Electronic Components in Your RV

flux_capacitor Things have gotten complicated on newer RVs, and you need to keep up with the times. Don't go jabbing at the buttons on your flux capacitor without knowing exactly what you're doing, or you'll be standing there struggling to comprehend the unexpected results with that funny look on your face.  Let's review some of the main components of RVs, new and old, and get a handle on what they do.  OK? And keep your fingers off the buttons until I tell you it's OK, or this blog post could take an unpredictable turn.

Look old? It IS old. the converter is the stuff in the bottom compartment, below the AC breakers (top left) and the DC fuses (top right).

Look old? It IS old. the converter is the stuff in the bottom compartment, below the AC breakers (top left) and the DC fuses (top right).

Let's start with old school – converters. This terribly chosen name is applied to a device in older models of RV which is basically a  battery charger. It takes regular house current electricity, shore power or 110 volt alternating current, and converts (get it?) it to direct current voltages in the 13-14.5 volt range suitable to charge the coach batteries in your RV. This alternating current could come from a campground hook-up or your generator.

Converters are called 2 stage and 3 stage – “stages” in this sense meaning levels of charging voltage for the battery. Three stage converters are easier on your batteries because they have what is called “float” voltage – a lower voltage in the 13.5 -13.8 range (depending on temperature) which maintains charge in fully charged batteries without bubbling off the battery fluid.  If yours ever breaks, replace it with a 3-stage converter.

inverter

This is my inverter/charger – a 3000 watt Xantrex. Like many monsters, it lives under the bed.

By the mid-2000s, Roadtreks were starting to incorporate inverters, which do the opposite of what converters do.  No, they don't make your batteries immortal – they take 12 volt battery current from your coach batteries and change it into 110 volt alternating current. This means that you now have household current in (some of) your wall plugs even when you're not plugged in or running your generator, so TVs and can be regular TVs, not 12 volt TVs.  RVs start to look more like little houses instead of big cars.  There's a limit to how much household current you can draw out of your inverter, and that's usually listed as its capacity in watts.

The first inverters in Roadtreks were 750 watts – enough to run electronics, but not the microwave. Later versions have 1250 watt inverters, which will run the microwave.  The newest designs and retrofitted Roadtreks have HUGE inverters – 3000 watts and larger.  These are necessary to run the high-wattage items like the air conditioner, instant hot water heater, and induction stovetop. Giant inverters need giant battery banks to provide them with enough 12 volt juice to crank out the watts – just buying a big inverter for your 1994 190 Popular won't let you run the A/C at night.

Many inverters are what's called inverter/chargers – they can switch current back and forth between house current and battery voltage, often at large amperage necessary to power the appliances in newer RVs, and also to charge the massive battery banks in new models. This eliminates the need for the old converters, which couldn't keep up with the new battery banks anyway. I took my converter out when I installed my inverter/charger.  Inverter/chargers sometimes come with fancy remote display panels that allow you to see what's going on in the electrical innards of your unit.

DIP-Switch

This is a DIP (dual inline package) switch. If you find them, leave them alone.

So what do you, the average RVer, do with these electronic marvels? Mostly, leave them alone. There's an off-on button on them, maybe a reset button. The owner's manual will tell you when these are to be used.  There are also other controls you may find if you are nosy- these are called DIP switches. PLEASE leave these alone. They control basic set-up parameters like the charging profile, to tailor your inverter/ charger's function to match whether you have wet-cell or AGM batteries.

jimhammill

This is Jim Hammill, president of Roadtrek. Jim is smiling. If you mess with your DIP switches, Jim won't be smiling anymore.  Leave them alone.

DIP switch changes are like genetic mutations – 99% of them are harmful to the organism. They are there for the installation technician to use, not for you to play with. All these devices are marvels of engineering – they'll automatically do exactly the right thing to make sure you get and store all the power you can.  In many respects, they are smarter than you are, just like an automatic transmission can accelerate a car faster than a person operating a manual transmission, and a cruise control will get better mileage than you can.

