How to Add a Microwave to Your Van

My new (used)  microwave.

My new (used) microwave.

When you move into your van to live in it full-time, you give up a lot of things that you had always taken for granted.

  • Light at the flip of a switch.
  • Human waste going down the drain.
  • Heat or Air Conditioning at the turn of a thermostat.
  • Instant hot water to wash your hands or take a shower.
  • A microwave oven.
  • Lots of room to collect more crap!
  • Cable Television

Fortunately, there’s a way to solve most of those problems even if it is much less convenient than in a house. And if I can’t find a solution, well, I just consider the mild discomfort from losing it as a minor sacrifice for the far better life I’ve found as a vandweller.

Of those above, however, one thing I really do miss from living in a house is not having a microwave. I’m aware it’s a pure luxury, but boy is it a nice one to have! You’ve got to understand, I moved into a van to be happier, not to prove a point of how uncomfortable I can make my life. I’m more than willing to do without the things I don’t value, but not the things I really enjoy. So I have Direct Satellite TV and now I have a microwave; they make my life easier and  happier!

For a compact microwave it still has a lot of room inside. That's because of the rounded back corners.

For a compact microwave it still has a lot of room inside. That’s because of the rounded back corners. Over 90% of the things I cook go on a plate or a bowl and they fit perfectly on the carousel.

I’ve wanted to have one for a long time and a few years back I tried using one, but it worked badly. I didn’t really have enough solar panels or enough batteries, but the biggest problem was that I was using a cheap Modified Sine Wave (MSW) inverter. It turns out that microwaves are very fussy about the quality of power you feed them and it would barely work on the poor power from my cheap 2000 watt inverter. It did run and heated food a little bit, but it did such a bad job I soon gave it away.

Since then I’ve been steadily upgrading my system to make a microwave work. I found a good quality 2000 watt inverter that was a Pure Sine Wave (PSW) at Amazon and ordered it about 2 years ago and it has worked flawlessly for me ever since. It was surprisingly affordable for a good brand name. You can currently buy it from Amazon for $375 here: Xantrex PROWatt 2000 PSW Inverter,
Last year I found a great deal on a 240 watt solar panel and went ahead and picked it up with a separate controller and a pair of golf cart batteries.  That brings my total to 570 watts and six, 6-volt golf cart batteries. That’s more than enough to run a microwave and my satellite TV.

All I was missing was the microwave!

One of the main problems with having a microwave is—where do I put it? Most of us just don’t have enough room to give up that much space. But because I tow a converted cargo trailer with an extended van I have much more room than the average vandweller and, I had built the trailer with a microwave in mind. But it still needed to be as small as possible because I didn’t have that much room. So I’ve been searching for a small, compact one for a while and I finally found the one I thought would work for me. It’s a compact 700 watt cooking power micro made my Whirlpool.

What makes it truly distinctive is that it has rounded back corners so it can tuck back into a corner and use the minimum amount of shelf space. It got great reviews on Amazon and as soon as I saw it I knew it was the one I wanted. The only problem with it was that it cost $150.  You can pick up a cheap microwave for $50 or less at Walmart so that made it a lot more expensive than normal. I just wasn’t willing to spend that much money. You can buy it from Amazon here: Whirlpool Compact Microwave

Looking down from the top you can see it is very curved. That allows it to tuck back into a corner. That way it has all the room inside I need, but takes up less space on my counter.

Looking down from the top you can see the back is very curved. That allows it to tuck back into a corner. That way it has all the room inside I need, but takes up less space on my counter.

So what happens on the first day of the RTR? I run into a friend who had bought that exact same microwave for all the reasons I listed but decided he didn’t use it enough to keep it. It was practically brand new (he had used it three times) and he wanted to sell it!

So a deal was quickly struck and now I am the owner of my dream microwave. It works exactly like it would if I were plugged into the wall at home and I am having no problem at all powering it off of my solar panels; even in January with its short days.

Why I wanted a microwave.

