TerraLiner:12 m Globally Mobile Beach House/Class-A Crossover w 6x6 Hybrid Drivetrain

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16. The TerraLiner Supplementary Generator: Summary


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In summary, for those of you who were hoping that the TerraLiner could completely eliminate a supplementary, diesel generator from the equation, well, that seems very unlikely to happen.

After all, why does Next Generation Engineering advertise on its website that its small generator engines will save truckers thousands of dollars per annum, because instead of idling their truck's big engine, they'll just run a small gen-set instead – see http://www.nextgenerationpower.com/semigenapu.html . Granted, that's not quite what we're talking about in the TerraLiner's case, because the Jenoptik would not be running constantly in idle. Rather, it would run in “bursts” to top up the batteries. And yet, even still, it seems that a small, very compact 7 – 15 KW generator that weighs somewhere between 200 to 300 kg might prove much more efficient than running the Jenoptik periodically. It would also be much easier on the batteries. A small generator seems to be the ultimate solution to any worries that “There won't be enough solar power!!” to keep all TerraLiner systems running, when the vehicle is boondocking.

I could be wrong about this. I am not an automotive engineer, and this sounds like an issue Haf-E might provide some insight into.

But the larger point still stands. It's best not to get too worked up about solar. I view the solar panels that the TerraLiner will carry as a mere supplement to diesel, not as a complete replacement for diesel, not even when stationary. The TerraLiner will still have a 1500 Liter diesel fuel tank, the maximum size allowed. So the TerraLiner will have lots of diesel fuel available to run a small generator, one that should more than make up for any shortage of solar power. A small generator of the kind just described does seem the best solution to the problem of the TerraLiner not getting enough power from the solar cell array, in certain climates, when running all energy-intensive systems at maximum.



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PART Ia: SOLAR ENERGY – Solar Power Technology


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1. The Solar Array on the TerraLiner's roof: what full coverage means


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So with all of those caveats in place…… here are my current thoughts about Solar.

First off, if you do a Google search for “Motorhome + RV + Massive Solar Roof”, not that much comes up. Indeed, one image that seems to come up consistently using various word combinations, is egn's Blue Thunder:


1 image


There are simply not that many examples on the web of motorhomes that have this degree of Solar Coverage on the roof: where literally every square cm of possible space is covered with solar cells. Here are few more ambitious examples.

The first is a motorhome in Australia, which achieved more or less maximum coverage, with no less than 32 (yes, that's right, thirty-two) mono-crystalline panels of 40 KW each, for 1280 W in total:


10 images


See http://robbiebago.blogspot.com.au/2013/08/installing-solar-panels-on-our-rv.html .

Their reasons for going with many more smaller panels instead of just a few larger ones are interesting, and worth quoting:


QUOTE

Small solar panels v larger units

We decided to purchase small panels and join them together for 2 main reasons:

1. We can achieve better roof coverage with smaller panels (roof area is valuable real estate so we want to use as much as possible)

2. We will not lose as much solar input if some shade were to fall on even part of a panel. Research taught us that smaller panels are more efficient in partial shady conditions. For example, if the shade of an antenna falls across a panel, then that panel's maximum input is reduced by half. So if we have one 120 watts panel and some shade falls across a corner of it, then it's input is reduced by half to 60 watts. Whereas if we have three 40watt panels affected by the same shade but the shade only falls on one panel then only that panel is reduced to half, producing 20 watts and the other two panels' input is not affected thus producing 40 watts each. This way we will still be getting 100 watts in partial shade compared to the 60 if it were just the one larger panel.

UNQUOTE


This actually is a big problem with many mono-crystalline panels: when shade falls on just one solar cell in a panel, because the cells are typically wired in a series, shading effectively brings the entire panel down to the output produced by the shaded cell. The following video from PowerFilm, a maker of flexible thin-film solar cells that do not suffer the same problem, explains the consequences very clearly:


https://www.youtube.com/watch?v=flvkYi753Js


However, not all mono-crystalline panels are made equal, and some, like those made by SunPower, have been deliberately designed to continue operating at a high rate of efficiency despite shading. The following video explains why:


https://www.youtube.com/watch?v=0qVfge4J1aA



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2. To Tilt or Not to Tilt? Is Tilting the TerraLiner's Solar Array Necessary?


