Costs of Alternatives for Running Fridge - R-pod Owners Forum

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StephenH

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Joined: 29 Nov 2015
Location: Wake Forest, NC
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Topic: Costs of Alternatives for Running Fridge
Posted: 08 Sep 2018 at 7:52am

There would be the additional drag of such a wind generator mounted on the 'Pod while towing. That would increase fuel consumption so the wind energy would not be "free."

StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS

lostagain

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Posted: 08 Sep 2018 at 7:44am

I've been around the little sailboat sized wind generators and I have to say, they are in a different class than the 100m blade wind turbines that you see in the wind farms of Nebraska. They make no discernible noise at all. If the wind is blowing what little noise they make is overcome by the noise of all the boat rigging with halyards clanging on the mast, wind whistling in the rigging, and other stuff going clunk as it bounces around in the breeze. And I've never seen a dead seagull in the vicinity of a wind generator with obvious impact wounds. Not say'in it doesn't happen, just my anecdotal experience, which proves nothing.

The real problem I've found with the small boat type wind generators is that they stop generating at a max of about 40 knots or about 50 mph. If one was to be developed to use on an RV it would need to be able to work at speeds up to 70 for the vehicle plus an allowance for headwinds. That's an engineering issue that some fine engineer will solve if someone ever decides to build one. And since it doesn't have to be built, necessarily, to marine grade as would one on a boat, that gives the engineer more options on materials.

Though wind generators may not be ideal for an rPod sitting still, the original suggestion was made to give it an energy source to run the fridge while moving, a condition in which there is, by definition, always wind. And the flaw in the hypothesis is finding a device that can operate under wind conditions found while driving.

Never leave footprints behind.
Fred & Maria Kearney
Sonoma 167RB
Our Pod 172
2019 Ford F-150 4x4 2.7 EcoBoost

offgrid

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Posted: 08 Sep 2018 at 4:30am

In addition to the bird problem you've got the noise. Someone in the campground is gonna complain that those 100 meter rpod mounted turbine blades violate quiet hours rules.

The solar vs. wind debate has been going on for nearly 40 years now. I keep thinking my side has won but there's still a bit more installed wind than solar capacity

Wind & Solar (worldwide)	Wind Total Capacity	Wind New Installations	Solar Total Capacity	Solar New Installations
2018 Forecast:	600.5 GW	60.9 GW	518.3 GW	113.0 GW
2017 Preliminary:	539.6 GW	52.6 GW	405.3 GW	98.9 GW
2017-2018 Change	+11.3%	+15.8%	+27.9%	+14.3%

Anyway, its back to hurricane tracking for me. 5AM forecast just came out. Florence's track keeps shifting south. I could use some of that good tequila over here. Stocking up at the ABC store is top priority in my hurricane emergency plan for today. Relocating the pod to higher ground has to wait.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

GlueGuy

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Posted: 07 Sep 2018 at 7:59pm

I have several neighbors who have attempted to use wind power. It is often the least expensive way to generate energy, but also the least reliable. Every single one of them has abandoned their wind power projects in favor of solar. Solar is hard to beat, no moving parts (other than electrons/holes), and a 20-30 year life span.

Wind power can work, but it needs to be up-scaled quite a lot. We're talking about wind turbines with 100' blades. Get that to work on your R-pod.

bp
2017 R-Pod 179 Hood River
2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

lostagain

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Posted: 07 Sep 2018 at 7:43pm

I'm far, far to lazy to go to all the trouble to take the concept to fruition. I'd rather go camping with my simple and easy to use flexible 100W solar panel. As we try to keep things to a minimalist's level, we've no need for such a Rube Goldberg contraption. [I still think it'd look really cool.]

As for cubes of wind speed, the only cubes we should really be thinking about are the number of ice cubes needed for a good margarita. But, as I previously observed, I would never waste good Herradura Reposado by putting it into margarita mix.

Finally, as for birds, it's a question of teaching them to get the heck out of the way when they see the Pod coming. Those that learn the lesson will also know to avoid all those propellers in the wind farms and those that don't, well, hopefully they're game birds that will go well with a nice sherry sauce.

Never leave footprints behind.
Fred & Maria Kearney
Sonoma 167RB
Our Pod 172
2019 Ford F-150 4x4 2.7 EcoBoost

offgrid

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Posted: 07 Sep 2018 at 7:27pm

Lostagain, i just looked up one on ebay, 130$, 400 Watts at 30 mph, startup at 4 mph, supposed to survive 110 mph. That is almost enough to survive the hurricanes out here on the OBX. Ask me if I believe it. I’ve been here in 115 mph winds. Not fun.

