A cat among the pigeons, a can of worms? Interesting discussion?

Warren-Pat_01 · Guru

A cat among the pigeons, a can of worms? Interesting discussion?

Meredith · Senior Member

The main thing I like about the 2 permanently mounted panels on our roof compared to the 1 portable panel we also carry is its convenience. Its always on, no worries about doing anything to it, pull up and make a cuppa and the rooftop solar is already working. If I want to worry about optimising power I can get out the portable panel and set it at the best angle and direction, but a lot of the time we don't bother as we rarely need the extra power. Sure the rooftop panels may not produce as much as they might under the best conditions, but they produce enough that I don't care! What you are suggesting just sounds like too much work for me.

denmonkey · Senior Member

what she said :)

I've gone with panels that are large enough to make up for the flat mounting deficiencies, that it does not matter for my intended purpose.
Sometimes I think it is just easier to go with an additional panel than come up with a workable solution for angling panels.
Plus consideration obviously has to be given to where the vehicle is parked with regards to the suns movement.
Not really a concern with flat panels if you're happy with their output.

I've also gone away from portable panels as I don't like having to allow space for their storage when in transit or packing them up when away from camp.
For me vanning is about the simplicity of hooking up and going and pulling up and relaxing.
The less set up the better for me and portable panels don't fit into that equation.
Plus I've set myself up where my draw on my batteries is minimal and efficient. I don't expect the comforts of home to be available to me when I'm away.
But that's all my mileage biggrin

dabbler · Guru

My goal is to end the day with full batteries. If I can achieve that with my inherently, insufficient, flat mounted panels without dragging out my larger folding panel then I'm happy.

Ron-D · Guru

Your a bunch of lazy old old sods putting out a set of panels only takes minutes biggrin

Jaahn · Guru

Hi smile

I would say, depending on where you are, you could get allmost double the power over a full long day with chasing the sun using portable panels.

I do not choose to do that now.

Jaahn

T1 Terry · Guru

My take is that a roof mounted system should be enough to do the job when the solar is average to good and portables come into play when the solar is or has been poor for a number of days and you need to get the batteries back up quick.
Portables also work great for those with a limited roof area, like in a smaller rig, but still want to use a reasonable amount of power without the need for a generator. Let's face it, if we are free camped we are not likely to go off site seeing while the generator is sitting out in the open so that kills the argument about having to stay close by to stop your portable panels becoming someone else's portable panels before you return. Panels are so cheap these days I doubt the value is still there to go out of the way to steal portable solar panels, so a length of stainless cable anchoring the whole lot back to the RV with padlocks to link the strings together would stop the opportune thief, a generator is whole different story.

T1 Terry

Warren-Pat_01 · Guru

Just coming back in - thanks for the comments so far, people.

Two problems I have -
1. Having a pop-top van. Adding weight to the roof means I have to lift that too! And being quite tall, it means that I have to bend my 70+ year old back to get the maximum leverage on the lifters. Sure I could add those blow-up tubes (E-rectus, etc) but they aren't cheap!

2. Living in "glorious" North Qld where on our way south three months ago, we saw only two vans going against the flow of everyone heading north - us & someone else! Most were Victorians but there were a number from other states as well, all heading north (yes, it was VERY cold in Warrnambool but new grand children called us).

But we don't see too many southerners in NQ after September, October, November because they think it's too hot, too humid. So when we go camping/bird watching at this time of the year, the last place we need to park is out in the sun - so for me, portables are the better option. Mostly I shift the panels twice a day to get maximum power into the battery.
Security is an issue but I've seen there are some scary options available (thanks to other members) to prevent this.

Jaahn · Guru

Hi Warren smile

Not sure what you are getting at but here is my take on your investigations.

" it gave an output of just over 3.2A. Testing it while it's mounted on the roof (flat with an air gap), it gives 2.2A which is just a bit down but a loss" that is down to only <70% output. Indeed I have observed that in hot sun condition the increased cooling from being tilted gives better performance also than flat as the panel stays cooler over time.

I had a MH which had a rubber membrane roof which I choose to not ruin by mounting panel on it etc. I had a good 'gear box' on the back and selected panels which fitted nicely on top of that in a stack of 4 strapped on. Worked out well and easy enough to do and set up two or 4 depending(24V) on need. I had a SS rigging cable made up with eyes at each end, long, and slotted the panel rails to slip it through them. So the panels were secured at all times on the back or on the ground with a lock. Good enough for casual thieves. furious

Now I do not currently use portable panels but use less power and have mounted panels permanently on my newer MH roof. It has less storage room too. I have some bigger panels to put there but it is not desperate so they are still in the shed I have a VSR so arrive fully charged. If the solar is not enough I give the engine a run.

Jaahn

swamp · Senior Member

HI
Panel angle and direction
effected by seasonal & longitude
Both of these influence greatly power production and donot forget northern summer heating of panels

There are many online angle calculators that take into both of above .

