Converters, Inverters, & Transfer Switches
How this article is ordered:
- The Basics
- How They Tie Into An RV System
- Inverter Recommendations
- Disclaimers
THE BASICS
Lets get you familiar with what these things are, then we’ll talk about how they tie into a system, and we’ll finish with some recommendations.
VIDEO: Inverters, Converters, & Transfer Switches
If you watched the video then you can probably skip down to recommendations, but if you are more of a reading learner then here you go!
CONVERTER
Converters Step Voltage DOWN ↓
CONVERTER:
INPUT: 120 volt Alternating Current (AC)
OUTPUT: 12
volt Direct Current (DC)
Converters take in a higher voltage and lower that
voltage. Most RVs come with a converter already from the factory that take AC power in
(typically 120v from your shore power or generator) and convert it down to 12v DC power that
your battery needs. In most RV scenarios converters are a battery charger. Honestly, that is the
easiest way to think about it.
Converters come in many input and output voltages and can be used in other ways. For example some take a 24 volt battery bank and convert it down to 12 volts for your 12 volt fuse box (which sends power to the appliances). For the most part, most RVs will have a converter that charges your battery bank when plugged into shore power. Typically converters are rated in the amps they send out, and a good quality converter will have several stages of charging for the batteries. Some converters might even have voltage settings for different battery types.
INVERTER
Inverters Step Voltage UP ↑
INVERTER:
INPUT: 12 volt Direct Current
(DC)
OUTPUT: 120 volt Alternating Current
(AC)
Inverters basically do the opposite of converters. They take in a lower
voltage and invert it to a higher voltage. Most RVs DON’T have an inverter from the factory.
They are becoming more and more common nowadays with the use of residential fridges in RVs.
However, even those typically have a small inverter that only powers the fridge. Just like
converters, inverters come in varying inputs and outputs and are typically rated in watts. They
also come in two types… modified and pure sine.
Modified Sine Wave VS Pure Sine Wave
Most of you probably don’t care about the specifics, but essentially modified sine
inverters make power in a “modified” wave which is fine for many applications, but
NOT for sensitive electronics. If you’re just using it for power tools or something like that
then they are fine, but honestly most of you need to know about them simply to avoid them as
you’ll probably want a pure sine inverter.
Pure sine inverters make
power in a “pure” wave which is better for sensitive electronics. They are basically the better
of the two. Because they are better they do cost a little more. I bring this up because if you
see a great deal on an inverter then you’ll need to double check to insure it is not modified!
Continuous Watts VS Surge (Peak) Watts
Inverters are typically rated in how many watts they can produce. However, there are two numbers typically given, continuous and surge (peak) watts. Continuous watts is the rating for how many watts it can continuously make (aka how many watts it can make all the time). Surge watts also called peak watts is how many watts the inverter can make for a short period of time. Normally, an inverter can surge or peak for about 20-30 seconds. So for example, our AIMS inverter charger makes 2500 watts continuously but and surge (peak) at 7500 watts for 20 seconds. I bring this up because sometimes companies will call something “model 2000” and people buy it as they assume it makes 2000 watts but in reality it makes 1600 watts continuously. Keep that in mind and always look for continuous watts.
Basic Inverter VS Inverter Charger VS Hybrid Inverter
Now that you understand the difference between a converter and an inverter, let’s talk about the options for inverters.
Basic inverters are just that, basic. They invert power from DC to AC and that is about it. Most of them will have two sides: the DC side is where the DC wires connect from the battery to the inverter, and the AC side will have a few 15 amp outlets for you to plug AC appliances into. These are a great cheap option for a basic system. If you choose this type you will have to plug the AC appliances into them, and since inverters typically need to be close to the battery bank this wont be a very convenient option. Some people will mount these basic inverters in a unseen location closer to the batteries, and then they will run a surge protector into a common area they need AC power, say by a desk for a computer for example.
