House System

I was not really sure where to put this since it includes solar, propane, and wood. If this is not the right place, please relocate. Well, I have been thinking about and doing a little research on how to power my house I am planning to build in the next 12 months. My goal is redundancy, not really off-grid per se. My thoughts were:

Start off with a battery bank big enough to power the whole house (less a/c) and have enough "juice" to power the house for 2 days. I am estimating about 10kw peak energy. With this I will power lights, well pump (more on that in a bit), computers, TV's, refrigerators and freezers. Then, have a solar array tied to this batter back up that will recharge the batteries, obviously, when the sun is up. I would also have the battery set-up grid tied to "top off" any deficiencies each night. I am assuming I will need pretty consistent grid power, probably every day, since I doubt the solar array will be enough to re-charge the batteries each day. Oh yeah, I am in South Carolina by the way...

I will then power stove, oven, heat and a whole house generator from a 500 gallon propane tank. The generator will only be for when the grid goes down and be big enough to recharge the batteries every ~20 hours or so. Heat for the house will also be provided by one of those "central" outside wood burner.

To minimize at least some of the power requirements I am thinking of getting a 500 or 1000 gallon water tank lifted in the air. The well pump will just refill the tank. I think I could get a much smaller pump if I am just topping of the tank each night. This elevated water tank will also provide better water pressure to the house. It seems like water pressure to some of the houses I go to in the country have sketchy water pressure.

I will tie the A/C directly to the grid and will only be powered by grid power. Grid goes down I am not running a/c.

So, my new permies friends, what do you think of this set-up? Never work in a million years? Easy?

Very possible. It has been done. Batteries are BIG, HEAVY, EXPENSIVE, and a PITA. Just researched it myself (again) and adjusted my expectations.

Paul should do an article on battery suck factor and start the discussions on alternatives. Just a reminder, every dollar you spend to reduce demand will save you $5-10 in batteries, inverters, and PV.

For example, you can spend $400 on a huge pressure tank for your well so you can not run your pump for a whole day just from the tank. Then you only have to run the pump during the day when you have solar, or while running the genny. Use a composting toilet will save water BIG TIME with a family, helping that pressure tank make it that much longer...

My plan for water is to have a cistern to store water so I will pump from the well on solar ONLY and then run a DC pressure pump (high-end RV pump) from the battery bank. Total cost for a two-stage system is considerably cheaper than doing everything with one deep well pump whether it is AC or DC.

Magnum Energy makes really good inverters for grid-tie in their BOATING line. Evidently shore power for boats is very unreliable so their inverters act as a whole-house UPS with smart battery charger. http://www.magnumenergy.com/Products/MS-PAEseries.htm
You will need 2 of those inverters stacked to get 10KW and a garage full of batteries. But only if your garage has air conditioning--you need to keep them COOL.

Go over to http://www.thesurvivalpodcast.com/tag/steven-harris and listen to all the podcasts on blackouts, generators, and battery backups. Then re-adjust your expectations to your budget.

If you can figure out how to get under 2 kW things get so much easier. Even if you need more power once in a while, you can cover the peaks with a genny.

Everything is always more complicated than it seems, right? I had forgotten about keeping batteries cool and that kinda thing. I have actually listened to most of Steve Harris' podcasts over there with Jack. I guess I would probably need to get the power consumption down some. As you have probably guessed I am pretty new into this. I have a little time to get it straight...

Btw, how well do you think using a rain catchment type system from the roof for toilets would work? I live in lower SC and get about 47 inches of rain a year.

I'm headed down the same road you are talking about.

One thing I'm in the middle of right now is trying to get 12v Led lights. The LEDs are much more efficient than incandescent or cf lights. Running them on 12v directly from the batteries will save the cost and efficiency of the inverter. The same would apply to what R Scott is talking about with the rv pump.



Check out nickel iron batteries. You pay a serious premium to buy them but they don't need to be replaced like lead batteries. They are almost impossible to damage from missuse.

Sebastian Mencius wrote:Btw, how well do you think using a rain catchment type system from the roof for toilets would work? I live in lower SC and get about 47 inches of rain a year.

It works great. You need to make sure the water is clean enough to not cause the valves to leak (fill or flush). They fill much slower if based on gravity pressure, but that isn't a problem for most families.

Electric:
get a 3KW solar panel for $3000, and only use electric while the sun is shinning, as long as you dont open the freezer in the it should stay frozen for 3 days, same for the fridge at night all you well need power for is 6 LED bulb @ 15watt each. so a sub 1000 Whr batttery pack ($1000) should be more than enough.

Heating:
Use 12inch insulation (SIP) about ($6,000) when you build that will lower your heating and cooling needs. In floor radiant heating/cooling pipes will go a long away.

Cooking:
Solar cooker and a solar oven is another option to try out.
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