Just allow for roof top setup to be around 30% oversize due to the AH production not being as efficient .
If maxed out for realestate add a MPPT controller as well is always a good idea.

solarelectricityhandbook.com/solar-angle-calculator.html

https://www.solarquotes.com.au/panels/direction/

-- Edited by swamp on Sunday 26th of August 2018 10:45:23 AM

-- Edited by swamp on Sunday 26th of August 2018 10:49:36 AM

-- Edited by swamp on Sunday 26th of August 2018 10:58:05 AM

Warren-Pat_01 · Guru

Hello everyone,
I guess my initial query when I started this post was to find out why so many members insisted on taking on the local power companies with x number of 100 to 300w panels on their vans, motor homes & whether they were aware that flat mounted panels weren't as efficient as those placed on an angle.

I'm very much aware that some of you are permanently on the road, living independently as much as possible & have greater power loads than I do with a few LED lights & a 12v TV. I also acknowledge that in the North Qld area we get more solar than others who dislike our climate & who choose to live "South of the Border" which in NQ statements, is south of Rockhampton! I know my solar on my house (a 2kW system) produces as much, sometimes more than my brother's 5kW system (between Wodonga & Wangaratta).

And having the panels on the roof as some of you have pointed out is the best way of keeping light fingered people away from "borrowing" your equipment. During the 90s there were quite a few thieves intent on borrowing some of Telstra's remote equipment - only one item was not recovered from our area & that was a generator from an optic repeater about 430kms west of Townsville. Another generator was "borrowed" from a very remote radio site - the fishos involved were silly in that they broke into the site (it was alarmed) & made some "free" phone calls that were traced. Another time a remote site was being "prepared" for a late night hoist of all of its solar panels - the "borrowers' were unfortunate as they were seen & the panels had alarms on them. Cutting a longer story short, a cannabis plantation at Lightning Ridge didn't get the power that was expected!

So thanks to everyone who chose to answer my perhaps sarcastic sounding title.

I have discovered that my el-cheapo controller has taken the count & I'll be investing in a better one next week - hopefully we'll get home before it does.

Happy safe travelling.

T1 Terry · Guru

I looked at building remote power units built in/on a shipping container with a solar tracking 10kW array that folded down on each side of the container in high wind and each night to avoid the dust build up from the dew glueing the dust to the panels. Might still do it but the demand for off grid house installations along with RV installations has eaten up any spare time I once had so it remains on the back burner.
There are a few members of the private lithium forum that have developed solar tracking panels for their house installs using the now abandoned giant satellite dish framework and either 2 plane or 4 plane tracking. Seem to work well enough and certainly increase the daily solar harvest

T1 Terry

oldtrack123 · Guru

I can assure you there are definite advantages with tracking the sun, if you have limited space for panels & portables are not a real option

That was my situation with our motor home[winnebago Lawson]

I built a simple roof mounted tilt & rotate frame for the panels .

Usually changed position twice & sometimes 3times per day

The ammeter reading differences was quite impressive

As we travelled widely both north & south /winter & summer,[ Far north Queensland & NT _ NSW ,Vic & SA]

It had the advantage that I could set them to optimum position no matter where we were

Did not have to worry about some stealing portables during the day ,especially when we went for a long time, on long walks or fishing

-- Edited by oldtrack123 on Thursday 30th of August 2018 07:28:19 PM

T1 Terry · Guru

Hi Peter, haven't seen you here for a while. About the only down side with roof mounted solar tracking is the lock down catches either failing or them being missed in the pack up to travel again regime and I'm sure we have all been guilty of at least one error during this stressful period :lol: We have left steps all over the country as well as shoe cleaning mats so we are just as good at the "bugga" factor as anyone.
When we were doing the rally circuit and we mentioned our intention of building a solar tracking system or panels that could be lifted in a multitude of different direction while still attached to the motorhome, the common response was "Been there, done that, have the destroyed panels to prove it"
Our solar array does tilt from the rear or front and was designed that way for easy access to the underside of the panels. We have only had to use it once for improved solar harvest and that was recently in May at Taggerty in the Vic highlands. We arrived with flat batteries due to an alternator failure combined with multiple days/nights driving in the rain. It did get us through the 3 day week end and recharged the battery enough to restart the diesel engine (we only have the one battery pack) so it was good to have. We also had a failure of the same set up after a bolt rattled its way out while traveling across to WA. Fortunately we were close to our destination so we crawled along in the rain and dark till we reach a safe haven where I could fix the problem so no serious damage occurred. It would have been a different story if we had been traveling with a caravan rather than a motorhome because we would not have had the knocking on the roof to signal there was a problem.

T1 Terry

oldtrack123 · Guru

Hi Terry

Yes ,I agree biggrin

There can be some of those problems you have mentioned ,but with many years of use [a lot travelling over pretty rough ground ] had no such problems..

Perhaps because I did not rely on catches to hold down when travelling.

