Solar, Wind, and other Alternative or Renewable Energy for Motor Homes

[Ralph Javins]

Good morning, all;

     This note is an exploratory effort to determine if there is any interest here in talking about photovoltaic solar panels, wind generators, solar hot water heating, passive solar energy control methods and techniques, and other similar subjects as they may be applied to motor homes.

     Jimco has been asking that we create discussion groups in the new Groups for motor homes.  As with most others here, I do have a Winnebago, specifically a 1987 Winnebago Elandan WCP31RT.  It had belonged to a young lady I had worked with and flew with, but when she died, I bought it from her estate.  It did need some work, but it is coming along nicely in its restoration and there are many upgrades and modifications going into it.

     One modification that might be of interest to others here is the addition of photovoltaic solar panels on the roof of the Winnebago Elandan to make keeping the batteries charged while parked very easy.  It also means that "boondocking" is a much simpler process.  Solar power does make extending the time that we can be out away from other sources of power quite a bit longer.  And there is also the ability to plug into the coach 12 VDC electrical system a small wind generator that is mounted on its own tripod and mast.  It is not physically mounted on the motor home because the vibration and noise of the wind generator will be transmitted right through the frame of the motor home, and it will keep you awake at night when the wind is blowing.  

     A question that might arise is one about why I feel that I can offer information on solar panels and other things related to alternative and renewable energy.  For a bit of background information, I built my first solar panel back in February of 1962, eight years after the guys at Bell Labs introduced Solar Panel Serial Number 0000001 to the world in April of 1954.  I have been using solar panels for running my 100 Watt short wave radio transmitter when I have gone off to play radio on islands where there is no other source of power.  My solar and wind powered radio station has been displayed for many years at such venues as the NorthWest Renewable Energy Fair in Shoreline, Washington, the SolWest Renewable Energy Fair in both John Day, Oregon, and La Grande, Oregon, and other places.  Now I have installed and I am upgrading the solar panel installation on the Winnebago Elandan.  

     While I will not claim that I have the definitive answer to all things related to solar power for a motor home, I can at least talk about what I have done, why I chose to do things in the way I have, and the rationale and logic for my decisions.  I can also address why I did not do some things in that way.  I will admit that a mobile solar panel installation on a motor home is not the same as putting solar panels on your house.  There are many other factors to consider when deciding how you are going to do such a project on a motor home.  We can talk about those.

     I should also say that solar power is not something that will do everything that you want in a motor home.  While there are a lot of things that we can do with it, there are many things that are not practical to try with the limited real estate there is on the roof of the average motor home.

     So, is there any interest in such a discussion?

          Enjoy;

          Ralph

          Latté Land, Washington

[Rick Faunce]

I am definitely interested.

[Jimco_W001]

I think the best investment I made on my 1970 F-17 Winnebago was adding a large automatic 12 volt to 120 volt  inverter. Use the Winne's engine alternator to keep the inverter's batteries charged. Works good for me because I'm driving almost every day when I use it.

[Dawn Michelle]

I'm not a Winnebago owner, but I joined to keep track of this discussion - I plan on adding a system to my motorhome when I get her.  

[Ralph Javins]

Good morning; 

This has not been forgotten.  It is still a work in progress, including deciding how to structure a presentation into something logical and rational that can be easily followed, but using mainly descriptive words, and, hopefully, some illustrations, both photographs and line drawings.  While some of the sections are already partially written, there are several topics to be covered, and they should be presented in a step-by-step order.  When working on the outline for the subject, it became clear that there are some additional subsections to be developed.  I'm working on it, I'm working on it.  

Then there is the point about the unfortunate encounter with the deer on the first of April.  That incident and the resulting minor cosmetic repair to the motor home has taken up a lot of time in the last week, and it is not yet fully resolved, along with the other changes and improvements with the Winnebago that are part of "The Project."  And there are the normal demands of life with which to contend.  Also, there are other things happening during the time period of the year that we are now beginning.  The time for trips and gatherings is here once again. 

