Jun 12 2018

Cooking without gas (or charcoal!)

I like trying new things as we travel in our Airstream. Last week, at Alumapalooza, I saw an earnest Welsh man named Davey Jones (really) demonstrating something I’ve never seen before: a solar cooker that actually makes sense.

I have seen solar ovens before. Back in 2005 at the Florida State Rally I spotted someone cooking with a giant solar oven (pictured at right) but I was unimpressed. Although the oven had room for a large pot, it was far too big to be practical for our style of travel. When deployed, it looked like an NASA probe bound for Jupiter. I dismissed it as an interesting but quirky niche item for extremists.

Thirteen years later, I’m not so quick to dismiss the power of the sun. After all my fixed base home and my Airstream are powered by solar panels, and I love them. At home the sun provides 110% of our annual power needs, and solar panels can keep us unplugged for weeks during the summer in our Airstream.

Davey was showing off the new GoSun line of solar cookers at Alumapalooza. (They’re called “cookers” because they can be stove, oven, broiler, steamer, or water-heater depending on how you use them.) Even in hazy Ohio sunlight he was baking up cinnamon rolls and frying bacon all day long. I’m not sure if I was more impressed at the cooking or the cleverness of his olfactory marketing.

The secret of the GoSun cookers is the vacuum tube at the center. It’s basically a Thermos bottle with one-way mirrored glass. Sunlight goes in, converts to infrared as it passes through the glass, and the heat is trapped by the vacuum bottle. This is a quantum leap from the big wood box of 13 years ago.

That means that with the GoSun cookers you don’t need a huge reflector area to make a lot of heat. The reflectors on the GoSun cookers is tiny compared to the giant Sun Oven pictured above, and yet the inside of the vacuum tube can get to 550 F. (Most of the time it runs 200-360 F.) The amazing thing is that you can grab the outside of the glass tube with your hands and it won’t even be hot. So you can’t burn yourself on it.

The smallest model, the GoSun “Go” (pictured below) is so portable it fits easily in a daypack, and weighs just 2 pounds. It’s perfect for meals for one person, or two people depending on what you cook. The next size up, the GoSun “Sport” (pictured above) is still very packable, and can make enough hot food for 3-4 people.

We got the “Go” model to try it out before adding it to the Airstream Life Store (as I do with every product we carry), and tried it out in a friend’s driveway a few days later. I decided to bake some apples for my first trial, and sweeten them with cinnamon, xylitol, and nutmeg.

Whatever you cook has to fit into the cylindrical cooking tray. In the case of my apples, that meant peeling them and cutting into chunks. Then I just put the apples into the tray, slid it into the cooker, and placed it in the sun.

The cleverness of the GoSun design started to become apparent when I did this. The hardshell case of the “Go” model is zippered, so deploying it is simply a matter of unzipping. A brace holds the two sides of the case open and the reflectors are built right in. There’s even a little dial attached to the tube to make it easy to locate the optimal angle to the sun, and an adjustable folding stand attached to the case props the whole thing up.

Once you slide the food tray in and point it at the sun, your work is done. After a few minutes in full sun the interior will be hot enough to start cooking. Steam begins to waft out of the end of the vacuum tube. You can take a peek at progress by sliding the food tray out for a moment.

My big mistake was not believing what I saw. I really couldn’t believe that the apples were cooking, so I left it in the sun for much longer than necessary, and when I finally removed them they were basically applesauce. Delicious applesauce, sure, but not quite what I had planned for. Fortunately, I had prepared three apples and could only fit 1.5 apples worth in the first batch, so did a second batch and cut my cooking time in half.

Those apples came out perfectly, softened but still firm. I mixed the chunks with the applesauce from the first batch and had a really great dessert for the next two days. (It would have been perfect on ice cream but I ate it all straight.)

Now, you may be thinking “I already have a stove and oven in my Airstream, so why do I need this?” I thought the same thing at first. Then I realized, a big part of the joy of travel and camping is cooking outdoors for family and friends. Lots of people carry charcoal or propane grills. Others carry Dutch Ovens. You don’t need them but it’s so much more fun to prepare a meal slowly, outdoors, and while you’re waiting for that delicious slow food you can enjoy talking with your friends.

