Running a Microwave on an Inverter

My husband, Dave, does not cook.  Well, I should say that he doesn’t cook anything other than microwave popcorn.  But he’s a expert at that!

Dave is also the type of guy who is always hungry, snacks like crazy and never gains an ounce.  Yes, he drives me nuts.

Aboard Que Tal, Dave would make a bag of microwave popcorn 4 or 5 times a week.  We had a huge array of solar panels and with the desert conditions of the Sea of Cortez (very few clouds), we had plenty of power for him to run the microwave off the inverter (if you’re not familiar with inverters — I sure wasn’t before living aboard — be sure to read Inverters 101).

During the winter, however, we’d often spend some time at a marina with shore power — and he’d continue with his habit of popcorn in the afternoon.

With one exception.  He’d always burn the first bag he’d make when we were back on shore power, despite setting it for the same amount of time and using the same size and brand of popcorn bags.

And so, as he made some popcorn this afternoon, he said I should write an article about this.  Okay, honey — here’s your article!

Basically, when you run anything off an inverter, it doesn’t have as much power just due to inefficiencies in the system.  With our microwave, it took about 25% longer to cook anything than when it wasn’t on the inverter (i.e., on shore power or generator).  And Dave would inevitably forget and set the microwave time the same for the first bag at the dock . . . and then we’d suddenly smell the burning popcorn.  And when we left the dock again, he’d do the opposite — set it for the “shore” amount of time — and it would only be partially popped.

So, if you have a microwave on board and use it both from the inverter and from shore/generator power (as opposed to just storing electronics in it during thunderstorms), remember to adjust the time!  Depending on your microwave and inverter, it may be more or less than the 25% difference that ours was, but in talking with other cruisers it seems that everyone did notice a difference.

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  • Norm Pettett
    Posted at 21 December 2012 Reply

    I’ve noticed the low current through an inverter on my BIG truck also, but on the bright side have never had any damage to equipment caused by it.
    I have a 300 watt inverter plugged into a cigarette lighter for my TV and laptop and haven’t had any equipment damage.

  • The Sea and Sailors
    Posted at 06 July 2014 Reply

    Microwave is not good for health!…

  • LaMarr Harding
    Posted at 17 October 2015 Reply

    I have a wave box 12 volt microwave, on Anderson power pole connections.

    Where the microwave isn’t on for a great time. Especially when I buy 5-7 days worth of frozen egg patties, sausage, brats, and burritos. Put the provisions in the refrigerator to thaw out, it doesn’t take as much time to heat them

    Quick and easy for one or two people.

  • Beth Coates
    Posted at 26 February 2017 Reply

    Thank you, very informative 🙂

  • Tim Goodyear
    Posted at 02 March 2017 Reply

    Are you running a pure sine wave or modified sine wave Inverter?

    • The Boat Galley
      Posted at 02 March 2017 Reply

      We’ve had both. Greatly prefer pure sine.

    • Tim Goodyear
      Posted at 02 March 2017 Reply

      Does it make much difference to the inefficiency? I would have thought Pure sine wave (if it can achieve 120V ) would be similar to shore power

    • Tim Goodyear
      Posted at 02 March 2017 Reply

      And BTW, thank you for all the info; I do appreciate your posts!

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