(un) Common Sense and solar Questions

[McDave]

This should be a no brainer for experienced RVer's. What orientation would you prefer to park your RV as it relates to the summer sun? N,S, or E,W. Taking into consideration awning on right side (passenger). The goal is to avoid the most intense heat, both inside and out. This would fall under passive solar? For active solar collecting, does it matter if the panels are aligned lengthwise N/S or E/W? I would guess it would be more critical at other times of the year. The reason I ask is if planning a solar system, which direction would you prefer to mount the panels on the roof once you have determined the preferred orientation of the RV? Do all of these considerations change in winter when you are trying to get as much passive solar exposure as possible?

I have done some calculating and have determined my approx. daily usage to be 50ah/day or 600wt hr/day. I would like to have at least 2 days autonomy. Could a 200 watt system with 200ah of battery storage accomplish this, while not drawing batteries down past 50%?

My planned solar system at this point includes:
(2) 100 wt monocrystaline panels
(1) MPPT charge controller
(2) 100 ah deep cell 12v batteries OR
(2) 200 ah 6v deep cell batteries, space and cost may determine this
Assorted meters and fuses etc.

All lighting will be LED. The high amp items are pump @ 4 amps, but only used in short bursts when pressure falls below 50psi, and 12volt refrig. @ 3.5-4 amps, but it does not run constantly, maybe 50%? And a bathroom fan/ light/ vent combo @1.6 amps, also used in short bursts when steam or other "gasses" may be present.
All other appliances, heaters, A/C, etc. will be LP or 120v, as I have a WFCO8955 power center and a generator. Trailer is well insulated at R7.5+ walls and R15+ ceiling, roof is painted with Henry reflective paint.
This is a "Toy Hauler" that will mostly be used by 1 person, but occasionally 2 for motorcycle rallies of 3-4 day duration.

Any answers, comments or suggestions are most appreciated.
Thanks in advance,

McDave

[hankaye]

McDave, Howdy;

As one who lives in an RV I'll say this simply as I can. There is NO rhyme nor reason to the way that campsites
are placed on the face of this Earth. Nor is the amount of space that you may ... or may not find to maneuver
to place your Ct with tow vehicle with the panels in their bestest orientation. Finding a "Perfect" campsite is
at best, a crap shoot. My recommendation would be to maximize there placement on your roof, use attaching
points that will allow you to tip or tilt the panels to be able to grab as much energy as they can. To quote Mr.
F. Gump, "Life is like a box of chocolates, ... never know what you're gonna get." So, make some lemonade and
get what sunshine you can where you can find it.


hank

[EZDog]

I usually setup a trailer with both attached and detached Solar panels as I never want to park in direct sun no matter how badly I need power.
I will often put an Easy Up over the entire trailer if possible too and this provides the bast shade that I can usually find and really helps keep things cool with the sun off the trailer roof entirely.

I have a little pigtail adapter that I use to "Aim" the detached panels that simply puts a DMM in the circuit with the controller at the back of the panel and I can easily just watch the voltage change as I move the panel,not Rocket Surgery and does the job every time……until the sun moves of course!
I carry a cheap meter with every panel and koine are mounted on simple stands making for easy aiming too.
I will tether the panels to the trailer or something closer that is immovable with heavy steel cables that would be tough to cut quickly without the correct tools and so far I have had no trouble anyway.

So like said above I stick the trailer where they tell me too and try to make the best of it.

[Shadow Catcher]

Our 66 cell (high voltage) 185W panel covers the better part of half the tear, its solar mounts lift it enough off the tear to provide some shade. The High voltage means it puts out useful current from sun up to sun down and in shade.

[SalsaDog]

I built a similar solar system for our ct. It worked well until late fall through early spring. Here in NE Wisconsin, we have a
lot of overcast days during that time and snow/ice. At first I had one panel mounted on the roof and one I could connect
to a shore power socket for "remote" locations when we set up under trees or in a campground. Futzing with that got old
fast. I mounted the remote panel and a third panel on the roof, which provided enough potential for the overcast days
when we camp in the cold months. The third panel is not needed when we camp in the west.

Next I purchased a 40 watt panel and set that vertically and connect it to the shore power socket. That maintains the
batteries when we are not using the CT and when their is snow and ice. I'm not going up and cleaning/scraping panels
in the winter. For us, our two T105s rarely fall below ~90% on a daily basis and have never been below 82%.

Components: 3) 100 watt panels, 4 gauge wire, Propex furnace (1.6 ah), Engel12v fridge (2.2 ah), Sure SIne 300 inverter,
led lights, Fantastic fan and Trimetric controller and manager.

