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RV Inverters

Read This Disclaimer First!  I’ve written what I personally did, and my opinions. Don’t assume what I did was safe, and don’t assume it will work for you. Do more research and make your own choices. I’m not responsible for your outcomes! :-)

Here are a few questions to help you get started:

  • How big does the inverter need to be? Up to a point, bigger is sometimes better if you’re installing a single inverter in your RV. You may not want to power the microwave now, but you may decide in the future that you’d really like to heat up your cold cup of coffee, and just 45 seconds would do.
    • The minimum size inverter that will reliably run small microwaves and coffee makers is 1500W.
    • Match the size and type of the inverter to your Battery Bank, and to the appliances or equipment that you will be running
    • An energy audit will tell you what you really need. If you haven’t done one see our page on Determining Your Needs
    • If you only want to run a TV or a laptop you may be able to get by with a much smaller inverter. Some small 400 Watt inverters plug into a cigarette lighter outlet and do a fine job. A good pure-sine inverter of this size will run your TV, DVD and Satellite. Or it will power a laptop and a printer. You could also install a small inverter permanently, say 400 or 500 Watts, to run home entertainment.
  • How will you install it? Some inverters can be hard-wired into your RV electrical system and operate automatically.  Many motor homes come this way.  This is very convenient, but also the more expensive way to go. You can even integrate them with electronic controls to automatically start your generator when the batteries get too low. An alternative is a manual system, where you plug your shore power cable into the inverter. This is how our first RV was wired. Less convenient but frugal.
  • Do you need a battery charger? Many of the larger inverters come with a built in charger. Typically a 2000 Watt or larger inverter will have a 50 to 100 Amp 3 or 4 stage charger. These are much better than the typical RV converter/charger. If you are planning on a more powerful charger anyway, the combo units make sense.
  • Do you need a Pure Sine Wave inverter, or will a Modified Sine Wave do? Here are the basics:
    • A Modified Sine Wave inverter uses less expensive technology so it costs much less to buy than comparable pure-sine units. The output is not a true, smooth, sine-wave but is a stair-stepped square wave. It will run most appliances like TV’s, tools, most microwaves, etc. However, it often makes noise lines in a TV picture, and some AC motors will run hot on a modified sine wave. It will not run most laser printers, and some times electronic displays will not work right.
    • A Pure Sine Wave Inverter produces power that is identical to the electric company (or even better). It will operate sensitive equipment like medical devices, high end stereos, TV’s, laser printers, and so on. Unless you really need to cut corners and save money, I’d recommend a Pure Sine Inverter.
  • Can I Recommended a specific Inverter? Sure, I’ll recommend a few options.
    • Outback is my current favorite for performance and value; although I don’t own one it’s what I plan to buy when my old inverter finally kicks the bucket.  Outback has several models including both vented and sealed units.  It’s the sealed marine inverter that interests me.  My 2001 National Islander has the inverter mounted in a ridiculous location, open to the engine compartment, and the original equipment inverter was literally choked with dust and debris.
    • Xantrex ProSine. The 2000 watt unit has been around for a long time.  It was once considered the standard, but has fallen a notch due to quality issues.  Still a better choice than most.  Also available in 1500, 2500 and 3000 watt models, with a charger built in.  There are also inverter-only models without a charger.  They are available in different configurations so they can be either hard-wired into your electric system or free standing.
    • For the frugal minded, we’ve been satisfied with our Samlex 1500 stand-alone inverter (no charger).  Samlex makes pure-sine inverters at reasonable prices with 150W to 2000W outputs.  We’ve had ours since 2005 and it’s been used extensively for well over 1000 days of dry camping!
    • If you don’t want a pure sine wave inverter (maybe because of cost?) the Freedom 458 is considered a solid choice for a large hard-wired modified sine wave unit. Tens of thousands of new motorhomes have rolled off the line with one installed.
    • I specifically do NOT recommend the AIMS brand inverters. We had one. Bulky, low tech, ours had quality issues and failed quickly.

Here are some links to learn more about Inverters:

12 Volt Side Of Live – Part 2 – Excellent article by Mark Nemeth on Inverters and other topics. This is really everything you need to know :-)

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