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The other problem is that to achieve maximum efficiency, mono-crystalline panels have to be angled as far as possible perpendicular to the sun's rays. Here is an example of a 1978 GMC motorhome restoration and conversion, with 1.1 KW of solar panels, some of which can tilt:



7 images


https://www.youtube.com/watch?v=PMwPcVjXj8E

See http://www.solarsonic.com/rebuild_solar.html and http://solar-sonic.com/rebuild_history.html .




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Here are two more examples of motorhomes with “tiltable” solar panels, albeit not complete solar coverage on the roof. Their solar coverage is more “patchy:


5 images




See http://www.technomadia.com/2015/02/the-almost-fantasy-of-solar-powered-rv-air-conditioning/ .



5 images




See http://tinyhouselistings.com/maximizing-your-solar-harnessing-power/ .




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And here is a really wild, “Zombie Apocalypse” Bug-Out bus, in which the entire solar array tilts as a single, integrated unit:


2 images


https://www.youtube.com/watch?v=EvjeSXc4T1U

See http://tinyhousetalk.com/1990-off-grid-solar-bus-conversion-motorhome-for-sale/ and http://tinyhouselistings.com/bluebird-school-bus-conversion/ .

Note that despite its massive solar array, this bus still has a propane heater and stove, because, as the owner explains in the video, “it's not efficient to heat with electricity when you're using solar panels.” The video was published in 2014, so presumably it's recent, and so the view he expresses is still somewhat relevant today, in 205?

He not only does not heat with electricity, he doesn't cook with electricity either. He does have a microwave oven, however, that he states pulls about 700 W of power, and that this amounts to almost half of his total solar output. So one could guess that despite the impressive size of his solar array, his solar panels are perhaps not that efficient. This is not a 3 KW solar rooftop setup of the kind we'll see further below, nor is it a 5 KW set-up that will be possible on the roof of the TerraLiner.

It would be really great to know what everyone thinks of such “tiltable” arrays. Notice how his tiltable array has some “gaps” in it: these are clearly where the array needs to leave “space” so that it can descend over items projecting from the roof – hatches, ventilator, A/C units, etc.

Is such a huge, integrated titlable array necessary? Would more individually titlable panels be preferred? Which would make more sense from a mechanical point of view? With a single tiltable, massive, integrated array, one gets mechanical simplicity. But the panels at the trailing edge will angle upwards to a position very high off the roof of the vehicle, and the whole array will then act like a bit sail. Whereas two separate rows of panels that can tilt separately would seem a much better solution. But should each panel be able to tilt on its own, individually?

Or is titling really necessary at all? For instance, if you are reading this egn, it doesn't seem that you went for a “tiltable” array on Blue Thunder. What were your reasons?

Here is a an excellent, clear video that speaks directly to the question of tiltability. It insists that during the winter months in Arizona, tilting panels adds another 37 % energy to the system. Tilting three solar panels is like adding a fourth, in terms of the energy boost provided:


https://www.youtube.com/watch?v=dP_8i7nbBcE



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3. A Few More Examples of “Total Coverage” Solar Roofs


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Here is an interesting build-up sequence, composed of different sized panels to achieve maximum coverage. With 10 modules, this German motorhome achieves a maximum potential of 760 KW, on a vehicle that is 7.39 m long x 2.30 m wide:


7 images


See

http://www.unki2010.de/page5.htm , http://www.unki2010.de/page5a.htm , http://www.unki2010.de/page5b.htm , http://www.unki2010.de/page6.htm , http://www.unki2010.de/page6a.htm , http://www.unki2010.de/page7.htm , http://www.unki2010.de/page8.htm , and http://www.unki2010.de/page9.htm .



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The owners seem to have multiple motorhomes for different types of adventure, and seem fond of winter camping: http://ski-web24.de/Privat/frame.htm , http://www.unki2010.de/index.htm , http://ski-web24.de/framewomo.htm , http://www.unki2010.de , http://www.unki2010.de/page1.htm , http://www.unki2010.de/page2.htm , http://www.unki2010.de/page3.htm , http://www.unki2010.de/page4.htm , etc.

They even tested their solar set-up in winter, although as one might expect, they had to cover the windows with thermal insulating mats (or shades, or blinds, or screens, or whatever one wants to call them…..):


6 images


Here is an Australian Fuso conversion, that also achieves near-maximum coverage. It's also interesting because it appears to be towing a “toy trailer”:

4 images



See http://www.salesandauctions.com.au/...torhomes-for-sale-QLD-Fuso-Bus-Motorhome.html .