The only glitch I had was the Propex furnace would through an error code if system voltage is >= 15. I set max charge volts
at 15.4. The T105s should see 15.6 volts, but the inverter needs <=15.5 volts. I installed a buck converter (efficient) to
limit voltage to the furnace to 13.6 volts.

I spent the month of March in the National Forests in Arizona. All system components worked without a problem. Except
the two scissor jacks on the ct which I forgot were down and I tried to drive away.

[McDave]

Alright Gentlemen, I believe we have the answered the majority of the questions.
A big thanks to Hank, for injecting some sanity and reality here. The K.I.S.S. approach (keep it stupid simple) is almost always the correct path. Having said that, it's just not in my nature to leave questions unanswered. "Knowns should be known, and unknowns should also be known. The unknowns that are unknown, can't be known, so we let them slide until they are known to be unknown." Donald Rumsfeld.

1. In the summer, in the Northern Hemisphere, with the goal of least passive solar gain for the cabin, trailer should be oriented nose North, curbside door East, awning to the East. How do I know? A Heliodon. "What's that" you say? Look it up, then the knowns will be known by you. Actually, I just improvised with an old fashioned Globe that tilts and a flashlight.
But Heliodon sounds cool!

2. Active solar gathering. The collection panels should be aligned in the East, West orientation lengthwise for maximum exposure, and the ability to tilt in 1 or 2 axis will also help efficiency. How do I know? Yep, Heliodon.

3. (un) Common Sense gleened from your anwers. Kudos to Hank, "Striving for a less complicated life since 1949 ... ". I love that kinda stuff. EZDog's simple and elegant EZ-UP solution is genius. A portable carport. SalsaDog's post was chock full of useful information and real world data. I'll be using ALL of that as knowns. Also, remember to retract those leveling jacks!

So, I feel like we learned something here. Thank you all, good stuff.

McDave

[hankaye]

McDave, Howdy;

Not to often I get such favorable reviews

Like that you went and did the improvised Heliodon, neat things.
Were yo able to accurately follow the path of the Analemma on the Globe?
Generally found in the South Pacific Ocean off the coast of S. America along
the Equator.

The reason I have my signature is to remind ME to not over-think things as generally
the answer is right in front of me ... all I have to do is open my eyes and see the danged thing.

hank

PS. for those of you that want to know what an Analemma is;
https://en.wikipedia.org/wiki/Analemma

[McDave]

Hey Hank,
I cant say "I accurately followed the path of Analemma", this globe is so old Oklahoma is marked as "Indian Territory". But it does have the Tropics of Cancer and Capricorn denoted. It's funny how we haven't used globes in many decades. Most people had one in their home, and now just us old timers and low tech types that still have them, right next to the Encyclopedia Britannica and the Funk and Wangles circa 1965. Still, its nice to have all that info, safe and warm in the "Study". I'll bet I haven't walked in there 5 times in the last 10 years, VERY nostalgic.
The whole "Life less complicated" thing also reminds me of what you really need. Dad would say something like " 3 squares and a warm place to sh**". He spoke in riddles that took me 25 years to understand. You couldn't get a straight answer out of the man. He wanted you to learn for yourself. I swear, I thought he was a retard when I was a teen, but the older I get, the smarter he gets!

But, if you have the basic fundamentals, you can figure the rest out.

McDave

P.S. @ Hank,
I know I have mentioned Chope's in La Mesa, and the times we had in 70's, when the West was still wild. Well, I ran across this site. The Chope's post was cool, but the website is very interesting. I thought you might like it. Made me a little homesick. http://www.newmexicobackroads.com/2009/ ... sa-nm.html
The "Land of Enchantment" really is a great place to be, or be from.

McDave

[hankaye]

McDave, Howdy;

Sounds like the places I used to hang-out in when I was younger, more resilient,
and before I actually learned to give a rat's furry butt about anything. I still have
a "moment" ever-onct-in-a-whiles ... but that just a bit far to travel for a "Floor-show" .

hank

[McDave]

Hey Hank,
I agree. The "Glory Days" have come and gone for me, and Chope's as well. I'm not sure there is anything special about it anymore, other than the legend. At the time it was more of a hideout, middle of nowhere place. Like everything else, it only mattered if you were actually there.
My point to the link was the backroads site and the endeavor this guy is involved in. There is a lot of history in that area.
New Mexico still has a lot of wide open spaces and some of the most diverse landscapes and ecology and weather to be found. I been a lot of places, but it is still rare to see a sunset like you can see in the high desert. Before cable and internet and malls, outside is what we did.
That's all.

McDave