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.

AC Maintenance

Feeling hot in your Airstream? The quality of cooling you get from your rooftop air conditioner depends a lot on what you do. In normal operation, the air conditioner can produce air that’s about 18 to 22 degrees cooler than what goes into it. That means if the interior of the Airstream is 100 degrees, 80-degree output air is about the best you can expect initially. As the air recirculates, the temperature of the output air will drop. To get the best cooling, do what you can to park in shade, and follow these tips:

Insulate

Close curtains, shades, and blinds. Put insulation to your windows, vent fans and skylights. The “bubble wrap” type of insulation with silver coating works well and can be cut to fit.

Seek shade

If you can’t park in shade, try to park on gravel or grass. Put out your patio awning and window awnings if you have them.

Stay cool

Cook outdoors or use the microwave oven to avoid adding heat to the trailer. Limit use of incandescent lights—each one of them is like a little 10-watt heater.

Monitor voltage

“The best thing you can do for the long life of your air conditioner is to feed it the proper electrical voltage,” said Rich Luhr, author of Airstream Life’s (Nearly) Complete Guide To Airstream Maintenance. “Low voltage is bad news for the compressor.” Don’t expect your air conditioner to start with less than 103.5 volts, and running it on a day when the campground voltage is less than 108 volts is risky.

It only takes a short “brown out” to drop the voltage below a safe level and cause damage, and it can happen while you aren’t looking. This is one reason why you should have an AC voltage monitor somewhere in your Airstream, or an electrical protection device that cuts off the power when the voltage is too low.

Even newer campgrounds can have voltage problems. If it’s a hot, humid day and everyone is running their air conditioning full blast, be wary and check the voltage. Likewise, don’t run your air conditioner on a household extension cord or a household 15-amp outlet because that will add to the risk of low voltage.

Maintenance matters

Don’t use an extension cord rated for less than 30 amps (50 amps for Airstreams with two air conditioners), and never use a household (15-amp) outlet. Keep filters, condenser fins, and all other parts clean. “The last two tips are the ones people ignore the most, and that’s a shame because they are really the most important,” writes Luhr.

To maximize the efficiency of the air conditioner, clean dust off the filters regularly. Dust builds up quickly and can severely reduce the amount of cool air you get. Also, dirty filters cut down the amount of air that can circulate and will encourage frost to form on the cooling coil, which means the air conditioner is more likely to ice up.

Depending on the model of air conditioner you may have two knobs and then two screws to drop the shroud (older style), a pair of surface-mounted plastic vents with tabs to release, or a pair of small filters that can be slid out from the front.

Airstreams with ducted air (25-foot and longer trailers starting with model year 2015) have filters located above the return air grills in the ceiling. Replacement filters are available from Airstream dealers, part #382236.

To remove the return air grill on a trailer with ducted air conditioning, just pry it out with a non-marring tool at the short edges of the screen. The filter lies atop the grill.

While you’ve got the filters out, look inside for excessive dust, bugs, cobwebs, or other debris. You can vacuum this out with a brush attachment. Most filters are washable, so you only need to replace them when they can’t be cleaned or when they get torn.

View from the top

If you want to go further, take a look at the air conditioner from the roof. First, remove the shroud (just a few screws) in order to get a good look at the condenser fins and compressor coils. You can spray the fins with a water hose or compressed air, from the inside out, to clean them up, and bend the fins straight again. There’s a tool called a “fin comb” that can be used for this. Check for mold, wasp nests, and dirt, and clean everything.

If you suspect problems with the air conditioner, it’s probably best to take it to an RV technician. The tech will compare the incoming air temperature to the outgoing air temperature (the “temperature delta”) to see how well the unit is cooling. Other checks include a more thorough inspection of the components, checking the amperage draw, inspecting the condensate drain, the condition of the roof pan and mounting bolts, and perhaps oiling the fan motor.

For more about air conditioning and other invaluable maintenance tips, order your copy of Airstream Life’s (Nearly) Complete Guide To Airstream Maintenance. “Maintenance of your Airstream is not nearly as difficult as most people think, and with just a few basic tools and this guide, you can do almost every routine task yourself,” states author Luhr. “No more trips to the service center for every little thing, and you might even find that this book saves one of your vacations, if something goes wrong on the road!”

How to improve your battery charging while boondocking

Nancy in Casa Grande, Arizona has questions about battery power:

“We are interested in upgrading the battery in our Airstream, and the converter to one that will charge via the generator better than the factory model. We want the battery to last longer when we dry camp, and have a converter that charges without running the generator for hours on end. The Xantrex was really overkill for us and the price for the amount of time we spend dry camping seemed a bit high. Is there a less high end unit available (we really don’t need a lot of the features)?”

Nancy, good question—and you’ve actually asked two separate questions. First, no matter what type of battery you use, it can only put out as much power as it can store. So to get more camping time when “off grid”, you need larger capacity batteries or more batteries (or both). Look at the “C/20” amp-hour rating of batteries—the higher, the better.

The trade-off will be increased weight, size, and expense, so think carefully about how much power capacity you need. Also consider where larger or more numerous batteries will fit in your Airstream. A professional solar consultant can be very helpful here.

Your second question was about the converter/charger. Upgrading the converter/charger won’t dramatically speed up the charge rate of the batteries. The battery is the primary limitation when it comes to charge rate. A “3-stage” charger will help a little, but you’ll still be running the generator for hours to get the battery full.

TriMetric 2020
TriMetric 2020

A better choice for frequent boondockers is a solar panel in conjunction with your generator. Use the generator for short “bulk” charges when the battery is low. Turn the generator off when the battery reaches about 80% or the charging rate slows down to a trickle. Then let the solar panel do the rest of the work over the course of the day.

You’ll need to install a good battery amp-hour monitor so you can see the battery charge rate, which will add about $200 to the tab, but for extended camping without power hookups it’s well worth the investment.

Are surge protectors really necessary?

Are surge protectors a necessary expense to protect the electrical systems of the Airstream?

Surge protectors and related electrical protectors are like insurance policies: you only need them when something goes wrong, but you have to buy them in advance if they’re going to be of any use at all.

A basic surge protector can stop a sudden electrical spike from damaging electronics in your Airstream. More sophisticated power protectors can do that as well as protect against unsafe conditions like incorrect wiring, or low/high voltage conditions that might burn out your air conditioner or microwave oven.

Most campgrounds have good wiring, but if you travel a lot you’ll eventually run into a shoddy-looking receptacle with bad wiring, or find a campground that is struggling to maintain proper voltage to all the campers (especially during air conditioning season). Since you can’t be there to monitor the power all the time, a good power protector is a wise choice. Expect to spend about $200-300 for a quality unit.

 

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.