I hope everyone is looking forward to the coming Summer and playing with their motor home or other RV. 

Enjoy, and have fun; 

Ralph, Latté Land, Washington 

[Phillip T Rodden]

I am very interrested in using solar or wind with my 1987 Holiday Rambler class A. I am still getting it " Road Ready " . It sat for a few years.  As soon as I iron out the kinks ( replacing belts and some break lines ect......) I am planning on adding 2 100 watt panels and maybe another battery or two. I have a generator but the previous owner removed the control panel for some reason. I will repair that at some time , but I do like the idea of charging my batteries with the sun. From my limited experience with this rig I feel that I could do quite well for quite a while with just the batteries and solar power. It didn't look too hard to install from the Youtube vids I've watched. And there seems to be some decent kits through Amazon. So I am very interrested in hearing what others have done and thank you for any help. 

[Ralph Javins]

Good morning, Phillip; 

Yes, there is a lot that you can do with 200 Watts of solar panels.  That will come to about 11 Amperes at 13.8 VDC in full normal sunlight, and that really is a useful amount of electrical power.  I have run my radio transmitter off that amount of average power when I play radio on islands.  The main points will be how you mount the solar panels for mechanical security, and for being water tight over a long time period.  You are putting them on the roof.  And then there is the way that you run the solar panel output wiring down to inside the motor home to the "solar panel charge controller" (a solar industry name for their special solar panel voltage regulator that receives the 16.5 VDC to 18.0 VDC output from a nominal "12 VDC" solar panel and drops it down to the 13.8 VDC that the battery wants to see).  One really convenient path is down the refrigerator heat exchanger vent shaft.  The plastic cover on top of the vent shaft already provides most of the needed weather protection for that opening through the roof.  My charge controller is mounted inside the kitchen or galley sink cabinet.  Then the large wires are run from there to the wiring for the coach batteries.  And I did increase the size of the wiring going to the coach batteries from the 8 AWG copper wiring that was there from Winnmebago up to 6 AWG.  It does help. 

One other thing that I have available for my radios is a "voltage booster" (actually a DC-to-DC power converter) that takes the power coming from the battery, which often is just about 12.2 VDC or so at night, and "boosts" it up to the 13.8 VDC that the radio is expecting to see at its power input terminals.  And I did choose a "voltage booster" that is also RFI quiet; it does not make radio noise that will be either conducted or radiated to my radios.  This is a point of some interest to me, and I do have a spectrum analyzer that I use to look at the Radio Frequency characteristics of my systems, lighting, and accessories in the motor home.  Yes, I do use the motor home as a mobile communications station, so this quality is important to me. 

Enjoy, and have fun; 

Ralph, Latté Land, Washington 

[Dawn Michelle]

This is going to be good!  

I've been doing the armchair research.  I really would like to use the flexies since the Toys are already overweight and top heavy, but have run across a few sites that show the problems with them, too, on flat surfaces.  I also am thinking of portables because most of the time at the house the rig will be under a 'port (but I'd still like to use solar).  Just the distance I'd have to run the cord negates that unless I have two systems (and like I have that kind of money!).  Seems like there's not going to be any perfect solutions, just a careful weighing of the pros and cons.

If I could mount the flexies temporarily when we were parked (but secured) and have a way to store them when on the road...hmmm...

[Ralph Javins]

Good morning, Dawn Michelle; 

Very well done.  You are getting into consideration of just some of the additional things that are included in the current outline for this subject. 

Yes, the weight of the panels is also something to consider.  My Winnebago Elandan has a suggested total weight limit of 150 pounds for anything going up onto the roof (and it is a good thing that I am in that weight range for going up the ladder onto the roof), and there is also the GVWR or Gross Weight Vehicle Rating to be considered when adding more things to the motor home.  When I weighed my motor home the first time, I realized that I had only 760 pounds of "cargo" weight that I could put into the motor home for a trip.  With the normal suggested weight allotment of 175 pounds per person, two people comes to 350 pounds right there,  That leaves only 410 pounds for stuff.  If I fill the fresh water tank with 54 gallons of water, that is 448 pounds of water, and I am 38 pounds overweight right there.  