I must say I’m delighted to have it. In the long run it will save me a little money because I’m cooking with free solar power instead of propane, but cooking with propane is so cheap it will probably never pay for the PSW inverter and the microwave. A bigger advantage is that when it’s hot I don’t have to pump heat into the van with the propane stove.

But it will save me money in the long run if I use it instead of going out to eat fast food or at a restaurant. And I’ll be healthier!

Like many of you, I don’t enjoy cooking so I tend to eat a few things that are easy to prepare over and over again. I soon get sick of them and start craving something that’s tasty, fast and easy, that’s when I find myself at Burger King for a burger and fries because it tastes great and it’s so very fast and convenient! But with a microwave at home I can have great tasting food available instantly. It’s actually even faster and easier than Wendy’s because I don’t have to drive into town and stand in line to get it. I just open the fridge, throw it in the microwave, and a few minutes later it’s ready to eat.

Fortunately, there are now numerous frozen meals and other things that are reasonably priced, good tasting, easily microwavable and are also fairly healthy. That’s a win-win to me and if it can keep me out of MacDonald’s I come out way ahead in both my wallet and my health.

micro-watts-highight

How Much Solar—Doing the Math

You’ve probably heard people say it’s impossible to run a microwave off of solar panels but that just isn’t true.  With 400 watts of solar and 4 golf cart batteries you can use a microwave. Let me prove it to you.

First, let’s clear up a common mistake; many people confuse cooking power with the power draw of the microwave and think that since it has 700 watts of cooking power it only draws 700 watts from the inverter, but that’s not true. If you look at my photo of the electrical plate of my microwave, you can see that it clearly lists the two numbers as power input and power output. The input is 1200 watts drawn from the wall plug and output is the 700 watts put into your food. So its draw from the batteries is 1200 watts or 100 amps per hour. Actually, when you consider inverter inefficiency of 20% it’s more like 120 amps an hour.

My Xantrex 2000 ProWatt PSW  inverter is mounted in my van because it has 380 watts of solar and 4 golf cart batteries.  The microwave is in my trailer and I use a 10 gauge, 25 foot outdoor extension cord to plug it in.

My Xantrex 2000 ProWatt PSW inverter is mounted in my van because it has 380 watts of solar and 4 golf cart batteries. The microwave is in my trailer and I use a 10 gauge, 25 foot outdoor extension cord to plug it in.

That’s a lot of amps! Microwaves draw 120 amps an hour out of your battery and that is such a huge number you automatically assume it’s impossible to use. But what people fail to take into account is how little it’s being used. If it’s only on for few minutes a day, we need to find it’s amps per minute, not amps per hour.

120 amps per hour divided by 60 minutes means it only draws 2 amps a minute—which is a very small number!  Because I usually only use it 5 minutes a day, and never use it more than 10 minutes a day, it only draws 10-20 amps off my batteries per day. Since I have 6 golf cart batteries I have a total of 700 ah and I can safely draw 350 per day, 20 amps for the microwave is such a drop in the bucket that I don’t even know it’s gone.

There is one more consideration though. When the power draw is that fast it can drop the voltage of the battery so low that the inverter will shut off automatically, that’s why you need at least 4 golf cart batteries and only two may not work. My microwave will work off just two golf carts, but my inverter starts doing a buzzing sound that I don’t like. So I have the two banks of golf cart batteries connected by an On-Off switch and connect them together when the microwave is on.

So if you’ve been wanting a microwave but thought it wasn’t possible, it is. Because most of us are on a tight budget, I recommend you try adding a piece of the system as you can afford it and then after a few years you’ll be in business.

  • Step one, add a 200 watt solar kit and batteries. Currently $340 at Amazon: Renogy 200 watt Mono Kit
  • Step Two, add a 2000 watt Pure Sine Wave Inverter. Currently $375 at Amazon: Xantrex PROWatt 2000 PSW Inverter
  • Step three, add a second 200 watt solar kit and batteries. Because the batteries will be a different age than the other set they can’t tie together permanently or the newer set will be damaged. I connected mine with a 4/0 gauge wire and put an On-Off switch in it. They charge separately and are only together when the microwave is on.
  • Step four, buy the microwave. Currently $150 at Amazon: Whirlpool Compact Microwave

Welcome to the modern age of vandwelling!

