Is this even possible?

DaddyRabbit

Brand new to all this, so please be gentle. We are planning to set up an off the grid retreat for two families. When I say off grid, it's probably 20 miles to ANY grid. Initially we would use camper trailers and possibly build cabins later.

The big question is, can a solar system be built that will provide electricity for two families (two refrigerators, two microwaves, normal lighting, etc.)? I've been told that with a large enough bank of batteries, we could even run small air conditioners to sleep at night (after all, this IS Florida).

I'm sure if my last name was Trump, it would make it easier. But then I would have to put up with that HAIR! So, #1. Can it be done? #2. Can it be done reasonably? #3. Where the hell do I start?

Thanks in advance for the help and advice. And keep in mind, I am not fluent in engineering!

Cariboocoot

Re: Is this even possible?

Welcome to the forum.

Yes, it can be done!
But you might need to be Bill Gates.

No, seriously. You start by figuring out your potential loads. All off grid systems need to be designed from those numbers. Starting any other way leads to headache and heartache and other anatomical pains.

So you need to know the highest Wattage that the system(s) will draw at any one time and the maximum Watt hours that will be used in a day. The best way to do this is to get a Kill-A-Watt meter and, if you can, actually run your prospective loads through it for a few days and get some "real world" numbers.

My off-grid system runs a refrigerator, computer & satellite modem/phone hook-up, water pump, digester pump, lights, and even microwave. It's a tad undersized for the unattentive, but I squeeze every Watt hour I can out of it. Roughly $8,000 in equipment. Some prices have come down since, others have gone up, and everything is cheaper in the U.S.

In general, such off grid power costs around $1 per kW hour over the expected lifespan of the equipment.

DaddyRabbit

Re: Is this even possible?

Thanks for the quick response, Cariboo. At least I haven't spent any money yet, so I haven't screwed up. Before I spend any, I'll get the Kill-a-watt and do the homework. I might have to do it in stages. Any advice on that?

waynefromnscanada

Re: Is this even possible?

If it were me thinking about such a set up, I would want to go with two separate systems, that way if one party overuses power and runs down the batteries, they have no one to blame but themselves. Going big enough for two families I would think would cost about the same as two single systems, and if one of the two families hog most of the available energy, the result won't be hard feelings, stress and hostility between neighbors. That's something to seriously think about.
Keep in mind too, that probably the most important thing about living on an off-grid system, is one word, repeated over and over again. That word is: Conserve, Conserve, Conserve! It's far cheaper to conserve electricity than to build a system big enough to handle unnecessary and frivolous waste. For instance, which would you rather do - - stand there gazing into the open fridge while you wonder what you might like to have for dinner, or would you rather have lights for the evening? It will require a different way of thinking and living, if you and/or you're family are like most North Americans who were brought up to accept gross energy waste as a normal way of living and don't see that waste for what it really is. To build a system capable of running a normal AC through the night will probably more than double, and perhaps even triple or quad the cost and size of the off grid system, depending on the size of your AC and it's use, but it can be done. And when purchasing your appliances, your #1 item of importance should be the energy consumption of each item. Average fridges and freezers are notorious energy hogs, so pay very careful attention and do a lot of investigating before you purchase. You can do it. Many of us already have.
Good luck, and I'm sure you'll get a lot of good, honest, no BS help and information here on this form.

Peace

Cariboocoot

Re: Is this even possible?

Yes; it's difficult.

Depending on how much "future expansion" you need to do you can sometimes end up starting over, or at least building a completely separate new system.

For instance, to support a couple of campers you might set up a small, strictly DC 12 Volt system. This is usually the amount of electric available in the average RV or trailer. But it won't do you much good when you go to run an AC unit a couple years down the road. When the power consumption goes up you need to increase the system Voltage to keep the DC Amps manageable. That usually means tossing everything and starting over. One exception to this would be the charge controller: you can buy an expensive MPPT type controller to begin with which will allow 12, 24, or 48 Volts output at 60 Amps. Might be overkill at first, but it allows for a lot of expansion. The other solution is to keep the small system for lights and add a big system for high power use.

There are other expansion problems too: you can't always get the identical panels you bought 'X' years ago, which can be problematic. Old batteries and new batteries do not mix well. If you can plan your "now" system and your "later" system to begin with then you can see where the two could potentially share components and/or what would be involved in the upgrade.

Also you'll want to remember the #1 rule of off grid power: conservation. Forget anything with electric heat and try to keep the loads down as much as possible. In the case of Air Conditioning, look at the Sanyo mini-split machines. There's quite a lot of discussion about them around here; favourable reviews. In fact a casual perusal of the whole Energy Use & Conservation section may give you some good ideas.

DaddyRabbit

Re: Is this even possible?

Thank you again. I'll try to digest this and do some homework. I'm sure I'll be back for more.

Photowhit

Re: Is this even possible?

I live in and work security for an owner owned camping area (2600 acres, Wildwood Estates.)

I had lived off grid for several years, with a minimal system (220 watt array), dealing with summer using fans only, I decided I wanted/needed A/C. At that point I was living in a camper and I would not try to air condition a camper even in Missouri. It just has too little insulation to make it practical.

I purchased and additional 920 watts of panels (and moved to an almost ideal spot for solar) and built a small 10x16 cabin(w/sleeping loft) with 6" thich walls and well insulated floor and ceiling. Here heat and sun come together and I can feel comfortable if I followed through on my plans to do at least a 440 amp battery(8 golf cart batteries) bank, I could run the A/C enough to have comfortable summers.