So what happens if I want to carry some clothes or maybe food in the refrigerator and in the cupboards?  It only gets worse.  I did check the rated capacity of the axle assemblies, the rims, the tires, the brakes, and other parts, and concluded that they are rated to carry more, and I had to make some serious changes in the rear suspension to get my GVWR up to where I can carry the things needed for any reasonable trip.  The really odd thing is that the changes made in the back are a Regular Production Option (RPO) that Winnebago had available, and they also gave you a higher rated GVWR placard with that RPO installed. 

Anyway, I calculate that now the Winnebago Elandan is good for about 16,000 pounds, or just a little more than about 1000 pounds than it was originally.  I will not need to add that much more weight for my purposes, but it is good to have that level now.  It does seem that there are so many things to consider when trying to do almost anything with one of these vehicles. 

With those considerations in mind, that is one of the reasons why I chose and bought some SoloPower flexible silicon cell solar panels made on a thin stainless steel substrate.  They are much lighter and thinner than the more common aluminum framed solar panels, so that helps with both the wind resistance and also the weight, because the 70 Watt panels are only 3 pounds, as opposed to about 18 pounds for a similar aluminum framed panel, plus there is the additional weight of the mounting hardware and framing to get them up off the roof surface.  But I do not like idea of drilling holes in the roof for mounting the solar panels.  That is another reason why I chose the thin SoloPower panels.  They literally will be glued to the roof using a thick layer of sealant.  That takes care of the wind resistance and the hole drilling problem, but it does bring up another problem; the lack of air space behind the solar panels.  That is one of the compromises that I am making; accepting that the panels will be getting hotter during the day and their power output will not be a good as it would with air space behind the panel for better heat dissipation and cooling.  If I want the low profile and the low wind resistance, that is one of the factors I must accept as part of the overall package.  While I am putting a rated 270 Watts of solar panels on the roof, I am actually expecting only about 200 Watts of electrical power from the system under normal conditions.  Engineering is always a series of compromises.  

If I can find additional panels of the specified size needed for the remaining space available, I can add about another 100 Watts to the system, and having about 350 Watts of solar power would really be nice.  There is another solar panel maker who did have panels of about the size needed, but they are also very expensive at around $10 per Watt in comparison with the SoloPower panels I bought.  $10 per Watt is like prices from back around 1990.  I bought most of my eight Solarex MSX-60 panels in the late 1990s when they were about $5.00 per Watt.  Today many solar panels are commonly available in the $1.00 to $1.50 per Watt price range, and in quantity they are less.  In a pallet quantity, they can be down around $0.50 to $0.60 per Watt.  Container quantities are even less. 

Also, your idea of using the solar panels in a "portable" configuration is quite workable.  I have done that for many years with three Solarex MSX-60 aluminum framed 60 Watt panels for operating the portable radio station out of the Subaru.  For supporting them at the chosen angle, I use adjustable "trekking poles" to hold them up, and I move them about every hour or so to face the sun as it goes across the sky.  For the current coming from each panel, the length of the wire and the wire size is somewhat "generous," but it does work.  I have also carried them in the Winnebago Elandan between the beds in the back bedroom for portable operation of that radio station under the Elandan side awning on the folding table for display and demonstration purposes. 

Time for another cup of coffee. 

Enjoy; 

Ralph,  Latté Land, Washington 

[Dawn Michelle]

I hear all that loud and clear.  I did wonder about the air space.  I think I'd be with you on that.

My biggest concern, though, is having lower places on the roof that will collect debris/water.  I don't think I have it in me to restructure a roof and I have to get myself used to the idea with any rig I find there is going to be some sagging.  And then what about replacing?  How to pull up something that's been glued down if it does get damaged?  Now on some of the toys there is a front slant I might be able to take advantage of - depending on the angle (I've never measured one).

