Gary RV Roamer said:
A lithium battery is definitely a big plus, with the lower weight and far less voltage drop-off. Takes about the same physical space, though.
As for the insulation and wall thickness, RV makers build for the volume market and most people are more impressed by the interior decor and space than the R-value. And a lower price. RV manufacturers that tried to offer more effective/efficient designs have repeatedly floundered and failed, providing an object lesson for those that remain. And for the new owners that purchased the bankrupt outfit. Your wants & needs are those of a very small portion of the buying public. I'm not saying you are incorrect, but it's a fact of life.
You are, however, missing one salient fact about any RV. The size and shape means that just about every inch of wall is an exterior wall and thus transferring heat. And even just one person breathing in a small room contributes both heat and moisture to a surprising degree. Cooling an RV is not at all like cooling a house and it typically takes at least double the btus to cool even a small area. A 30-35 ft RV typically needs 25k-30k btus to keep in the 70's inside, whereas that much a/c would probably handle 1000 sq ft of house.
The battery bank size will be determined partially by the power storage density and lithium is 2.5 times as dense as lead acid. My quick investigations would show that there will be a considerable size savings. Also, over the life of the battery, the cost for equivalent number of cycles is considerably less.... actually less than half as you can see in the chart here: http://www.technomadia.com/2011/11/lithium-update-3-lithium-battery-cost/. Remembering of course that you'll be discharging the Lithium to 20% remaining while only going to 50% with the lead acid. Add to that the low/no maintenance, no fumes/fire risk and this is certainly the way to go I think. Of course, it will all get MUCH better in 5 years if Elon Musk decides to adapt his current "Powerwall" offering to RVs
https://www.teslamotors.com/powerwall
I assumed market forces were what has shaped the current offerings, I'm just an odd duck I suppose. Luckily it would appear that there is some hope, based on the response I just received from North American, quoted for your convenience below. Thank you for the link yesterday, it appears to have been invaluable.
Coupled with the new power information, I now think it's possible to design a unit that will allow for chilling the air continuously in a segregated space for up to 12 hours at a time on battery only. One that is supplemented by solar and a generator that would allow for extended stays "unhooked" in the right conditions. This aspect of the unit would not have been in any way a deal breaker in my overall plan, but knowing it's at least possible allows me to add an dimension to things that I think will substantially enhance my quality of life for an extended period.
I'm going to look forward to seeing what North American has to say as I dig in to more details. I copy and paste his email below because it really amounts to just a short selling piece and I'm sure he won't mind. If there's an interest, I'll get his OK to share the process as we go along, but I think I've found the folks that can make what I'm looking for. Because they also do "work" trailers of various sorts, they're used to function over form and seem to be able to produce just what I'll need, at least as a base to work from. It will be interesting to see how far I'll have to go for the solar/lithium work, but maybe they can do that, too. Here's the response:
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Thank you for contacting North American Custom Built RV.
Due to the fact that about 80%of our customer base are either full or nearly full time RVers, we offer up to R-52 Insulation value in our units. A good share of our customer base live in their units and move with their work. We offer this heavy insulation package a couple different ways. 1. A true year round Winter Pack includes up to R-52 (R-14 Double insulation and then R-38 Reflectant Foil Wrap insulation), plus heated holding tanks, Fully enclosed underbelly with enclosed dump valves. The R-38 Foil Wrap was developed for NASSA to insulate the space shuttles. We have had great success with this in addition to our double fiberglass R 14 Insulation. We have a customer we built a 3 bedroom 54’ Fifth Wheel who was working in North Dakota last year on the pipeline and he as well as several others, have raved about how easily the unit heats & cools. 2. You can get this in an Al-a-cart version if you don’t want the cold weather pkg and you are only I warmer climates.
Adding Thermal insulated windows is the next key element to this equation making these unit as close to a house type insulation quality available in our industry.
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I would say having 1200 Ah of battery, 1kw of solar and a 8kw generator would put me in a position to do just about anything I want
I'll have to go with a toy hauler shell so I can convert part of the garage to be a "power room" probably, and give myself enough roof space to get most/all of the solar panels up there. I'll want to bring additional gas and water, too, I think, so a garage would be handy for that, not to mention the show junk I'll accumulate if I decide to do any performing as well as competing. Longer overall unit but still a dually 1 ton should do it, letting me have the freedom to at least "tent in" to the places I can't stay at because it will be too big.
Yes... I'm thinking this is entirely possible now. Thanks again for your help.
