What Does An Inverter Do In An RV?

What Is An RV Inverter?

The actual inverter technology was invented by Toshiba in 1980. The RV inverter was transposed from the marine industry to the RV industry, as the marine inverters were used on boats first and then further developed into more sophisticated and easier-to-use setups.

An RV inverter takes 12V DC and converts it into 120V AC. Many folks use it to convert battery power to run the microwave, charge their laptop or run a coffee machine when they do not have access to shore power.

RV Inverter Vs. RV Converter

One uses an inverter when you need 120V power from your 12V battery.

On the other hand, one uses a converter when converting 120V to power the 12V appliances, such as lights, slide motors and water pump.

Types Of Inverter Needed On An RV

There are three different types of inverters for an RV: the square wave inverter, the modified sine wave inverter and pure sine wave inverter.

Square Wave Inverter

This one is rarely used anymore, mostly because they are very limited (although the most economical option). A square wave inverter will run simple things like tools with universal motors without a problem, but not much else.

Modified Sine Wave Inverter

“A modified sine wave inverter actually has a waveform more like a square wave, but with an extra step or so. A modified sine wave inverter will work fine with most equipment, although the efficiency or power will be reduced with some. Motors, such as refrigerator motor, pumps, fans etc will use more power from the inverter due to lower efficiency. Most motors will use about 20% more power. This is because a fair percentage of a modified sine wave is higher frequencies – that is, not 60 Hz – so the motors cannot use it. Some fluorescent lights will not operate quite as bright, and some may buzz or make annoying humming noises. Appliances with electronic timers and/or digital clocks will often not operate correctly. Many appliances get their timing from the line power – basically, they take the 60 Hz (cycles per second) and divide it down to 1 per second or whatever is needed.  Because the modified sine wave is noisier and rougher than a pure sine wave, clocks and timers may run faster or not work at all. They also have some parts of the wave that are not 60 Hz, which can make clocks run fast. Items such as bread makers and light dimmers may not work at all – in many cases appliances that use electronic temperature controls will not control. The most common is on such things as variable speed drills will only have two speeds – on and off.”

Pure Sine Wave Inverter

“A sine wave is what you get from your local utility company and (usually) from a generator.  This is because it is generated by rotating AC machinery and sine waves are a natural product of rotating AC machinery. The major advantage of a sine wave inverter is that all of the equipment which is sold on the market is designed for a sine wave. This guarantees that the equipment will work to its full specifications. Some appliances, such as motors and microwave ovens will only produce full output with sine wave power. A few appliances, such as bread makers, light dimmers, and some battery chargers require a sine wave to work at all. Sine wave inverters are always more expensive – from 2 to 3 times as much.” (Source: www.solar-electric.com.)

How To Use An RV Inverter

Once you have an installed inverter, this is how you use it:

Step 1: Plug the inverter into the 12V socket.

Step 2: Turn it on.

Step 3: Plug whatever device you need to power with 120V AC.

Keep your overall power draw in mind to avoid issues.

To test if your inverter is functioning properly, “[c]onnect the inverter to your battery and plug it in a controlled and limited power like a low voltage lamp. Now, use a voltmeter to get the reading of the inverter output and see if it works fine. If everything is okay, the machine should work perfectly, and the lamp should light up as well.” (Source: www.electricaleasy.com.)

To wire your RV inverter, follow these steps:

1. “Identify the fused circuit you wish to use. Note: if the fuse size needed for the inverter is greater than 40A, a regular blade fuse holder will not be large enough. You’ll need to install a larger ANL fuse holder and fuse.
2. Ensure the battery bank is isolated by switching off the input and output cut-off switches.
3. Disconnect from shore power and the generator.
4. Secure the inverter to its operating position.
5. Ground the inverter as per the manufacturer’s instructions.
6. Secure the fuse holder in a location close to the battery or the positive supply busbar
7. Connect one end of a red, positive cable to the ANL fuse holder and the other to the positive side of the battery or busbar terminal. 
8. Connect one end of the negative black cable to the negative side of the inverter and the other to the earth busbar or vehicle’s earth point. Note: use either a ring connector or terminal end crimp depending on the earth busbar or earth point configuration.
9. Connect one end of another red, positive cable to the positive side of the inverter and the other end to the ANL fuse holder output terminal.
10. Confirm all connections are secured and tight.
11. Insert the fuse.
12. Switch on the output battery isolator switch to allow power to flow through the new circuit.
13. Switch the inverter on without connecting any AC appliances.
14. Confirm you have a 12v DC supply to the inverter using a multimeter.
15. If all is good, connect an AC appliance to confirm it is powered as expected.
16. If the multimeter doesn’t indicate a 12v supply, you need to troubleshoot the circuit to identify the problem.”