Basic Inverter
Inverter Chargers are essentially a inverter and a converter all in one. When you don’t have shore power they invert your DC battery power into AC power, however, when you do have shore power they act like a converter and use the AC power coming in to charge the battery. Just like a basic inverter they tend to have two sides. One for the DC wires to connect to the battery, and the other side for AC power. Some will have a few outlets to plug things into, but they will usually have the option to hard wire it as well. Most inverter chargers will have a built in transfer switch making things even more convenient. More on that later.
Inverter Charger with Transfer Switch
Hybrid inverters are a smarter version of an inverter charger. Just like an inverter charger they are basically an inverter and converter all in one. Here’s what makes this type of inverter special: When you have shore power and for some reason it just isn’t enough to power everything in your RV, the inverter kicks in to help the shore power. For example, if you are plugged into a 15 amp normal wall outlet while staying at friend or family member’s house, you are limited to just 15 amps unless you have a hybrid inverter. You can set the hybrid inverter to know how much shore power is available. So say it’s hot outside and you’re running the air conditioner which is using just about all that 15 amps from the wall outlet, but you need to microwave some leftovers for lunch… when you turn on the microwave the hybrid inverter will see the need for more power than the 15 amps coming in and it will invert your battery bank power to make more AC power that the microwave needs. Then when the microwave is finished, the hybrid inverter will go right back to charger mode and top the batteries back off. These are an awesome choice, but they also tend to be the most expensive option.
Hybrid Inverter
TRANSFER SWITCH
Transfer switches are basically a switch that controls where power comes in from and/or where that power goes to. They can come in varying types and styles. They also come in manual or automatic. Take a look below and look towards the top right of the picture. You can see the power is “switching” from the inverter to shore power. The main reason you want a transfer switch is so you aren’t back-feeding electricity and causing issues. I personally prefer inverters that already have transfer switches built-in (more on those later). Everyone has a preference so I want you to understand the basics behind them.
Manual Transfer Switch
Automatic Transfer Switch
How They Tie Into AN RV System
Okay, you should now be familiar with the components so let’s tie them into an RV electrical system. Remember this is a basics series so the examples are just to show where the items are. In real life there will be more wires and fuses installed, but of course that depends heavily on what components and system you go with.
If you need to see how the transfer switch is tied in, look at the diagram above under the transfer switch section.
Since most RVs come with a converter built in, the below picture shows where in the system it lives. Some converters are wired into the AC breaker box, however, most are just plugged into a plug that is built into the back of RV AC breaker boxes.
A basic inverter is really just connected to the battery bank, and that is about it. You’ll add these to your existing system and turn them on when you need to plug something into them when you don’t have shore power available.
Inverter chargers and hybrid inverters tie into the RV system in the same way. As you can see below the converter will be removed (we sold ours on ebay) and replaced with an inverter charger or hybrid inverter (whichever you choose). I personally prefer these systems purely because they make all the AC appliances and outlets work in your RV with or without shore power.
Inverter Recommendations
Keep in mind that we purchased and installed our solar with our own money and were not sponsored in any way. Below are some personal recommendations in the order from the what I believe is the best and most convenient, to the less convenient but cheapest.
30 Amp RV
Since 30 amps at 120 volts means a 30 amp RV is basically a 3600 watt system, most 30 amp RVs
only have one air conditioner. I bring that up because most RV air conditioners use around 1500
watts. So 3600 – 1500 = 2,100. What this means is if you purchase a 2000 watt
inverter then you should typically be able to power your entire RV (except for the air
conditioner) when you don’t have shore power. Hence why we follow the weather 
. A 30 amp RV is fed by a single hot wire so it is easier to wire than a 50 amp RV. If I just
lost you then be sure to watch the 30 vs 50 amp RV video under the solar course article, and
look at the schematics there. Yes, you can go with a smaller or larger inverter depending on
your intended use. This is just a great middle ground and will be more than enough for most
people.
