Power Inverter FAQ – Let an Expert Answer Your Questions About Inverters

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How does a power inverter work?
A power inverter converts DC power into conventional AC power allowing you to use your favorite devices when an AC outlet is not available. Simply connect an inverter to a battery source, plug your appliance into the inverter and you’re set!

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 estimated watts page to help you find the inverter that is right for you.

How far can I keep my inverter from my batteries?
Keep the cables between your inverter and batteries as short as possible. This will help your batteries perform their best and keep the unit’s signal clean. The cables that come with the inverter are “rated” or good for up to six ft. If you plan on going over six ft., drop down to a larger gauge cable. Please call us if you are still unsure. This is pretty important stuff that should NOT be overlooked. If the cables between your battery and inverter get hot while under heavy load, then you should use heavier cables.

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

How long can I expect my devices to run?
The run time depends solely on the amount and size
(capacity) of your batteries.


  • Total the amps on your batteries and divide by 12.
    Take that number and set it aside, we’ll get back to
    it in a moment.
  • Total the amps on the devices you will use on the
    inverter, add another 1/2 amp for the inverter itself.
  • Take THAT total and divide into the first number you
    came up with.
  • The result will be your runtime in hours. The more
    batteries you put in parallel the longer runtime you
    can expect.

With an inverter installed on a truck, can the engine be idled to maintain a charge on the batteries to offset
the drain by heavy powertool use?

Yes, most of our customers will leave their vehicle running while using their unit. We recommend that only 2500 watt inverters and below be used on your truck or large vehicle. Advise your vehicle’s manufacture or mechanic to make sure your alternator will keep up with the amps being used.

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.

My inverter’s fans won’t come on
Good! On almost all of our inverters over 1000 watts, the fans are connected to a thermal switch which will only allow the fans to come on when they reach a certain temperature. This helps keep your batteries holding their charge longer, and also makes it QUIET! Hooray!

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.

What type of batteries do you recommend?
Most of our customers prefer to use deep cycle marine batteries with their inverters. A few advantages are:

  • Delivers higher peak amps faster than conventional batteries
  • Provides up to twice the life of conventional batteries
  • More consistent voltage across the discharge curve
  • Superior cold and hot weather performance vs. conventional batteries

We suggest LiFePO4 deep cycle batteries, as they work extremely well with power inverters. Contact our sales team to find out which one is right for you!

Connecting Batteries Together in Parallel



Suggestions for connecting batteries in parallel

  • Use batteries of identical make, model, and age.
  • Make sure cable gauge is sufficient to handle the higher current flow.
  • Prevent cables from shorting (do not allow them to rub against the vehicle body).
  • Use only high quality connectors, clean all contacts prior to installation.
  • Periodically check all connections for snugness.

Battery installation tips

  • Ensure that the battery is properly secured in the vehicle or equipment to prevent movement or vibration wear.
  • Do not over tighten the hold down bracket
  • Connect high amperage accessories such as a winch to the top terminals only. Do NOT use the side terminals.
  • Replace any cables and connectors that have corrosion, rust, or other damage.
  • Do not install batteries in a non-ventilated or sealed compartment.
  • Do not lift or handle the batteries by the terminals.
  • Do not over tighten terminal bolts

What is the difference between a modified sine and pure sine wave inverter?
Modified sine wave power inverters are more portable than pure sine wave power inverters, lighter, and lower in cost. If your device will handle voltage fluctuations, a modified sine wave inverter should be considered.Most devices that people typically wish to power will work fine with a modified sine wave inverter, as a precaution, please contact the manufacturer of your device to determine if it is compatible.

Pure sine wave power inverters allow motors to run cooler, last longer and provide very clean power like you would receive from a power company. Devices such as laser printers, digital clocks, and most medical
equipment require a pure sine wave inverter to run correctly. As noted above, as a precaution, please contact the manufacturer of your device to determine if pure sine wave power is required.

Here is a video to help explain the difference from our good friends at Go Power! By Carmanah:

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. Need a transfer switch? CLICK HERE!

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.

We like to go camping and travel quite frequently. My spouse uses a CPAP machine, will your models work?
Yes, many of our customers use their inverter for that very reason. We do recommend a pure sine wave inverter though, but as always, please check your manual or contact the manufacture of your device. CPAPs that use a humidifier should always use a pure sine wave inverter.

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 Inverters R Us, we will walk you all the way through the installation process and make sure you’re up and running!

Do you still have a question?
Please feel free to contact a customer service representative by calling 866-419-2616 or email us!