I particularly like that the GoSun cookers come with little silicone baking trays so that you can make cupcakes and such (I used them for the apples, too), and can be configured to make hot drinks. This gives them a lot of versatility. They’re also easy to clean; you just slide out the stainless steel tray and wash it. GoSun includes a bottle brush to clean inside of the vacuum tube if it gets a little food stuck to it, but most of the time that’s not necessary. So cleanup and packing took me about two minutes.

The only limitation I spotted with the “Go” model is that the food capacity is pretty small, best for one person or a small side dish (or a topping like I made). I think we’ll upgrade to the “Sport” model for future cookouts, and that way we can make things for all three of us. If you get the Sport, be sure to get the “Pro Pack” so that you have all the accessories you need including a case.

If you have one of these, please put in a comment below to tell me your favorite thing you’ve made in it. I’m looking forward to further experiments with our portable solar cooker, and your ideas would be welcome!

GoSun cookers in the Airstream Life Store with free shipping

Nov 03 2015

Solar vs Generator?

Lots of new Airstream owners want to find ways to extend their camping time while “boondocking,” (off-grid camping, away from electrical hookups). So inevitably the question comes up: which is better, a generator or solar panels?

The answer comes down to your needs. Generators are the most practical way to have enough power to run very high-wattage appliances like the air conditioner and microwave oven. If you must have air conditioning when not plugged in, you will have to use a generator, and it will need to be capable of at least 2,000 watts peak output, and preferably more.

However, if you can live without your air conditioner and microwave oven, solar panels become a very attractive option. Solar panels are silent, don’t require you to carry fuel, and are virtually maintenance free (other than washing them once in a while). They work without any intervention from you and can keep the batteries in your Airstream charged while it’s in storage.

A major difference is that solar panels only provide power to charge the batteries. They don’t directly power anything, although the batteries will of course power all of your 12-volt devices and can even power low-wattage 120-volt AC appliances like laptops and TVs using an inverter.

Most RV generators have on-board inverters so that they can provide 120-volt AC power directly to the Airstream, just like plugging in. This is convenient but most of the time the generator is producing far more power than you actually need.

If you want a generator primarily to recharge your batteries while camping off-grid, you can get the smallest generator possible. Even a small 1000-watt (rated) generator can typically produce far more power than the batteries will accept at any given time. The rest of the power is wasted, unless you are running the microwave or some other power-hungry AC appliance while the generator is running.

This means that the best time to use the generator is when power demand is high. It’s much easier to avoid using battery power by being plugged into the generator, than to try to recharge battery power later. Use the generator in the morning and evening when you are cooking and using lights and water pump, and the power needed will be supplied by the generator rather than coming from the batteries.

If you want to get a generator, do yourself and your neighbors a favor and get one of the quieter models specifically made for RV use. Both Yamaha and Honda make excellent products which have good reputations for reliability and quietness. If you borrow a “construction” generator from work on your weekend camping trip you will save some money but you won’t be popular when you fire it up—and the noise might detract from the peacefulness of your boondocking site, so what’s the point? Similarly, there are cheaper “knock off” brand generators on the market, but their quality is not up to the standards of the major brands.

Solar’s big advantage is in recharging batteries, so if extending your time at camp is your primary goal, they are the preferred option. Rather than pumping out large amounts of power in short time periods like a generator, solar provides a steady all-day charge will have a much better chance of getting your batteries up to 100%. It’s like the turtle and the hare. With batteries, slow and steady wins the race.

If you have both a generator and solar panels, use the generator when the batteries are heavily discharged (for an hour or so in the morning, for example) to get the bulk charge done quickly, and then let solar finish the job over the course of the day.

If you only have solar, keep in mind that during the morning and mid-day, moderately or heavily discharged batteries will probably accept every amp the panels can generate. Then the charging rate naturally slows down. If the sun is still shining at that point you have surplus power, and so that’s the time of day to plug in all of your rechargeable accessories like phones, cameras, laptops, etc. This strategy takes maximum advantage of the power being generated.

Sometimes people go with generators over solar because they are afraid they won’t have power on a cloudy day. Certainly clouds will drastically reduce the amount of power generated, but you’ll still get some. The solution is to add batteries so that the Airstream has enough power to bridge a cloudy day (or two) without a problem.

If you are considering adding solar panels, keep in mind that the solar panels should be sized to approximately match the capacity of the batteries in the Airstream. If the panels produce a lot more power in a typical day than the batteries can store, you’ll have wasted money on expensive panels. If the panels are too small, they might not produce enough power to keep the batteries charged, which can lead to short battery life if the trailer is not plugged in regularly (such as during long-term storage).