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It's also worth noting that the Shachagra has 10 Kyocera 210 KW panels, for a total power output of 2100 KW (36 seconds into the video) -- see Expo reference:


6 images



So too, Rob Gray's Wothahellizat Mark 1 had 8 solar panels -- see http://robgray.com/graynomad/wothahellizat/wot1/diaries/diary_30/index.php , http://robgray.com/graynomad/wothahellizat/wot1/diaries/diary_31/index.php , and http://robgray.com/graynomad/wothahellizat/wot1/diaries/diary_32/index.php :


3 images


There's also this interesting.....


The long truck....


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Last but not least, here is a Mistubishi box truck, formerly a 35 foot U-Haul moving truck, that an Israeli man converted with maximum solar coverage on the roof, reminiscent of egn's Blue Thunder:



9 images






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4. Full-Roof-Coverage Solar Arrays are not that Common


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But aside from these examples, there's not much else on the web. In most images of the roofs of motorhomes using solar, at best the coverage tends to be only partial – see for instance http://www.rvtechmag.com/electrical/chapter11.php , http://blog.conrad-anderson.co.uk/?cat=12 , http://marciasrvtravels.blogspot.it/2014_03_01_archive.html , http://jimthetruck.blogspot.it/2012/10/roof-rack.html , http://www.chriswrightmotorhomes.com.au/cd0ea7ab-4d12-4ba7-a398-9f0100648dbe.html , http://tinyhouselistings.com/23-gmc-solar-motorhome/ , http://www.caravanningaroundaustralia.com , http://vogeltalksrving.com/2014/01/roadtrek-introduces-new-eco-friendly-motorhome/ , http://www.chriswrightmotorhomes.com.au/page1001.html , http://www.promobil.de/forum/threads/35193-Richtiger-Solarregler-gesucht , and https://barbrvsales.wordpress.com/tag/rv-solar-panels/ :


9 images






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5. The Design Implications for the TerraLiner's Roof


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The reason why full-coverage solar arrays are not that common is simple enough: the roof is also real-estate where motorhome designers and do-it-yourself convertors have wanted locate hatches, ventilators, satellite dishes, and A/C units:

1 image

6 images


In most of these examples solar cells on the roof were an “afterthought”, fitted only after a motorhome was designed, built, and sold.

But even a manufacturer as deeply committed to solar as EarthRoamer, until very recently still did not completely cover the roofs of its vehicles with solar panels – see http://earthroamer.com/xv-lt/systems/solar-power/ ,http://www.expeditionportal.com/for...oamer-the-built-in-the-USA-Expedition-Vehicle :


3 images







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But in its most recent and largest vehicle, the XV-HD, Earthroamer now seems to be designing the roof with maximum solar coverage in mind -- see http://www.gizmag.com/earthroamer-xv-hd/37636/ , http://www.gizmag.com/earthroamer-xv-hd/37636/pictures ,


6 images




Even still, let's just say that egn's Blue Thunder is rather atypical in this regard…. emoticon Blue Thunder's roof is unusually well-covered with solar.

I then want to emphasize that the kind of solar coverage specified in this thread will be rather “extreme”. It will not be typical at all, in light of the wealth of examples provided above. No doubt because until recently, very few motorhomes were deliberately designed with solar in mind.

By now it should also be clear: in order for a vehicle to have truly “full coverage” of its roof with solar panels, a great deal of anticipatory design thinking needs to be done. For instance, if the A/C units can be placed anywhere else other than the roof, they should be. Ventilators should be designed so that their tops are flat and can also be covered with smaller-sized solar panels. Hatches should be designed the same. Skylights may want to have “retractable” opaque covers that would also be covered with solar panels, most probably thin-film, so that they add only minimal thickness. And so on.


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6. Bliss Mobil: Maximizing Solar Coverage


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BlissMobil deserves mentioning here, because after having seen all the images above, the degree to which BlissMobil's various models have roofs covered by solar will seem quite exceptional. They were clearly designed from the very beginning to maximize roof-surface devoted to solar:


9 images





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From the very largest, 23-foot long modules:


2 images


To the smaller modules, it's clear that BlissMobil is unusually “committed” to solar:


5 images



See http://www.blissmobil.com/en/ .

Again, I haven't seen many other vehicles that have roofs as packed with solar, apart from egn's Blue Thunder, the U-Haul Truck conversion already illustrated above, and one more vehicle that I will discuss a bit further along in the thread:


3 images



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