When I put together my homebrew solar package with an inverter and all this other stuff, I installed all these controls and displays out in the passenger compartment where I could see them. If you ask my wife whether this was a good idea, she will tell you no, because I look at them, play with them, talk about them, and generally aggravate her.

In the interests of esthetics, marital harmony, and vehicle safety, when Roadtrek installs these systems they put the controls where technicians can get to them, but bored retired people who don't exactly know everything about RV design can't. I now see the wisdom of Roadtrek's approach.   These devices can struggle along without my input just fine, and have been for three years now.





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Hmm, I wonder what this switch does…

There are

17 comments

  1. RobinLL

    Thank you for writing an article that is so informative, yet easily understood even by myself, who is quite definitely in the, “If I only need to know where the light switch is, don’t explain anything else,” clan. The history cleared up much of my confusion. Thanks again!

  2. Karsten Askeland

    I now know more than I did before I read your article. Didn’t someone once say that a little knowledge can be dangerous??

    I know … I know … leave the buttons alone!!

    Good read … thanks for sharing.

  3. Jim Diepenbruck

    Another masterpiece Campskunk. I’m going to make a confession…I changed one of the DIP switches on the Trip-Lite installed in my 2008 190P.

    Soon after I bought my RT, I changed the two 12V wet cell house batteries to AGM’s. I was happy as a clam because I didn’t have to worry about smelly vapors or low water levels. In fact, I only opened the battery compartments to keep everything clean and put a little grease on the drawer slides. All was working well then one day I was digging through the Trip-Lite manual and discovered one of the DIP switches has a different setting for wet cell and gel cell batteries. I broke out in a cold sweat thinking I might have ruined $250 worth of new batteries. I flipped the switch to the correct UP position than waited to see if I could see or smell smoke. That was a couple years ago and all is well. Please don’t tell Jim Hammill. 🙂

    • Campskunk
      Author

      scandalous! 😉 no, jim, you will be granted dispensation. this is one of the 1% of times when someone is actually changing a DIP switch for a valid reason, and according to what the manual says. it might make a little bit of difference in battery life, but they won’t explode or anything if you ran them a while with the wrong charging profile. i won’t tell jim hammill.

      edit: i pulled up the tripp-lite manual, and it’s strange they lump AGMs in with gel cells – usually gels and AGMs have a different profile. they do clarify in the manual, though, that it’s either wet cell/vented OR all others, so yours is set the way they want it to be set. the gel cells are the ones which might not like a wet cell charging profile, not so much with the AGMs. my inverter has three separate settings for battery type.

  4. Dorothy White

    I have a question about what you consider adequate battery supply. I have solar panels on top of my RV. I am just trying to get set up to go full time Rving hopefully sometime this fall or next spring at the latest. I am wondering how many batteries you consider an adequate supply. So far I have three and figure at least one more. Considering their weight is a factor in trying to decide what is an adequate supply. My RV is a Class C 30′ Gulfstream a 1994. I am also very predisposed to having battery operated and kerosene lanterns as well as other battery operated objects. (I lived in the woods of AK for several years so was very self sufficient as well as owned several different types of generators which supplied extra power when needed). Thanks for your input and I thoroughly enjoy your articles.

  5. Dorothy White

    Sorry, I just left a comment but forgot to check the notify me by e-mail of follow-up. Please do notify me. THANKS again.

    • Campskunk
      Author

      dorothy, i covered the numbers part of calculating how many batteries you need in an earlier article here: http://roadtreking.com/boondocking-basics-electrical-use-while-unplugged/ with four batteries, i have 2000 or so watt-hours of useable power, which should allow me to run the 200 watts of electronics i seem to have on most of the time for 10 hours after the solar panels quit producing power in the late afternoon. that’s on paper, though – i usually get about 6 hours because of other loads, the loss of efficiency in the inverter, etc. if you’re not running a lot of high-watt stuff, four batteries ought to be plenty. class Cs have dual rear wheels and higher weight ratings than class Bs, but check your weight before you add stuff.