It’s hard to do an apples-to-apples comparison of generators and solar panels, because as you can see, they perform very differently. It’s even hard to pin down a cost for comparison, because the output of each option can vary widely. Quiet RV generators from Honda and Yamaha range from 1,000 watt units suitable for battery re-charging and small appliances, up to big 3,000 watt units to run the air conditioner. Solar panel systems (including battery banks) can run from 50 watts up (typically 200-400 watts will fit on the roof, plus more possible using portable panels), and the costs of an installed system are likewise varied. Keep in mind that comparing wattages is not useful since the solar panel runs whenever the sun shines, and the generator usually only runs for short times.

You’ll need to decide which option you prefer, and then talk to a solar installer, or shop generator prices. RV solar specialists are in many parts of the country (some are even mobile and will come to you) and they can help determine the optimal size of your battery bank and provide solar panels to match.

Either way, upgrading your Airstream to give you more boondocking time is a great advantage. It will open up new travel options for you and eliminate worries about running out of power when on a long trip or during storage.

For more, pick up your copy of Rich Luhr’s books, “The Newbies Guide To Airstreaming” and “Airstream Life’s (Nearly) Complete Guide To Airstream Maintenance” at the Airstream Life store.

Dec 01 2014

Questions and answers about power, batteries, and solar

Solar power, shore power, generator backup…the configurations are as varied as the number of rigs on the road, and the answer to most power questions is “it depends”.

While each Airstream is uniquely outfitted, many Airstreamers have common queries. Following are answers to questions posed at one of our recent Aluma-events.

I’m a solar user, but what happens to my batteries when I plug in to shore power?

Your solar panels are still active when you use shore power, and a built-in regulator prevents the batteries from overcharging. Put simply, solar panels always produce power when exposed to light, and that power is sent to be stored in the battery. Shore power (AC, which gets converted to DC) also goes to the battery, so both sources are working to keep the batteries charged. One source might contribute more than the other, but it’s all good power input.

How can I extend my battery life?

Baby it. Your battery will last nine years and counting, depending on how it’s maintained. If you’re plugged in often, it’s a good practice to check the battery water every 30 days. Pop the caps off and fill them up over the lead plates; otherwise, they’ll sulfate and corrode the other batteries. A dead cell in one battery will drag the other battery down with it, over time.

If it freezes outside in winter it won’t last it’s full life expectancy. Don’t leave it dead; if the electrolytes aren’t excited in the battery, they’ll freeze. Take your battery out and let it winter over in the garage.

Can my family multitask in the trailer?

Yes, but to a reasonable limit. If you’re using a curling iron, the air conditioner, and a microwave all at the same time, you’ll draw too much and flip the breaker. Overloading the outlets (a.k.a. AC power system) with too many plug-in appliances will trip the circuit breaker.

DC power differs, and if your battery has drawn down too low you’ll have trouble with the vent fan, lights, or water pump—and there’s no circuit breaker on the DC power system. When lights dim and the pump and fan are sluggish (or non-working), it’s past time to recharge. Try not to draw the batteries down more than 50% between charges, because doing so will shorten its life. Consider installing an amp-hour meter to more accurately keep track of the power in your batteries.

Where is my converter? And what does it do?

Your converter changes 120 volts AC shore power to Airstream appliance-friendly 12 volt DC power, and prevents your Airstream battery from draining. You’ll have to snoop around to find it, as the location depends on your Airstream floor plan. Often the power converter (a “black box”, literally) will be installed under the refrigerator or sofa, or inside the closet. Open the door and you’ll see the 110 breakers and fuses inside.

I want to go solar. How much do I really need? How much does it cost?

These and other questions about solar conversion are like asking “how long is a rope?” Answers will vary, depending on the panel size and watt capacity. Some users claim that one hundred watts of solar provides enough power for a family; others require nearly three times that amount.

Your location and weather play an important factor as well, as the battery charges through the day for the night, and recharges the next day—and the more panels you have, the merrier you’ll be. The number of permanently-attached solar panels you can accommodate depends on your Airstream model and the available real estate on the roof.

What’s that rotten egg smell?

Could be the converter is overcharging the battery, but more likely you have a battery low on water (assuming it uses water). Allow the battery to cool before adding more water.