I already had 4 golf cart batteries and as others have pointed out you don't want to mix old and new batteries. So I ran the 5300 btu 10.8 window shaker for 3-4 hours a night on thermostat and during the day after the batteries went into float. I think I had enough charging to comfortably extend that to 8 hours on thermostat at night, but my storage capacity wasn't large enough. The A/C makes up 90% of my summer load! Only a fridge draws significate power other than the A/C, I have no well pump, Lights, TV, computer are all minimal uses.

I once lived in the great sunshine, sweat box of north Florida (your camping in Apalacheecola, Ocala, or on an island...) I'm not sure you could do it there as I've seen night time lows of 80 degrees in January north of clearwater(OK I think officaly it got down to 78 but that was also the dew point!), and hazy days when I would only get40-50% production out of my panels during the day, and then there are the afternoon clouds and every day showers.

Ever think of vacationing in the Smokies (though it was all cloudy and drizzly there, but if you could get inside you wouldn't have to worry as much about cooling, or you could move out here to Missouri, 6 weeks of pretty hot weather in the summer and 10-12 weeks in the winter, beats 26+ weeks of summer for me! (and a few sub freezing days in winter)

If your near Tallahassee Florida, stop in and talk with Al Simpler of Simpler Solar Systems, he's been there for 30+ years and will know the enviroments yor dealing with. Hope a local store is OK here Mod squad.

BB.

Re: Is this even possible?

Not a problem... We do like to hear about the good guys out there too.

-Bill

DaddyRabbit

Re: Is this even possible?

Thanks for the pointers, Photowhit. We might try to run the air on a small diesel generator. It might make more sense. But we are also looking ahead to a time when fuel might not be available at any price. Hopefully, we always have the sun.

I've lived in North Florida for 40 years and I don't remember ever having night time lows in the 70s in January. But it can get muggy the rest of the year.

Thanks all.:D

DaddyRabbit

Re: Is this even possible?

Thanks Wayne. That is a good idea. Especially considering that one family has 4 members and the other 2. There could be a lot of stress in those situations without adding to it.

Photowhit

Re: Is this even possible?

DaddyRabbit wrote: »

I've lived in North Florida for 40 years and I don't remember ever having night time lows in the 70s in January.

"I've seen night time lows of 80 degrees in January north of clearwater"

Very serious, I was visiting my sister in Tampa and went down to Venice to photograph at the rookery behind the courthouse, and tried to camp out in the back of my pickup north of Clearwater, but I know it can get very cold in North Florida, I've bicycled from Tallahassee to St. George on a day it didn't get over 40 (maybe a tad with the gulf affect when getting close. I would have quit but I was cycling with my brother both home for the holidays, with folks in a cottage at St. George.

Do stop in and see Al, hard to beat 30 years of experience in Florida's harsh climate. He's not always easy to talk with. Use to do lots of island and third worls projects, but is becoming more local with the tax credit.

There is also was a sustainability or green living Expo, my mother use to help with, I think it had a date problem this year, it was in the early spring. Worth checking into. I think BBCAT (Big Bend Climate A%%&$# T@##) is still active, they stopped a new coal plant from coming into Taylor county.

And good luck! I couldn't handle the weather there! More power to you!

techntrek

Re: Is this even possible?

You can buy campers now-a-days with 2" of insulation, where most on the market now only have 1". Either way, the key will be to get the campers into the shade for most of the day. If you can't get them under trees you will have to erect temporary tarps overhead or open-sided pole barns. Give yourself 2-3 feet of airflow between the camper tops and the tarp/roof. Also extend it out in all directions a half-dozen feet to provide shade on the sides of the campers in the late morning and late afternoon. Properly designed homes do the same thing with the roof overhang and/or porches.

That takes care of the heat load from direct sun so you can make the power system smaller for the A/C. Yes, you can use A/C but there are some gotchas. You could use a genset as you already mentioned, but even getting it 100 feet away and sound-blocked with some sand bags you'll hear it. All. Night. Long. So do consider PV for it, but don't plan on using the standard A/C that comes with your camper. Modern RV A/Cs are much more efficient than older ones (my old popup needed 1600 watts to run, my new travel trailer only uses 1000), but still not as efficient as what you'll need. Get a mini-split A/C for each trailer, search around here and you'll find very long threads on them. With that in place you could run it on low for two 8 hour nights using 6-8 batteries. Your PV will need to be designed large enough to recharge them within 2 days during the week when you are gone, plus give you enough to run some fans when you sit outside during the day. I'm assuming you will only be in camp for the weekend. If you are looking at week-long trips or you must have A/C during the day you are back to needing a genset during the day. But still better than listening to it overnight.

Next up are your non-A/C loads. With campers you are 1 step ahead of the game, plan on using your fridges in propane mode. They sip propane, the smallest can go a month on one 20 pound tank, the largest a week or more. You could go as far as having a 100 gallon tank installed on the site with the proper fittings if you will also be using propane to cook and for heat in the cooler months. Heat is the biggie, camper heaters slurp propane especially if your camper is big and only has 1" of insulation. My camper is only 18 feet long and has 2" of insulation so it sips propane most of the time. Design the PV system to provide 12 volts directly, don't use 120 volts to run the converter which will inefficiently provide 12 volts. Don't plan on using curling irons, hair dryers, electric coffee makers or electric griddles.