So I've been studying hard and fast (to the point of perhaps later doing this for a living) and the solar equipment is arriving piece by piece as we speak. I was lucky enough to come across two commercial solar panels that together produce 600 watts which is great due to the limited real estate I have up on the roof. I've also designed a custom mounting solution that I'll post once it's up as it is indeed revolutionary in concept.
One of the many problems with this old girl is the limited scope of the technology used in 1988, so with every other turn, there's something that needs upgrading and improving. The existing control panel over the entry door also included the water pump and water heater switches, but it's always extremely easy (for me anyway) to forget the water pump and the coach sit for weeks draining the battery. So this upgrade also includes measures that address my forgetfulness as well as bring the whole coach's electrical system into today's efficiency.
As it already is, I have cameras all over this thing, and at the entry door there's a monitor that gives you an idea of what's happening outside the door. The old Holiday Rambler switches that control the porch light, cabin light and power step are to be partially relocated to the new control panel that's to be mounted in the wall alongside the CCTV monitor.
Upon demolition of these kinds of projects, you really get a good idea of what the real workmanship is just under the surface. As good as HR was in engineering, there did have jackals on the assembly line where I constantly find terrible workmanship in many facets of the wiring and penetrations between panels and things of that nature. Also, on this particular project I came to realize the new control panel was in no way going to work mounted to a 1" wall, I needed at least three inches depth.
Fortunately, the closet is right behind the wall and the upper shelf is the ideal height to mount an electrical junction box behind, and then use it to do all the electrical connections needed to power and control what is now the Ceiling lights, Porch Lights, Water pump, Water Heaters, LEDs over the sink and stove, as well as power the Solar Panel tilt mechanisms, the four electrical monitoring readouts, time limiter relays for the water pump and water heater and a partridge in the pear tree. The power step switch is to remain down in its original location by the door. All else is being re-routed up to the new control panel, so there's a lot of wiring to do to get there.
I'll update as it goes, I hope to have the wall closed back up and complete by this time next week. This is going to make a huge difference in that area of the coach. Both walls right inside the door had veneer peal and the old magazine rack is also suffering a whole lot of ugly, so this entire spot is going to be renovated as well as adding new lighting in this alcove and extra stereo speakers in the ceiling.
I welcome any questions anyone may have on solar, I'm aiming to have this coach pretty much self-sufficient in any boon-docking situation. It's of course going to be tied into the battery system and keep it all fresh, but will also have a heavy inverter to run the AC systems as well without worry. I'm currently under study for it to even run the 30amp aspects of the Air Conditioning. I'm hearing that it can be done with just the right equipment, but I'm not there yet on the full comprehension, but will be some time real soon.
I will be following along closely on this but I am really curious how you are going to get roughly 4000 watts of solar on there to get your 30 amps for the AC. I am not an electrical engineer so I am just going by Ohms law for that assumption. 30 amps should run the whole rig, not just the AC.
You need to get together with Ralph Javins, He is quite knowledgeable on solar and power requirements.
Here is a link to the article by Ralph.
WOW, I am an Electrical Engineer and can only say GOOD LUCK powering a typical RV Roof Top AC very long using Solar, Battery and Inverter power. I have 400 watts of solar panels and four golf cart batteries which can store 460 Amp Hours of energy and LED lights and I can be total self sustained running lights and vent fans and water pump and cell phone and laptop chargers indefinitely (unless it rained days straight and no sun) BUT I CANT RUN AC'S OR MICROWAVES OR TOASTERS OR HAIR DRYERS ON AND ON AND ON..........
1) First of all, a typical RV rooftop AC may RUN on lets use 12 amps @ 120 Volts = 1440 Watts, HOWEVER it can draw maybe 4 to 6 times that much current during initial start up so its NOT just run amps, its starting surge that matters so be sure the Inverter has sufficient surge capacity TO START the AC. A 4000 Watt may well have enough surge capacity to do that, I cant say from here.
2) BATTERY ENERGY STORAGE CAPACITY: Okay to power the AC drawing 12 amps at 120 volts REQUIRES SOMETHING LIKE 120 AMPS being drawn out of your 12 Volt batteries. Lets say you're like me and had Four True Deep Cycle 6 Volt Golf Cart Batteries in series parallel with 460 Amp Hours of stored energy capacity (you may have more then my four batteries or less then four???). Its NOT good to discharge the batteries over 50%, so at 120 amps it would be less then 2 hours (120 x 2 = 240 Amp Hours) before you ran out of stored battery energy.