Bob
About

I've been a full-time VanDweller for 12 years and I love it. I hope to never live in a house again!

31 comments on “How to Add a Microwave to Your Van
  1. Calvin R says:

    There’s an interesting puzzle piece filled in. I shall have to see how my life goes, but I use a microwave for everything but pasta. (I eat a lot of pasta.) The microwave would not only save time and inside heat, it would cut back on condensation and make ventilation easier or less needed. Do you buy frozen food as needed or do you have some way of keeping it frozen?

    • Bob Bob says:

      Calvin, I do have a large fridge but not a freezer. I just buy it and throw it in the fridge and I’ve never had a problem eating it 4-5 days later. It takes a day to thaw and it stays good refrigerated no problem. You do have to get new stuff every week but I generally go into town once a week.

      Cooking it thawed has no impact on it’s taste or texture. It just cooks faster.
      Bob

      • Calvin R says:

        I never thought of that. Thanks! I will be in towns two or three times a week minimum because of recovery. I don’t have clear details yet but I’m getting a better picture of what I would do if the details work out. It would look a good deal like the minivan setup I was using for travel and camping with my wife back in ’06 and ’08. Now to fit the microwave setup into that.

      • Lucy says:

        Bob, @ microwave oven is NOT a luxury but a necessity, using one you’re quickly able to heat up H2O to make a cup of coffee, or tea when is cold & u’r ‘ tuje is frozen ‘ for example, or heat up left overs & / or TV dinners… Microwaves are an efficient, quick & practical way to have better quality of life at home or on the road.
        Good, U got one, enjoy it !! Lucy.

  2. Dave says:

    I still live in a stick built house and don’t have a microwave. I know its almost unthinkable in 2015, but we manage. I really don’t eat frozen food, and found when we had it that I was mostly using the microwave to heat leftovers up. Well, that’s easy to do on a stovetop. Add a (very) little water to the bottom of a pan, get some steam going and then add your leftovers and stir, then turn the heat down. For 99% of the food I eat that works just fine.

    But I’m glad you found a good deal on a used one and it works for you. And, if it keeps you out of McDonalds you will save money on your health in the long run. Its difficult to even call what Mickey D’s serve food, its more like “food-like” stuff that will pass through your body, eventually.

    • Bob Bob says:

      Dave, that’s all true, but when you live in a van all the little things conspire to take longer and be harder. Cooking and cleaning both are more difficult in a van. I’d guess you have a hot water heater, a tap with running water and a dishwasher–I have none of those things. That’s not a complaint, I really don’t miss them. I get my conveniences where I can and where I think they are most important to me. Putting food on a paper plate in the micro means no cooking and cleaning.

      Of course I’m wasting a paper plate. But, trees are renewable and the amount of energy I don’t waste every year on a hot water heater, dishwasher and indoor plumbing is a million times more than offsets the damage done by the plate! And of course the electricity was free from the sun–unlike the fuel on your stove top and hot water heater.

      Sometimes you have to look at the big picture of how the many pieces interact.
      Bob

  3. tommy helms says:

    Mmmmm….microwave burritos.

  4. jonthebru says:

    Some really great posts and comments lately folks. As Bob and others have shown, living well and efficiently can be done for a reasonable cost and reasonable effort.

  5. Ming says:

    this is evil, I am trying to keep my plans simple and minimalist so I can have a small vehicle!

    Just kidding, your home is very ingenious in how you have figured out what is important to you and how to make it happen.

