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rippple
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# Posted: 5 Oct 2014 10:47pm
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Hey all, we're powering a 12x36 cabin. We have an infrared quartz heater using 1000w, a 4gal water heater, 1500w, 2burner stove,900w and 600w, small fridge, 1 lamp and Bunn coffee pot. We are wondering what size inverter, how many batteries, 12 or 24volt, and what size generator for recharging. Our cabin is on skids, and parked in a small campground with ac power avail till spring. I'm retired on a fixed income and will be acquiring these items thru the winter months. We are wired into a 30 amp breaker to receive 115v. But kinda rackin our brains finding advise. Help!
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ILFE
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# Posted: 6 Oct 2014 07:14am
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Brother, it will be considerably cheaper for you to stay connected to the mains as long as possible.
What happens in the spring? Will the campground disconnect the power?
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rippple
Member
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# Posted: 6 Oct 2014 08:58am
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We sorta put the cart before the horse, so to speak. We got deal on this cabin we couldn't pass up. So we put it in this campground while we secure our land. We don't intend to use any "grid" utilities at our lot. A generator will be the obvious recharging method, its all shade. So we have the next 6 months prepare our cabin and lot. Independent power is next on our list.
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creeky
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# Posted: 6 Oct 2014 09:25am
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Replace your heaters, stove with wood or propane.
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ILFE
Member
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# Posted: 6 Oct 2014 09:38am
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I'm with creeky.
Okay, lets look at your heater - just the heater.
Let's say you want to run it for 8 hours per day, while sleeping. Most likely you would run it much longer during the day. But, this is just to show you WHY you don't want to go this route.
8 hours x 1,000 watts = 8,000 watt hours, or 8 kWh
8,000 watt hours / 24 volts = 333 AH. You would need to double this to get any life out of your batteries. (You do not want to deplete your batteries beyond 50%.) You would need a 70 amp charger to keep up with that one appliance, daily.
This doesn't include the other (more than) 3,000 watts worth of appliances you wish to run through the day.
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ILFE
Member
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# Posted: 6 Oct 2014 09:42am
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Quoting: rippple We have an infrared quartz heater using 1000w, a 4gal water heater, 1500w, 2burner stove,900w and 600w, small fridge, 1 lamp and Bunn coffee pot.
I figure you could go with a wood stove for heating and cooking, maybe? Or, cook with LPG? Once you get the cabin where it needs to be, you could do solar water heating. The fridge, if energy efficient, could be LPG or possibly solar if by itself.
A Bunn coffee maker is an energy hog, I'm sure. I don't drink coffee or hot tea. I'm not sure what off grid folks do for their coffee fix. Maybe someone will chime in here to let ya know?
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groingo
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# Posted: 6 Oct 2014 11:16am
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I will jump on the Propane bandwagon as well, you could do a better job using much less electricity which is going to be your ultimate goal when you get onto your property, start cutting the electricity cord now or you will find it a lot more difficult and expensive if you wait especially if you have to use a generator to recharge your batteries, the bigger they get the more they drink the gas and that alone can get expensive quick!
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rippple
Member
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# Posted: 6 Oct 2014 11:58am
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Understood. Well onward and upward!
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rippple
Member
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# Posted: 6 Oct 2014 01:35pm
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Thanks creeky, great insight
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rippple
Member
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# Posted: 6 Oct 2014 08:24pm
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So the question still remains, dropping the heater, Bunn, and stove that leaves small fridge, tv, hot water heater, we still wonder, number of batts, size of inverter and generator for charging.
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MtnDon
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# Posted: 6 Oct 2014 09:23pm - Edited by: MtnDon
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The water heater is an electric resistance heater? Poor use of solar or fuel burning generator power, IMO. Electric heating of any kind is best done skipping the batteries and the charger and inverter, unless the heat load is short term, like a minute with a toaster. Batteries, chargers and inverters have inherent loses. It is normally best to burn the fuel to heat the water directly. Like with an RV water heater.
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Quoting: rippple we still wonder, number of batts, size of inverter and generator for charging.
You need to perform a best guess load estimate and come up with the watt-hours of electric energy needed for a typical day. That may not be simple, but it is necessary, unless you prefer guesses and the associated gamble..
The energy estimate will dictate the battery capacity which in turn will make it possible to intelligently pick a battery charger and a generator. (If you were thinking of charging batteries with the DC output like on a Honda/Yamaha inverter generator that is a poor use of the fuel. Those are low powered chargers.
The inverter size is determined from how many of your loads will be used at the same time.
Sometimes a generator powering an extremely well insulated electric water heater can save the day. The extra insulation can help hold the heat for half a day maybe.
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Also the small fridge... what kind? Is it a thermoelectric or does it have a compressor? AC/DC? There are some small refrigerators that would be great for off grid. And there are others that would be great energy hogs. 
Need more research, more details to avoid guesses and possible disappointment.
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rippple
Member
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# Posted: 6 Oct 2014 11:50pm
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Will do thanks much!
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sweet75
Member
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# Posted: 7 Oct 2014 09:28am
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I recently replaced a 3000w electric water heater for a liquid propane instant water tank by Marey.
Best thing I ever did as it saves my off grid system from getting drained within minutes.
The tankless unit works amazingly well and is easy to install.
http://www.amazon.com/Marey-1-3GPM-Propane-Tankless-Heater/dp/B00886GGOM/ref=sr_1_4?i e=UTF8&qid=1412688398&sr=8-4&keywords=marey+water+heater
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