Don is a retired engineer and shares his experiences and knowledge with his readers to help them as technology gets more complicated.
Learn What Converters and Inverters Actually Do for You
A new RV owner may not know what the converter and inverter in their RV actually do. As long as everything in the RV operates for them, they are quite happy to just have fun and never take even a moment to think about how all of the electrical equipment in their RV actually works.
But eventually, when some electrical problem comes up, you'll need to know how everything works if you want to find a solution. And they will find out that their home on wheels has two electrical systems, the 12-volt, and the 110-volt, and that the converter and inverter communicate between the two systems. The converter takes 110-volt AC and converts it to 12-volt DC, and the inverter takes 12-volt DC and converts it to 110-volt AC.
In this two-part article, first I'll describe the converter, which was introduced first as standard equipment on an RV, and then the inverter.
What a Converter Does for You
A converter produces 12-volt energy for the use of your RV's devices that use 12-volt DC current: things like lights, slides, and thermostats.
Here's some ancient history. My first pop-up camper, like all pop-up campers and even travel trailers back then, had a plastic box mounted on the front of the camper frame to carry an automotive battery. I would charge an old automotive battery I had in my garage and then mount it on my pop-up before we left home; it provided us with more than enough power for our short camping vacation.
My little pop-up was a simple one, and the only electrical gear in it was a couple of interior lights that needed 12 volts DC to operate. The outside of the camper also had a cigarette-lighter-type receptacle, near the entrance door. This receptacle gave me access to the battery and I used it to power a couple of exterior lights around my campsite each night.
Eventually, I sold that old pop-up, and over the next ten years, purchased several different used travel trailers, each one a little larger than the other, and each with an automotive battery mounted on the front.
But eventually, I found that the automotive battery on the front of each just would not provide enough power for my week-long camping trips. My solution was to start carrying a battery charger with me when I stayed at campgrounds. Whenever my battery was drained of power, I would just hook up my charger and I had several more days of 12-volt DC power to use.
This solution worked temporarily, but hauling that old, heavy battery charger around when I traveled was inconvenient. The solution to this inconvenience was a new device called a converter.
A Converter Supplies Power to Your DC System
As the number of things that needed 12-volt DC power in campers increased, eventually there was a need for a reliable DC voltage source in campers. So manufacturers started physically installing a special design of battery charger, called a converter, into all of their new RVs, from travel trailers to motorhomes.
The converter in an RV is powered by the camper's 110-volt AC electrical system. It will have a standard AC power cord that can be plugged into a home-type AC receptacle at a campground or a house. Converters come in different capacities for different RVs.
A converter is basically a battery charger. It is specially designed to provide just enough voltage to trickle-charge your coach battery. A converter cannot be used to "fast charge" a dead, discharged battery, but it can keep a functional battery charged even while it is being used by the RV equipment.
Though your coach battery nowadays will typically have enough power to support the 12-volt DC needs in a camper for several days, if you are not connected through your converter to a 110-volt AC power source, your coach battery will eventually discharge and much of your RV electrical equipment will stop operating properly. But if you are connected to a 110-volt AC source through a converter, most 12-volt gear in an RV will keep operating most of the time even when RV owners have ignored their coach battery and let it go bad or have its water evaporate. The 12-volt appliances are operating solely on the converter and no longer on the coach battery.
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What an Inverter Does for You
An inverter is a totally different device from a converter; it provides power to 110-volt AC devices like TVs and computers. Like converters, inverters are now standard devices built into all new RVs.
As camping evolved, more and more campers were manufactured with built-in television receivers, which are 110-volt devices. But they found they couldn't watch their TVs for long periods while traveling, because when a camper is moving, parked in a parking lot, or "boondocking," there is nowhere to plug into a 110-volt AC source like the ones available in RV campgrounds.
An Inverter Power certain 110-Volt Equipment
The device that solved this problem for campers who wanted to watch TV off-grid was the inverter.
Simply put, an inverter can take a standard 12-Volt DC source, such as what is provided by the coach battery, and generate a reasonable copy of a 110-VAC wave shape.
So, having your camper's TV set plugged into a receptacle that is powered by an inverter allows you to use your TV even when on the road.
An RV's inverter is normally a relatively low-power device, often having only a 300- to 500-watt capacity, for several reasons.
Televisions do not draw a lot of current, especially modern digital televisions. An inverter will run your TV for a while, but won't supply large loads or multiple days of use without eventually pulling your coach battery down if it is not kept charged in some way.
Over time the owners of larger RVs wanted to use two or even more TVs in their RV. And RV owners eventually wanted a couple of receptacles in their RV where they could use PCs while traveling.
To meet this need for more power, some RV manufacturers installed higher capacity inverters, but most instead installed multiple coach batteries that were connected to provide even more 12-VDC power to the RV equipment.
How to Diagnose an Inverter Problem in Your RV
Now You Know!
So, as you travel and enjoy your RV, always remember that your coach batteries are the most ancient and fundamental part of your electrical system, and critical to the function of many things in your RV.
And if you do start having electrical problems in your RV, keep in mind that your converter and your inverter are what keep many of these things going properly.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2019 Don Bobbitt