One concern was strong winds building up while the panels were up & we were away from the MH. [ not that the panels would be damaged ,more about how the MH could be buffeted]

Note, the extra weight of the set up was negligible ,all aluminium & mostly MIG welded, by an expert in that field[me]

Reed · Senior Member

We spend summers in Rocky Mountains at 8000 to 10,000'. Solar angle is fairly vertical and there is no need for tilting. We commonly get 1400 W to MTTP controller.

We spend winters in Yucatan which is about 20 degrees north. Solar angle is about 30 degrees from vertical in winter. Cosine of 30 degrees is about 0.87, so we get about 87% of maximum or around 1100 W to MTTP.

At age 78, I have no great desire to get on roof and set up panels.

Our Roadtrek has but 415 W of solar and that has proven quite sufficient last two winters in Yucatan. Turn absorption refrigerator to propane at night.

Reed and Elaine

Ron-D · Guru

Reed wrote:
We spend summers in Rocky Mountains at 8000 to 10,000'. Solar angle is fairly vertical and there is no need for tilting. We commonly get 1400 W to MTTP controller.

We spend winters in Yucatan which is about 20 degrees north. Solar angle is about 30 degrees from vertical in winter. Cosine of 30 degrees is about 0.87, so we get about 87% of maximum or around 1100 W to MTTP.

At age 78, I have no great desire to get on roof and set up panels.

Our Roadtrek has but 415 W of solar and that has proven quite sufficient last two winters in Yucatan. Turn absorption refrigerator to propane at night.

Reed and Elaine

Hi Reed none of my business just curious are you an American citizen ...

Reed · Senior Member

We are Americans. Australian caravaners are far more innovative in solar and LFP usage than Yanks which is why we spend time on This forum. There is much to learn.We primarily boondock in Rocky Mountain West and moochdock (set up on our sons properties) where most Yanks only go to RV parks while it seems most Aussies free camp. Again, there is a lot for us to learn even after 10 years of traveling.
Reed and Elaine

Ron-D · Guru

Thanks for your reply Reed glad you enjoy the forum....

Warren-Pat_01 · Guru

Hello Reed & Elaine,
I took the liberty in checking you out - you're certainly not a beginner on this forum. I trust someone gave you a warm Aussie welcome.

I'm certain that we can learn something from you of your experiences as you are learning of ours, even if it's just travelling to the USA &/or Canada. Our son spent some time in Ottawa (daughter was in England) so we took the opportunity to visit for a Fall (that included a bus tour through the Canadian Rockies) & a Christmas (very nice but a bit chilly too).
The latter reminded me of the Disney comics that I read as a child of Donald Duck & his nephews shovelling snow! Fortunately our Federal Govt gave my son a heated apartment, garage & sidewalk (footpath) in the middle of Ottawa.

We noted that English people went to caravan parks (just down the road) where they were expected to be entertained. We generally use caravan parks that have no entertainment, no jumping castles, etc.

Reed · Senior Member

Warren - North America offers a lot of places to visit from Belize through Mexico, USA, and Canada. Most of summer travel is in Mountain West. Free Camping can be found on most Federal land. Summers are cool above 2500 m. Being solar autonomous means no firing up a generator and frightening wildlife. We have had Bull Moose fighting within 25 m of fifth wheel, Coyotes wander beneath the trailer, Elk and Deer wander past, and may have a dozen hummingbirds of four species at our feeders. Solar is quite delightful to have

Alas, our brag about not using caravan parks is about to end. We are supporting the daughter of our best friends (and our daughters best friend) in her run for US Congress. She does play rugby.

Reed and Elaine

KJB · Guru

Which ever way you choose to do it ,country USA/Canada is a magnificant,scenic place to travel. Safe , welcoming people ,inexpensive and easy with something to see and experience no matter which way you turn. Great countries.

Aus-Kiwi · Guru

What ever works ! I have two seperate solar 6.5 kw systems on my home . One has half the panels facing west . Up to about 1am the system With half west panels Id nearly half the system facing north . But the west facing goes a little longer in the afternoon . I guess this applies to caravans etc too ? With fixed system on our motorhome we find in most cases its on Full charge by 10 -11am . Depending on load usage . When we had folding panels . It didnt take long before the panels were not in direct sun., Atleast roof mounted works all the time, theft and damage is not an issue . I have seen some run over , must say it looked on purpose too ?? The new lighter flexable panels may be an option with lift top ? Or both ?

Reed · Senior Member

KJB

Diesel Fuel in US hovers around $3 US/gallon. It is well over a dollar US more in Canada and close to a dollar more in Mexico. The Mexican government supposedly subsidized fuel until a few years ago.

Very rainy for several days in mountains of northern NM. I believe we got close to 5 cm of rain. This is great for the forests and for reduced forest fire danger but not great for solar. We are down 2 kW-hrs but still have over 5 kW-hrs available but will turn off inverter when not in use.