  6. JimS says:

    Hi Bob,
    I wanted to mention one part which may be a little misleading. When you did your power calculation, you concluded that you’re only consuming a couple of amps (120 amps / 60 min). But you’re really consuming a continuous 120 amps for those few minutes from the battery. I think using amp-hours to calculate consumption is a bit tricky. I liken it to an MPG rating on a car. It’ll vary depending on how you drive it.

    The main reason I bring this up is someone may think they can get by with a smaller setup than they really need. If someone’s adding power to their rig, they need to size both their batteries AND cabling to accommodate that load, short as it may be.

    Regards,
    JimS

    • John Dough says:

      I noticed that calculation as well.

      But I guess it’s the simplest way to approximate usage, since storage capacity in batteries is rated in amp-hours.

      But perhaps drawing 120 amps for 2 minutes would use more than 2 amp-hours of storage, due to the high current draw.

      But I’m sure Bob has some headroom in his capacity, the beauty is it works, and if he runs low, he merely has to sit tight in the sun and let the free energy recharge his batteries.

      • Bob Bob says:

        John, you’re right it is more than I said because of Peukert effect. But you’re also right that it’s such small total numbers that it doesn’t have much effect. There’s plenty of leeway for it.
        Bob

    • Bob Bob says:

      Jim, I’m not sure I know what your point is. I think anyone with 400 watts of solar and 4 golf carts can easily run a microwave. That’s exactly what I am doing and I’m sure anyone else can. After i run the microwave it bounce right back to 12.6. But more importantly the next morning after resting it’s still at 12.6. The draw off the battery is negligible.

      You’re probably referring to Peukert’s law which states that the higher the draw from a battery the more it takes per unit of time. It’s higher math, and beyond me, but there is no doubt that it means that it is more than 2 amps per minute. But it’s not that much. Let’s be extreme and say that it doubles it from 2 amps per minute to 4 amps per minute. It’s still well within the capacity of my system. My uneducated guess is it multiplies the draw by 1.3 or 1.5, probably 3 amps per minute or less.

      You do have to be very careful to use the right size of cables–if you buy a quality inverter it will tell you what to buy. Mine called for 2/0 and that’s what I used. To connect the two batteries together I used 4/0 because I got a good deal on it.
      Bob

  7. Chester says:

    In my s&b i have a microwave in the upstairs bathroom as well. My main use is heating my neck pad. One clean cotton sock. two pounds of whatever dry beans or peas are the cheapest. Fill sock with beans, and tie off the open end. Three minutes in my 700W, a couple of aspirin. sock around neck and to bed. Best cure for what Uncle Sam left me. You know this latest build will have a microwave.

    • Bob Bob says:

      Chester, every so often I get a stiff neck and it hadn’t occurred to me to use the ole beans in the socks trick–I’ll have to remember that!
      Bob

  8. dave says:

    The inverter technology behind Panasonic and G.E. microwave may be a big plus as they throttle back the wattage based on power level – eg. 1200 watt microwave running at 50% power level will run at 600 watts continuous instead of 1200 watts 50% of the time.

    • Bob Bob says:

      dave that would be a big plus. I’m happy with my whirlpool because with a 2000 watt PSW inverter I have enough power to run it at full power.
      Bob

  9. Alan wade says:

    Thanks for the info bob. What do you think of buying & installing 1 or 2 12 volt agms and the 2000 watt inverter now. Wire it with big wire & isolator to van. Add solar later as I can afford it? I would love to bring my little nespresso machine with…

    • Bob Bob says:

      Alan, as long as the engine was always running when you used it it would work, you’d need to run it after to recharge the batteries afterwards.
      Bob

  10. Thomas Popple says:

    There is a solution to getting a microwave without having to have so much solar. If you set your house batteries to either charge from the solar panels or the alternator you can easily start your vehicle for the few minutes you are using the microwave. Power problem solved. Pure sine wave inverter is a must though.

    • Bob Bob says:

      Thomas, yes, you’re right that will do the trick. You’ll need very heavy cables to carry that much power that distance (I’d suggest 4/0) and you can expect your starting battery and alternator to suffer for it.

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