Some of this is just going to have to wait.  But until then the more I know, the better buying decisions I can make.  For example it has more value to me if it has a generator space but no generator, potentially to put the batteries in.

Do you think those flexies could stand being hauled up and down a ladder frequently?  Being plugged and unplugged?  The ones I've looked at have grommet holes, so I could 3M some sort of hooks and then with the right protection might be able to store them in the bathroom when underway.  That and a big ole steering wheel anti-theft bar...only to remind me to take down the panels before getting on the road!

Not sure if I'm just making work for myself or not.

We had a 37.5 foot Bounder for several years and full-timed.  Never got on the roof, left that to the better half.  The worst part about full-timing was not having a place to work on things.  Remind me to tell you the story of trying to "hide" changing out a hydraulic jack on that beast in a snooty private park one night...well, it made for an adventure and we made good friends while we were at it, so it wasn't in vain.

[Jimco_W001]

   I'm thinking of buying some new solar panels for my house to charge batteries when the power is out.

Looking for the best deal.

[Matthew Tritt]

Hi Ralph,

Just now found this group. I also have long connections to solar and wind energy systems, having been in the alternative energy business since 1980. I guess I'm pretty-much retired now but still do consulting work and some sales in both disciplines, but mostly in PV these days. I originally got involved in PV when I was a yacht broker in Santa Barbara in the 70's and rented a corner of my office to a guy named Matt Voore, who invented the solar powered cabin vent for boats that sat unattended for long periods.

I've designed a number of PV/inverter systems for RV's over the years and carry a pair of portable panels in my own RV, but the rated output is only about 80 Watts. I have a 200 Watt panel sitting in the garage awaiting the time when I get over my apprehension over making holes in the fiberglass roof. ;-)

I also was the wind department head at DC Power Systems in Healdsburg, Ca for 4 years and taught our dealer network wind technology and theory all over the country (and out of it), as we were importers and distributors for the best small wind turbines on the market at the time. I'll put my $00.02 in here and suggest that using a microturbine for RV use is essentially not worth the trouble unless you intend on staying at a very windy, fixed location for some time. This is because it takes a substantial tower and guywire installation to safely install any wind turbine - even tiny ones. Also, unless the hub is at least 10 meters (or 30') higher than the surrounding terrain (upwind of your rig), the output of the machine will be minimal and sporadic. Towers are THE big problem with all wind turbines, but especially small ones, because of the costs and installation requirements. It was this way when I got in the business 36 years ago, and it remains that way today.

The best option for most RVers, IMHO, is PV and a decent battery bank to store the energy. I use portable panels because it allows us to have solar input while having the RV parked in the shade, I do have concerns about havening them ripped off while out hiking, but we mainly stay in State and Federal Parks, so the security is pretty good. 

I hope this discussion takes off again as it's my main area of expertise.

Matt

[Ralph Javins]

Good morning, Matthew Tritt; 

Welcome to the group, sir. 

I do not know how far back you have been reading in this thread.  I also started in solar photovoltaic panels a while back.  Literally, I built my first one in February of 1962 using 10mm by 20mm monocrystaline solar cells that we bought from Hoffman Semiconductors for a little over $11.00 each back then.  We were making our own panels at that time because we could not find an extension cord long enough to power our equipment for more than just two or three orbits, and then we ran out of wire.  

I have been operating a 100 Watt ham radio station off 180 Watts of solar panels for over 20 years on islands from the Pacific Ocean to the Pacific Northwest Region in the Puget Sound Area and up to an Island in the Beaufort Sea, Lattitude 70 North and Longitude 139 West.   I have been talking with people about solar photovoltaic panels and later wind turbines for emergency power in radio communications for a similar time period.  The basic point that I have emphasized is that they really can do this too.  It has been just in recent times with all the promotion of solar photovoltaic energy for homes that this has become a practical thing to do with the drop in solar panels and all the financial incentives there are promoting their use.  One of the best examples of how this can be done is the story about John and Carol Evans who had a 12 KW grid-tied array put on their house in Maryland.  The contract cost was $56,000.  When all the rebates and other credits and incentives had been applied, that cost dropped to $12,000.  That is a price of $1.00 per Watt, INSTALLED!   I don't think that you can find a much more positive recommendation for solar power today. 

