A key player in the operation of an RV’s electrical system is the RV inverter. RV inverters provide the appropriate type of power to appliances in modern campers that require AC power.
But not all inverters are created equal! In fact, there are three main types of inverters on the market that can be found in RVs, each type having a different set of capabilities and limitations.
RV Inverters
An RV inverter has a fairly straightforward responsibility in a camper. Its primary function is to convert direct current (DC) power into alternating current (AC) power and send that power to a breaker box which, in turn, distributes the power to the various AC appliances.
It is necessary for campers to have inverters because RV batteries only store 12-volt DC power. Without an inverter, a camper wouldn’t have an ability to utilize that 12-volt DC power in powering its 120-volt AC appliances. While this may be fine for small campers with limited power needs, most RVs have multiple circuits needing 120V AC power, first and foremost being wall outlets.
How Does an RV Inverter Work?
The power being supplied to an inverter is direct current. As DC power flows, it sits at its maximum voltage and continues flowing without any fluctuations in that voltage. It is called “direct current” because of this constant, predictable, direct flow pattern.
Alternating current on the other hand, fluctuates between its two peak voltages very rapidly. So, if a circuit is running 120-volt AC power, the power in that circuit will be rapidly alternating between 120V and -120V. This creates a wave-like pattern when the flow of energy is tracked on a graph with voltage on the Y-axis and time on the X-axis.
In order to supply 120-volt power, an inverter is essentially manipulating direct current power to mimic the shape and flow of alternating current power. This is done by forcing the direction of the DC input to switch back and forth rapidly. This rapid and sustained changing of direction simulates the shape of an AC power output and allows AC devices to utilize that power as an energy source.
Unfortunately this process is not without flaws. Very basic inverters are not able to perfectly simulate the shape and flow of alternating current power. The rapid change in direction caused by the inverter results in a square shaped flow, which can be damaging to electrical equipment that is designed to operate using smooth shaped power.
Several types of inverters ranging in capability and price have been invented to overcome this hurdle. In the remainder of this article I am going to briefly discuss three types of inverters: square wave inverters, modified sine wave inverters, and pure sine wave inverters.
Square Wave Inverter
Square wave inverters are the absolute bottom of the barrel in the inverter world. They produce an alternating current with abrupt, sharp corners that is less than ideal for most electronic devices to use. With electronics becoming more technologically advanced daily, square wave inverters are rapidly becoming impractical for running anything other than tools with universal motors.
Pros
- Incredibly cheap
- Low maintenance and repair costs due to simple design
Cons
- Not compatible with many modern electronics
- Significant reduction in energy efficiency
- Produce loud noise when in use
I do not suggest installing a square wave inverter in an RV that will be used for traveling and adventure purposes. Some very old RVs might have a square wave inverter installed from their original manufacturing. If you buy a vintage, fixer-upper RV, it will almost certainly be necessary to upgrade to a modern sine wave inverter for your electrical system.
Modified Sine Wave Inverter
A modified sine wave inverter lies in the middle of the playing field in terms of function and cost. Modified sine wave inverters produce a flow of energy with a similar shape to a square wave inverter but with a slight difference. In modified sine wave inverters, the AC output has an additional step in between the peak voltages. In a sense, this “softens” the edges of the current, making it possible for more devices to utilize the AC power they produce.
While a modified sine wave inverter will work with most electronic devices, a large majority of these devices will experience a reduction in energy efficiency.
Pros
- Exceptionally affordable
- Compatible with most electronic equipment
- Readily available at RV supply retailers
Cons
- Reduces energy efficiency of electronic devices
- Sensitive electronics are susceptible to damage from AC output
- Can result in a humming noise in speakers and flickering in lights
If you buy an RV off the lot or used from a private seller, it might come with a modified sine wave inverter. Depending upon your power needs, this RV inverter may or may not be suitable for your travel lifestyle. If you end up in this situation, it’s very important to give some serious thought to your power consumption and use in your RV.
I wouldn’t hesitate to upgrade your RV inverter if necessary, even if it is a hefty financial investment. Better to dish out some cash on the front-end to avoid facing substantial costs in repairing or replacing damaged electronics.
Pure Sine Wave Inverter
Pure sine wave inverters are top-of-the-line. These inverters produce AC power that perfectly mimics the power that is supplied to a house from utility companies, AKA “the grid”. This is very important because almost all AC devices are designed for optimal performance using grid-supplied power.
Microwaves, light dimmers, and some types of motors will only operate using pure sine wave power. The TV in this travel trailer by adventure camper manufacturer, Ecocampor, will display a clearer image when using pure sine wave energy.
If your RV has any of these appliances, it will probably need a pure sine wave inverter to provide AC power for its electrical system.
Pros
- Compatible with all AC devices
- Optimal power efficiency
- Reliable and high-performing
Cons
- Expensive
- High-skilled RV technician or electrician needed for diagnostics and repairs
Any person building or renovating their own RV shouldn’t consider purchasing any other type of RV inverter. The advantages significantly outweigh the drawbacks.
Some advanced models of pure sine wave inverters are manufactured with an integrated converter. When a camper is plugged into shore power, the RV converter, also known as the “battery charger”, converts that AC power into DC power for storage in the battery bank. Without a converter, there would be no ability to store shore power for later use.
Combining the inverter and converter into one piece of equipment guarantees the two components will play together nicely and increases the chances of building a smooth, seamless electrical system.
Frequently Asked Questions
How do I know if my RV inverter is working?
You will know if your RV inverter is working if your batteries hold a consistent charge between 12.3 and 13.1 volts. Test your battery voltage using a digital multimeter.
How do I power my rig using an inverter?
Inverters do not power a rig. They simply convert the power being supplied from your batteries to the appropriate voltage and current type. Charge RV batteries using shore power or solar panels.
Whew! That’s a lot of information about inverters. In the real world, it is unlikely you will interact directly with your inverter very often. RV inverters tend to live a quiet life, silently toiling away to provide your rig with AC power.
Should you ever need to replace your inverter? treat yourself and your rig right and buy a nice, multi-featured pure sine wave model.
Happy camping!
