling Unit X 120 = 1800 Watts 


Please refer to our "Select An Inverter" page to help you find the inverter that is right for you.

Can I use an extension cord with my inverter?

Yes, no problem. If cables need to be run, it is best to keep the unit as close as possible to the batteries. Use extension cords on the output side (Vac output) rather than extending the VDC cables.


Tip: Contractors often need to mount the inverter in the back of their trucks. In a case like this it would be best to mount a secondary battery near the inverter and wire it to the primary truck battery. Vac extension cords should not exceed 200 feet or you will have signal loss .

What is the Low Voltage Alarm & Shutdown?

The low voltage alarm will sound when the DC source falls below 10 volts and the automatic shutdown will power off the inverter. This is done to save your battery(ies) so you can restart your vehicle.

Is my inverter weatherproof?

No. Treat your inverter like you would your TV. You wouldn’t put your TV outside in the rain, please don’t leave your inverter there either. Be aware of lighting storms. If struck, your inverter would go into a permanent overload state and may even smoke it. If using in a marine environment, try to keep it tucked away underneath, in a dryer area.

Do I need a transfer switch?

Maybe. Never leave an inverter connected to a line where other power (shore, household .etc Vac) may feed into inverter. It doesn't matter if inverter is on or off, you will most likely smoke your inverter.

What’s this hertz thing all about?

Here in the US, things run at 60Hz, in Europe and most other places around the world, things run at 50Hz. You'll most likely require a 60Hz inverter if you are running a device intended to run on US power.

OK, I received my inverter, now what?

Every inverter comes with a helpful manual, but questions may still arise. When you purchase an inverter from Pooxtra, we will walk you all the way through the installation process and make sure you're up and running!