Matt, I actually agree with you about wind energy.  Yes, I do have and I erect and use either a SouthWest Wind Power Air-X or an Air-Breeze on a 30 foot tall tripod and mast that is plugged into the 12 VDC electrical system of the motor home to supplement the solar panels on the roof, and I have the electronic metering systems on the solar panel output, the wind turbine output, and also the main load power going out of the battery system, mainly to show people where most of the electrical power comes from.  However, I still feel that the wind turbine system is a useful addition to the solar panels, and it does work at night and during storms in the daytime.  I agree that the major cost of a good wind turbine system will be the tower, and not the wind turbine itself.  Then there is the point about having a good wind resource in the first place.  When the motor home has been shown at such places as Sol West, both in La Grande, Oregon, and earlier when it was in the valley in John Day. Oregon at the Grant County Fairgrounds, the main utility for the wind turbine was as an attractive attention getter to bring people to the display and discuss alternative energy and show how it can be used on a small scale to make life without using fossil fuels a real possibility and even practical. 

Probably the most effective part of the display of all these things was the use of the Norton "Space Blankets" turned silver side out to reflect the sunlight off the things that I did not want to have warmed in the Summer sun.  Used on the motor home and on the tops of the tents and the 10 foot by 10 foot shelter did demonstrate how effective they could be as a passive technique to control solar energy and reduce the need for such things as running the air conditioner in the motor home.   Then the Sun Oven solar cooker is a great way to show that it is not truly necessary to use propane for making coffee and cooking.  There are lots of ways to use alternative energy using products available quite reasonably today.  Probably the most impressive thing about my Sun Oven is the "lazy Susan" turntable I made with two square pieces of plywood that goes under it and allows me to turn it to track the sun while cooking during the day.  That one thing has been the main feature that most of the women seem to appreciate; not needing to pick up and turn the Sun Oven with the food in it to its new position and set it back down about once per hour. 

One consideration that I must keep in mind with my motor home is that it does have a finite limit to its weight bearing capability.  To that end, and also to avoid making holes in the fiberglass roof of the Winnebago Elandan, the solar panels I have on mine are some that were made by SoloPower a few years back, and they are built in thin stainless steel sheet metal, so they are very light weight and very thin.  It is also a "24 VDC" system.  Well, actually a 34 VDC system for less IR loss in the wiring getting across the roof and down inside the motor home to the MPPT charge controller.  They do not have an aluminum frame around them which should be bolted to another framework mounted on the roof to hold them securely in place.  In fact, I literally glued them to the fiberglass roof of the motor home using sealant.  There is virtually no wind resistance to them, being less than 1/16th of an inch thick.  The main drawbacks are the flat mounting of the panels and the lack of cooling air behind them.  All of this is in recognition of the many different factors that can go into the decision of what kind of panels to use on a motor home and how to mount them with consideration to the point that it is a motor home, and the watertight integrity of the roof is a factor, along with the weight and other factors.  As you are aware, all of this is an engineering compromise taking into consideration all of these factors, and trying to do it with the fewest negative consequences.  The main thing is that I do have enough solar power to to run the radios and keep the batteries happy, along with the other improvements such as the conversion to LED lighting inside to drop the load off the batteries to a notably lower level.  No, I am not trying to run an air conditioner off solar power. 

Anyway, I think that there are many things that we can discuss, and, if you do not mind, as I am writing this thing, perhaps you could also review and critique what is being written for fact checking with current thinking and other suggestions.  I cannot claim to know everything about photovoltaic solar panels for domestic use.  My early experience was in a scientific application  Most of what I have done, as you can tell, is with smaller systems for portable and mobile applications in remote settings. 

Enjoy; 

Ralph 

Latté Land, Washington