(Source: https://mowgli-adventures.com/rv-inverter-installation-guide/)

How To Estimate Your RV Power Needs?

If you are RVing off the grid or frequently boondocking, you will want to have an inverter that can help you power your 120V needs continuously. This means you want to make sure you don’t drain your 12V batteries, either.

When you use the inverter with solar, you can easily power your entire RV, but make sure you do the power needs assessment and calculate the amount of solar panels and batteries before you purchase the right-size inverter.

Most inverters run from 1,000-5,000 Watt, with most RVers needing an average of 2,000-3,000 Watt.

“You can easily estimate the size inverter you’ll need by adding up the largest number of watts you’ll be using at a given time and adding 20%. For example, let’s say you need 1,500 watts to run your computer and microwave at the same time. Take 1,500 + 300 (which is 20% of 1,500) = 1,800 watts. This means you’ll need a pretty average size inverter of at least 2,000 watts. A 2000- or 3000-watt unit is the most common size used in RVs.” (Source: battlebornbatteries.com.)

The highest surge item in the RV is the AC unit, with 1,500W at startup and 1,000W draw when running.

How Big Of An Inverter Do You Need For Your RV?

The size of the inverter depends on the application: how much power will you need? How many appliances will you need to power? Will you use solar?

“Depending on size, most RV’s should operate off inverters rated at 2000 to 4000 watts (continuous). Generally, inverters will supply surge loads of 1.5 to 2 times their rated continuous output to allow for high demand start up loads such as fridges and compressors.” (Source: blog.cdnrg.com.)

Make sure you buy scalable for future use and expansion, if you can afford it.

What AC Appliances Can You Run At The Same Time?

Depending on the capacity of your inverter and your ability to generate and store power (think solar), there are some great estimation tools to calculate your overall draw and to figure out what you can use at the same time. Keep in mind that you will have to know the Wattage needs of each electric appliance (this is usually listed on the label of each appliance). There is a startup Wattage and a continuous running Wattage for certain appliances, such as the AC unit or the microwave.

The Website below lists some options of what appliances will run on which size of inverter:  https://walkingsolar.com/what-will-a-500-750-1000-1500-2000-3000-4000-watt-inverter-run/

Here is another Website that has a great calculation chart of what appliances you can run at the same time on which kind of inverter:

https://climatebiz.com/inverter-size-chart/.

How To Choose The Best RV Inverter

Below are some top-pick brands (listed with best choices at the top), along with the pro’s, con’s, or features and their price range:

AIMS 5000 Watt 12 Volt DC Power Inverter

Pro’s:

• Fairly affordable
• Good performance
• LED indicators
• Great fit for charging your electronics

Con’s:

• Remote control
• Noisy

Price range: approx. $460

Krieger 1100 Watt 12V DC Power Inverter

Pro’s:

• Small
• Two USB ports and two outlets
• Remote switch
• LED screen
• Affordable

Con’s:

• Limited performance (not sufficient if you want to charge several appliances)

Price range: approx. $90

Energizer 3000 Watt Power Inverter

Pro’s:

• Heavy-duty
• Great for several appliances, incl. gaming

Con’s:

• None

Price range: approx. $300

Xantrex ProWatt

Features:

• Heavy-duty terminals
• Over-wattage protection
• Overload and over temperature shutdown
• 2-year warranty
• ON/OFF remote switch

Price range: approx. $365

Samlex Solar PST Series Pure Sine Wave Inverter

Features:

• LED indicators
• Detachable cable with clamps
• Heavy-duty
• Temp controlled to avoid overheating

Price range: approx. $670

AIMS Power 1500 Watt Pure Sine Inverter Charger

Features:

• 15 Amp GFCI
• 25W power save mode
• 7 battery type setting per charger
• Battery priority selector

Price range: approx. $650

How Much Does An RV Inverter Cost?

As you can see from some of the options shared above, the inverters cost anywhere from $90-$600+, depending on size, performance, quality and application.

To have an inverter installed will run you anywhere from $150 to $500 in labor, based on location and the scope of work (i.e. are you having a whole solar system installed). If you are getting an entire solar system installed, that will run anywhere from $3,500 to $6,000.

Is An RV Inverter Worth It?

An inverter costs anywhere from $150-300+ without installation. This is a significant investment/upgrade and therefore often not high on the priority list for many weekend RVers UNLESS they off-grid camp most of the time. However, for those who want to use solar on their RV as a source of power, an inverter is a requirement.