3) Sure if the sun were bright and direct overhead (which is only an hour or two around 12 noon) and you had 600 watts of solar panels they can be pumping amps into your batteries that time but the AC is drawing 1440 watts SO YOU STILL CANT KEEP UP and the batteries may last longer then just two hours. YES I REALIZE THE COMPRESOR IS CYCLING AND NOT ALWAYS DRAWING THE FULL 12 AMPS but right when it start and if the RV is hot inside it will run a long time......
4) Some of the BIG BOYS who have something like 700 to 1000 solar watts and 500 or more Amp Hours of Lithium Batteries and maybe a 5000 Watt Inverter and maybe some sort of soft start up AC can run their AC for short periods, maybe a matter of a few hours, but that's about it.
5) For the average Joe with maybe 200 to 500 Solar Watts and at least 400 Amp Hours of battery capacity they (I sure can) can be self sufficient indefinitely for LED lights and water pump and vent fan or furnace and cell phones and laptops but NOT an AC, to run one of those you have to really go big time and that gets expensive.
HOWEVER I'm all for it and will help if I can and best wishes and if you have enough batteries and enough solar and plenty of sunshine and a healthy Inverter with a high surge capacity YOU CNA RUN THAT AC FOR AT LEAST SOME TIME
God Bless, John T Retired Electrical Engineer
Wow, thanks John!
What great information! I don't mean to imply that I want to run the AC all the time, but to have enough power to run it, period. The actual length of time isn't really the issue, This is a whole lot of experimentation, I have too much time on my hands I think. I've already converted to 100% LED, The design (so far) will be as follows:
2 panels on the roof that are a combined 590 watts. Cabled down straight to the battery box, first stop circuit breaker, then a MPPT Charge controller, a 4000 watt Inverter and a third position transfer switch. Four meters are going at the control panel to monitor power from the panels, battery health, battery drain, and overall load.
Then it's all about component evolution as time goes forth.
So far, this thing is essentially a money pit anyway. It's a restoration project that barely makes it anywhere; I think I've used it twice on overnight camping trips. So, for now anyway, the solar isn't a huge deal, but at some point I'd like to see it evolve into one. I do know that I want the system to be more than just a battery charger/Harbor Freight type thing. Late this year I'm converting this thing to four wheel drive, then it goes to paint. It's clearly a hobby. :-)
I really do appreciate your feedback John, there's a ton of really great information there for us all to chew on that are going this direction! Thanks so much!
Thanks for the kind words Frank and I'm glad to help what I can. With 590 Solar Watts and a 4000 Watt Inverter you're sure off to a good start. I'd suggest a Pure Sine Wave (PSW) versus a Modified Sine Wave (MSW) but they are more expensive. Similar, a so called "Smart" MPPT Solar Charge Controller with Four Stage (Bulk, Absorption, Float, Equalize) and likewise a "Smart" Four Stage Charger (versus an old stock noisy humming buzzing fixed voltage Converter/Charger) will both greatly extend your battery life and protect your huge battery investment.
GEE ITS EASY TO SPEND YOUR MONEY LOL
The next best place to put your money is more battery capacity. For what you're talking you need AT LEAST 400 AMP HOURS which can be four true deep cycle 6 volt golf cart batteries wired in series parallel. I just bought another RV I'm fixing to customize and I'm going with two 12 Volt Deep Cycle Fullriver AGM batteries so I don't need to worry with acid levels and fumes and venting requirements
Of course for a 4000 watt inverter subject to how far from batteries to Inverter, YOURE TALKIGN HUGE COPPER CABLES YOU KNOW to avoid voltage drop.
Sure its expensive, but if you travel out west and boondock on BLM or Natl Forest Camps for weeks at a time like we do, ITS WORTH EVERY PENNY IN MY OPINION.
NOTE Its NOT energy we run out of or the limiting factor for extended stay dry camping ITS FRESH WATER AND HOLDING TANK CAPACITY. I have added an extra 80 gal fresh water tank and an extra 40 gal gray tank and an extra 10 gal black tank so the wife and I can stay maybe 12 to 14 days BEFORE we have to dump and take on water.
Right on John! All the stuff is going down real close to the batteries to keep the cabling as short as possible. The only real lengths will be over to the other side to the new meters.
Updated photos. Currently I'm waiting on the new Step switch and wallpaper to get the wall put back together and trim it out. Meanwhile, the new backboard is cut to fit as well as cutting out all the slots for the various components to go there. The Roof Camera is up and running and displays the area on the rood where the solar panels will go and will provide an image of which way they're deployed tilt-wise.
