Let me begin with one thing, don't have the Airstream dealer install your solar and don't go with an Airstream factory kit. If you don't want to do your own, get a company or installer with a good reputation and previous installs on Airstreams. Some panels are not made for the rigors of travel so make sure that your panels are built for non stationary use. Mine are Samsung but there are a ton of good ones out there.
I did my own install. I have four 80 watt panels, a great charge controller and inverter. We have had this set up for 10 years on our 22ft International and have not used our generator since. We have camped for more than an accumulated year with this set up. Last year, we camped for a solid month in the cold with our DVD and TV going each night along with the furnace running almost all night long. Never ran low on power. We do have to conserve after a few days if we are ever in the dark dark shade but that has only been once or twice.
It is easy to do if you know or learn how to do the install but that takes some research. I met a full time couple with a 27ft International who are living and traveling full time in the trailer. They also had 4 panels and had them installed professionally in Oregon. Here is a link to their story with the name of the installer in the blog. Their only problem was that they had more charging power than battery storage ability. Still, they had good luck overall. The Scenic Route: Here Comes the Sun! Our Solar Power Installation
Some things that are missed by most installations is a mild galvanic corrosion over the years from screwing stainless steel into aluminum. The US Navy uses something called T-Gel to coat any stainless steel screw going into aluminum. T-gel is available in small quantities on the net.
Installing the panels was easy. I used rubber expansion bolts. Where there are rivets, there are solid frame tubes to mount to. Since the roof is curved, there is a Z shaped bracket made from aluminum that can be easily bent for a bracket flush mount.
I used the pre-wire from already installed by Airstream. The beginning of those wires are usually tucked in behind the fantastic fan and come out near the buss. Most folks here recommend a thicker wire than the pre-wire but I've had no problems. The panels are wired to a junction box on the roof with its own buss. Several people told me to make sure to use the exact same length wire from each panel to my junction box amid claims of efficient use of the panels. Don't know if they were right but it can't hurt anything and nothing has gone wrong in 10 years and the panels work great.
From the roof junction box, you must access the pre-wire inside the trailer. There are lots of holes to drill in your roof with a solar install but taking the wire from the roof to the interior is the scary one. I used a wire "clam-shell" fixture from West Marine that is used for the side of sailboats for cable wire install for TV access while docked. Great little device and very waterproof.
Now that your inside, securely connect to the pre-wire by taking the bottom of the Fantastic Fan off. The big thing here is to know where the Pre-wire is for sure. Mine was in the roof to the side of the Fantastic Fan which made this connection easy. The folks at Airstream Customer Service went to the factory to make sure that this is where my wires would be and got back to me in a few hours and bingo. Know where the Pre-wire starts. If you want thicker wire as many recommend, post something here and ask how to do that.
Now that the sticky stuff is done, connect to your charge controller. Don't skimp here. The charge controller is really important!!!!!! I recommend an MPPT controller. Maximum Power Point Tracking Solar Charge Controllers (MPPT) are different than the traditional PWM solar charge controllers in that they are more efficient and in many cases more feature rich. MPPT solar charge controllers allow your solar panels to operate at their optimum power output voltage, improving their performance by as much as 30%. Traditional solar charge controllers reduce the efficiency of one part of your system in order to make it work with another.
May I also add at this point that inline large buss fuses are nifty on between all connections. I did have one blow between the controller and buss one time around five years ago.
Once you have your inline fuse in, connect to the main buss. The switch on the wall that disconnects the battery to the trailer still works as intended and the batteries will still charge. A good controller will help the batteries last longer.
Now for the bummer, I mentioned the full time campers with not enough battery storage. This is the biggest problem with solar camping if you really want to use full time solar without restrictions. You really need to educate yourself on battery maintenance whether you do the install yourself or have a professional do it. You can add more batteries or use bigger batteries. The batteries need to be well ventilated. Lots of panels may charge better in the shade but the charge controller will shut off juice except for a trickle if the batteries are fully charged. Most people use electricity when the batteries are not charging at night (especially the furnace).
Whether you add batteries or switch to bigger batteries, you will have to decide where to put them. I have 2 huge Trojan 6v 435AH which is overkill and adds tongue weight. The box that Airstream installed on your tongue is useless for increasing battery capacity. I built a bigger box.
Also, for the life of me, I can't understand why Airstream goes with those 30lb propane tanks instead of a standard 20lb tanks. In a tight spot, the 20lb tanks can be traded with Amerigas or Rhino at the grocery store but with the 30lb tanks, you need someone that has a filling station. The 30lb tanks full add about 16lbs of extra tongue weight at the furthest point from the trailer. If you want to increase the size of your batteries, that weight could be better used.
In closing, this is what I did and this is what has worked for about 400 camping days in all kinds of weather. We've also found the solar to make a handy emergency home in the trailer during power outages, one of which lasted three days in our town.
There may be better ways to go about this but it worked for me and cut the price in half over hiring an installer. If your worried about the difficulty, it's not that hard once you get the knowledge. I did most of my install under the influence of Tequila and it was still easy.
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