But at that price why worry about it? Hmmmm. But DW would reject the idea bc she wouldnt want me to be killing any birds.

One thing I can say about wind though is that it’s highly variable, energy generation goes with the cube of the windspeed. And its much more site specific than solar.

But if you know u have good wind access where you camp, go for it. I don't think the overturning moment from that size turbine would be that bad. With a very quick calc I came up with about 600 ft lbs at the roof of the rpod. Wouldn’t come anywhere near overturning your trailer. But I didn’t spend enough time on it to be confident. You could always stow it in high winds, you’ll need to do that to tow anyway.

Share some pics when u get it set up...

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

lostagain

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Posted: 07 Sep 2018 at 6:20pm

TheBum, sorry you live in such a high tax state. Here in Heaven/aka Nevada, I think the only tax you pay on propane is sales tax which varies county by county, but is always in the 7% range. I didn't count the tax in my suggestion of a price.

offgrid, yes, I was thinking of marine wind turbines. They are usually mounted on the stern rail, with a post to keep it up out of the way. I'd be a bummer to back into those spinning blades. The anticipated wind they have to withstand in normal use is often in in excess of 60 miles per hour or over 50 knots. Not sure what the wind speed is that they feather the blades and cut off generating. I think the trailer is in danger of tipping over before land wind speeds would become a problem for the turbine, assuming a solidly mounted post.

i suppose, like the high efficiency boiler PSEG wanted to sell me in New Jersey, it all depends on how much of the cost you can recover before you die or otherwise stop using it. Checking Amazon, they have some pretty interesting units (some regular propeller blades and some kinda U shaped) and they are pretty cool looking in the order of magnitude of $500, give or take a few hundred. Who knows how well they'll really hold up and what their real service life would be.

But the thing I like the best about the idea is how cool it would look on top of a Pod, centered on the forward roof, with struts connected to the aluminum frame on the side walls; like it's part of the propulsion system for the trailer. Wings attached to the back sides would really top it off.

As for me, everyday in my old age I have less and less reason to be law abiding.

Never leave footprints behind.
Fred & Maria Kearney
Sonoma 167RB
Our Pod 172
2019 Ford F-150 4x4 2.7 EcoBoost

offgrid

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Posted: 07 Sep 2018 at 6:09pm

For those who forgot or never learned the 3 laws of thermodynamics.

Snow’s corollary:

You cannot win (that is, you cannot get something for nothing, because matter and energy are conserved).

You cannot break even (you cannot return to the same energy state, because there is always an increase in disorder; entropy always increases).

You cannot get out of the game (because absolute zero is unattainable).

Or just remember the acronym TANF (there ain’t no free lunch).

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

offgrid

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Posts: 5290

Posted: 07 Sep 2018 at 5:29pm

Propane prices are really volatile (pun intended). And as furpod says swapping tanks at the gas station is the worst. But I admit to doing it often rather than trying to hunt down a place that will actually fill my existing tank. I’d rather be camping.. Here on the OBX it costs nearly the same to swap or get your tank filled because they can, it’s a tourist area and there aren’t many alternatives.

If you want to adjust the prices for the various fuels and for electricity for your area then you can just scale the numbers by the ratio between what I put in my spreadsheet and your actual costs. Or if you send me a PM I can send you the spreadsheet. I doubt things will change very much though in terms of ranking costs.

I’m thinking your wind turbine would be one of the ones sailors use? You’d have to figure out a quick sturdy mounting system, they need a lot stronger structure than solar. Might work great in the NV desert. Some Burners use them on the playa don’t they? Would be fun to do and a big attraction at your campsites 😜.

Wind is going to be like solar, you’re buying your energy up front. If you have extra, I’d use it instead of propane for the fridge and water heater. If not then run the propane.

You can go ahead and try to break the laws of thermodynamics. I’m getting too law abiding in my old age I guess. If you choose that path I also have a good deal for you on a bridge over the East River in NYC. Let’s talk.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

mcarter

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Joined: 07 Apr 2016
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Posted: 07 Sep 2018 at 5:02pm

Honestly I have monitored gas mileage on many trips. The alternator load didn't effect mileage in anyway. The AC did as did road conditions. The alternator output does change, the drag on the belt didn't change, the output of the alternator did. Because of demand. I like the effort but not sure that increased alternator output has a measurable difference to gas mileage and the cost of fuel.

Mike Carter
2015 178
" I had the right to remain silent, I just didn't have the ability."