Below are some reviews from owners of RVs with an inverter and their experience feedback.

Luke Underwood writes about his experience with the AIMS Power 1500 Watt Inverter:

“Wired this to a 500ah battery bank with a 500 amp fuse in between. This is very important. Hard wired the ac side to a sub panel running my 2 kw well pump, 1 kw microwave, and 1.5 kw vacuum cleaner. Have ran both the microwave and vacuum cleaner (3.5 kw) at the same time with this inverter. They ran smoothly and operated normally. My old well pump drew over 9 kw when first starting and this inverter promises to do that. However, the inverted kept overloading every time the pump kicked on, with no other loads running. I called AIMS and got immediate help. The guy helped me to diagnose the problem which was an insufficient battery bank. If you are counting on the 12 kw surge this inverter promises, I would recommend a minimum 2,000 ah battery bank. This was my one and only setback to this purchase. I saw nowhere in the manual that explained I needed a certain size battery bank.

I also purchased the optional remote control. It is awesome! It gives you a reading of your input and output voltage as well what percent capacity the inverter is outputting. This was one of the reasons I bought this unit. Also very handy is the power saver mode. The unit only draws around 18 watts in this mode and only enters full power when it senses a load present. Be careful though. When in this mode the microwave keeps beeping every three seconds as if it is trying come on. Overcame that by putting in a flick switch at the receptacle and flipping it on before I use the microwave.

All in all, this unit is very well built it seems, very heavy, marine coated to protect from moisture, and looks great. It is much more affordable than most inverters and made in the U.S.A. The usual manual is very thorough and explains virtually everything you need to know it order to operate the unit.” (Source: www.amazon.com)

Another user reviewed the Xantrex 817-2000 Freedom X Inverter, 2000 Watts, 120VAC Output, 12VDC Input: “This is a high power sinewave inverter. Installation is critical and best accomplished by an accomplished electrician using proper gauge wire and electrical connections. I had no difficult connecting 4/0 copper cable between the batteries or 10 gauge stranded THHN conductors run in liquid tight PVC conduit for the AC circuits to use the builtin automatic transfer relay. This inverter provides very clean AC power, much cleaner in both frequency and voltage than my generator. The inverter provides robust programming ability to meet virtually any use that is required of it. It starts and runs my Atwood 13,500 BTU AC or my microwave over in my RV. It will supply more than 2,000 watts, however it does not like doing it too long as it goes into alarm and will not shut down instantly powering though surge demands. The dual fans are quiet in operation. I am very impressed with the efficiency of this inverter, its clean power, and the transfer relay that allows it to operate completely unattended whether on shore, battery or generator power.” (Source: www.amazon.com)

Common RV Inverter Troubleshooting Tips

Some of the most common issues with inverters are:

1. A tripped circuit (fuse)
2. Overheating
3. Battery draw (no “juice” left)

If you get no power from the inverter to your appliances, you likely have an inverter issue, or the battery is dead. To troubleshoot your inverter, check out some of these videos:

https://www.youtube.com/watch?v=apVT38-e0ZY

https://www.youtube.com/watch?v=kzc3-4_rG50&t=193 (start at 3:13)

https://www.youtube.com/watch?v=ZpG33cqoBDc

FAQs

Are inverters easy to install in an RV?

Some people aren’t comfortable installing anything involving electricity, so they prefer the help of an electrician. However, there are several step-by-step DIY videos one can glean from and see if they are comfortable doing the install themselves.

Can you leave an RV inverter on all the time?

For most installations, an RV inverter should be turned off when not in use. This is because an inverter can drain power from batteries even when there is no power being used.

How can you tell if an RV has an inverter?

Very few RVs have an inverter already installed, as this is an upgrade expense for those who want to do offgrid camping a lot. To locate the inverter, look close to your 12V battery. It is likely mounted someplace out of the way. There should be a line going from the inverter into the 12V battery, then going to the breaker and then going to the main panel (after going through the inverter and the auto switch).

Can more than one inverter be used at the same time?

Yes, this install is called string inverter install and refers to parallel inverter install. This is usually to get the most out of your solar panel install.

Can you plug your RV into an inverter?

Yes, especially if you frequently offgrid camp, this is the way to do it. The inverter acts as your generator, so to speak.

Does the inverter charge the battery in an RV?

Only when plugged into shore power, or when converting power from solar or acting as a “generator”. An inverter generally converts 12V into 120V.

Can I drive my RV with the inverter on?

Yes, it’s actually a good idea to do that.