* The Roof penetration is done and conduit into the junction panel in the closet behind the new ctrl pnl.
* Roof Cam in, cabled to control location AND dash monitor for last minute check before driving.
* The wiring to the old monitor panel is all relocated around the corner into the new panel location-
* The New Speakers are cut in, but not yet wired.
* And of course, the mess there on the Kitchen sink!
Wall Finished! Most of the wiring is also complete that powers all the accessories and lighting, the meters ought to be functional by next weekend.
Closeup of new control panel and meters and monitor. The monitor currently has the image from the blindspot camera/door showing, but it flips over to the roof cam also which will then show the position of the solar panels, to be certain they're down before travel. Same image will display on dash monitor.
Good morning, Frank;
Rick Faunce and John Nordhoff have already given you the basic information and limitations needed about your solar panel installation, but I must also mention that I am impressed that you are including a tilt mechanism for improving the output of your solar panels.
The work you are doing is rather extensive. So far, I have been able to do just about everything that I want with only minor modification of the existing control panel system. I have tried to maintain as much of the "period authenticity" of the motor home as I can, while also upgrading and improving things to take advantage of improvements in technology and efficiency, such as the LED lighting conversion, which also required the updating or improvement of the "RV 12 VDC power converter" up to a full true voltage regulated power supply by Progressive Dynamics (their PD-4655V) that bolted right into the same mounting space and connected with the same wiring.
I am also impressed with your choice to go through the roof to get cables and things up there. I am having sufficient difficulties now with the watertight integrity of the roof on the Winnebago Elandan. The refrigerator heat exchanger ventilation shaft is my choice for getting cables up onto the roof. Right now there are only 270 Watts of solar panels up there, but I am trying to decide if I really want to buy an additional 100 Watts of panels that will go into the remaining space that is still up there. $10.00 per Watt for those last two thin film panels is something that is an emotional stumbling block for me at this time. The panels I have already are made by SoloPower on thin stainless steel sheet metal, and they are literally glued to the roof surface. That way there are no holes in the roof to mount them, and they are very thin with no wind resistance and light weight, but I do agree that the flat mounting will affect the output over the time of the day, and there is no cooling air behind the panels. All of this is a compromise with an emphasis on the watertight integrity of the roof, and they are the lightest weight panels I could find. With the LED lighting both inside and outside, and some other energy conservation methods, the batteries will still be happy with the 270 or 370 Watts that I can fit on the roof. I would not have laid out the roof mounted accessories the way it was done, but I am dealing with what Winnebago did, and the solar panels I could buy that met the requirements.
The weight of the solar panels is significant, because the Winnebago Elandan came with a 14,840 pound GVWR, but when I weighed the motor home, I had only about 760 pounds left for two people, food, clothes, tools, radios, and the other things to be carried. I have since modified the suspension up to almost 16,000 pounds, but that is the limit of the braking system (the letter K in the fourth position of the P37 VIN), which is the next limit in the weight or load capacity of the various systems and components of the P37 motor home chassis for my vehicle.
With the solar panels and the portable wind generator with its own tripod and mast that can be plugged into the RV coach 12 VDC electrical system, I can be out there for at least two weeks before I hit the limit for my water system; both the need for more fresh water, and the need to dump the "used water," and to restock the food supplies I am the major limiting factor in determining how long I can be out there on station. With the solar panels, my radios can go much longer than I can without being resupplied.
Ralph, Latté Land, Washington
After Rereading this post on running an a/c unit off stored batteries via inverter via solar,, Thats a big wish list. The only logical way is just run your a/c off a Genset, and use your solar panels to keep batteries charged up to run lights,water pump,furnace,Tv, stereo,computers and charge your cell phone.
They also come in handy for the lighting in the hot tub and above the roof top mounted pool table.
A/C unit, as described and explained earlier DO eat up stored energy real fast and solar cannot keep up with the required demand. In Laymens terms, the a/c would kick on and by the time it actually started to cool down the interior, the unit would shut down,(if the inverter didnt shut down first). Then you looking at another few hours for the solar panels to recharge the storage batteries. F.Y.I,, you can destroy an a/c unit having TO LITTLE Voltage, same as to much voltage. Compressor motors hate being starved of the electrical juices.
If your going to a really HOT or Humid area,, rely on the genset (if shore power is unavailable) to run your a/c,, If your at a campground where the weather is tolerable,, use your solar for the nessesaties,, lights etc. Just mentioning this to save you from wiring everything in and being highly disappointed.
Been there, Done that, even have a T-shirt and coffee mug from the experience.