50 Amp RV
A 50 amp RV has two main hot wires going into two separate 50 amp main breakers. 50 x 120 = 6000 and there are two mains, so 6000 x 2 = 12,000 watts. That’s a large electrical system! If I just lost you then be sure to watch the 30 vs 50 amp RV video under the solar course article, and look at the schematics there to see the differences. Most people while boondocking won’t have a large enough system to power the air conditioners, and they will more than likely need to turn the fridge and hot water heater on propane. Many larger RVs have an electric fireplace as well. I bring all that up because those items pull a ton of power when in electric mode. For us (when we had our 50 amp travel trailer) I simply powered one leg of the AC breaker box which went to the outlets, microwave, and other items we wanted to use while boondocking. The choice is really yours though. You can either buy an inverter than can power one main (aka one leg), you can buy one that can power both mains, or you can by one inverter for each main. It is really up to you and what your systems goal is. For us 2000 watts was enough in the 50 amp travel trailer we owned. But some people want to power as much as they can. Honestly, you just need to look at your RV breaker box in a 50 amp RV and think to yourself, “What do I really need to run off the inverter while boondocking?” That should help you decide what is best for you.
Hybrid Inverter Charger
Victron Multiplus 2000 & 3000
If money is not an issue then the Victron Multiplus is my first choice for sure. The power assist option it has for when you are driveway surfing is just plain nice. They also have a built-in 50 amp transfer switch which means one less component you have to purchase. The Multiplus comes in a 2000 model (1600 watt continuous) and a 3000 model (2400 watt continuous). When we renovated our Lazy Daze motorhome we decided to build our dream solar system and that included a Multiplus 3000!
As far as remote panels go, you have two options. The cheaper of the the two is a basic switch, and the more expensive GX is nothing short of amazing. Victron has an awesome networking ability which means if you get a Victron Solar Charge Controller, Battery Monitor, Multiplus, & the Color GX then all of the systems will talk to each other and you’ll have a nice read out on a nice color screen that you can adjust. I love that I can customize the system for us with relay controls not to mention as long as my RV has Wifi (we use a hotspot) then I can monitor and adjust my solar system from anywhere with my cell phone or a laptop and internet. The networking alone is why it is my first choice if money is not an issue. Although it is the nicest and most convenient system, it’s also the most costly.
Inverter Chargers
AIMS green 2500w Pure Sine Inverter Charger with 30a Transfer Switch
We had the green model in our second RV, the Itasca Viva and it was a workhorse. The green model was not available during our first solar build with the travel trailer, and is basically the same as the more expensive blue version below. AIMS made the green inverter with less features to make it cheaper, however, it is really only intended for the U.S market. Because it is cheaper, it doesn’t have an automatic generator start, is only for 60hz (what we use in U.S), and consumes slightly more power during idle mode. With that being said it is cheaper and makes 500 more watts. Plus it can use the cheaper “LED” remote panel which is all you honestly need. The blue version can’t use that remote panel.
AIMS blue 2000w Pure Since Inverter Charger with 30a Transfer Switch
We went with this model in our first RV (the travel trailer), and it is a great inverter charger. However, we found we didn’t need the extra options it offered such as the auto generator start. If you purchase the blue inverter you have to buy the “LCD” remote display which is much more expensive than the “LED” one the green model uses. If you want the extra features and don’t want to step up to a hybrid inverter this is a great option for sure.
Basics Inverters
GoWise 1000w Kit
AIMS 1000w & Remote
I personally prefer the hybrid or inverter chargers, however, if you just want an easy system and you are okay with plugging stuff directly into the inverter then a basic inverter isn’t a bad option and it’s the cheapest! If you don’t plan to run anything large (like a microwave or hair dryer) then you might be able to get away with 1000w inverter.
GoWise 2000w Kit
AIMS 2000w & Remote
If 1000w is not going to be enough then why not step it up to a 2000w and you should be more than fine, especially when using just a basic inverter.
Disclaimers
- Although I do try to keep up with the current options, and I will keep updating this page over time, you are responsible for verifying any information as it may change.
- The links to products on Amazon are affiliate links, therefore we will receive money for directing you to Amazon for purchase. You are welcome to use them as a thank you for the free information, but it definitely isn’t required.