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2400 sqft cabin - Need advice

Scorch

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I'm building a 2400 sqft cabin in central OK, and to run electricity will be fairly expensive ($20k+). The cabin will have about 1400 sqft of south facing roof at a 5/12 pitch which would not be shaded. I'm considering whether it is feasible to go solar. My biggest concern is running the AC in the hot Oklahoma summers... Anyone done something similar to this, and can I get enough generation/storage to make this feasible? Anyone able to ballpark a total system cost?

Thanks in Advance!
 
I'm building a 2400 sqft cabin in central OK, and to run electricity will be fairly expensive ($20k+). The cabin will have about 1400 sqft of south facing roof at a 5/12 pitch which would not be shaded. I'm considering whether it is feasible to go solar. My biggest concern is running the AC in the hot Oklahoma summers... Anyone done something similar to this, and can I get enough generation/storage to make this feasible? Anyone able to ballpark a total system cost?

Thanks in Advance!
Step 1 is an energy audit.
See my signature to find a helpful tool.
 
The best roof pitch for solar in your area is 7/12
I'm guessing based on the links you sent, that if I want to maximize energy production in the summer when I need the most energy to power the AC, then 8-12 degrees is probably the best angle, but that would only be 2/12. Looks like 4/12-5/12 might be a good compromise.
 
I'm guessing based on the links you sent, that if I want to maximize energy production in the summer when I need the most energy to power the AC, then 8-12 degrees is probably the best angle, but that would only be 2/12. Looks like 4/12-5/12 might be a good compromise.
Is snow load an issue where you are?
 
Is snow load an issue where you are?
Nope. Shouldn’t expect more than a couple falls a year of only an inch or 2. Also this is primarily for 3 season use (vacation home) so no biggie if we can’t produce enough after a snow.
 
Having a big array of panels stationary on the south-facing roof is convenient, cheap, and very stable, but you won't be producing much power after about 4pm. In addition to your roof mount, you might also want to add a ground array or two that can face East or West, depending on when your power needs maximize. That way you'll have enough solar to power the air-con after 5pm without depleting your batteries.
 
The cabin will have about 1400 sqft of south facing roof at a 5/12
How about East and West? You can extend your solar day quite a bit if you have panels facing in three directions.

I don't think I have ever heard "2400sqft" and "cabin" in the same sentence :p That's almost as big as my 4 bedroom two story house....
 
My cabin is 2850 sq feet , I guess the cabins are getting bigger .
I have 4500 watts of solar mounted on the back side of the roof in the pic
I have 4500 watts of solar that needs to be ground mounted at some point .
I use 16 golf cart battery’s for power storage .
I have a out back flex power one ,36/48volt system with one 120v inverter one fm80 charge controller .
Mate system with hub and flex net battery Monitor .
Breakers and switches are on the side of the unit
It was very easy to set up.
I bolted the panel to the wall made a few wire chases and hooked up the battery to the inverter , solar panels to the
controller , made a battery box with power vent .
On day one in about 2 hours the unit was on the wall with 8 battery’s and 900 watts of solar charging the system .
I’m in for under 10k but need to spend more money on a second charge controller mounting and breakers
The house is on a concrete slab with tile floors and radiant heat .
The porch keeps the sun off the walls , the concrete slab keep the house 67o i have 9” thick walls filled with insulation .
I don’t use AC I have to open the windows to warm the house up in July .
I use about 10% of my battery over night this time of year .
in the winter I use 15% of my battery over night and charge with a 2800 watt Honda every day or so .
I use 5 gallons of reg gas a week if the panels are covered in snow .
I can heat with wood , if I want I could run AC in day light hours To cool the place off .
Yes the solar panels where covered with snow for 10 weeks this year .
Last year there was not much snow so I used 15 gallons all year .
262E2EC8-5B52-40BD-AE2F-7DA893433A83.jpeg0A2C0161-BFD0-4C73-ABA2-F4911E487477.jpegCA744A2A-FE94-4DC7-8BF0-84D25205D89E.jpeg
 
ye,
running a offgrid bunker ^^

8400 Watt Solar Panels
400 Watt Wind Generator
3x Deep Cycle Batteries at 24V : 1150 AH c5, 740 AH c5, 720 AH c5
2x High Frequency Inverters 2,4 Kw
1x Low Frequency Inverter 3,6 Kw
3,6 Kw Gasoline Generator Multiphase 220/400 Volt
3,2 Kw Gasoline Generator Singlephase 220 Volt

Water
Main water sourced thru well, 45m drilled hole, 450Watt Pump.
Secondary water sourced thru rainwater harvesting into 2x 1000l barrels for gardenwater.

Heating
25 Kw Stove for logs or coalbrickets. -> heatexchanger to heat watercycle ( 19/6 Kw for Water/Air).
28 Kw Automated. Heating for pellets, coal or logs. -> heatexchanger to heat watercycle ( 26/2 Kw for Water/Air).

-> video of my power setup ->
 
Thanks everyone for your input....

So after filling out the audit spreadsheet, it appears I need about 8kw of power, and storage of about 34kWh (700Ah at 48V).

So I believe I need the following (with estimate costs)... Remember, I am a total noob at this, so let me know if I'm way off with any of this.

nameDescriptionnumberprice eashippingTotal
Magnum Energy Pure Sine Wave MS4448PAEInverter/Charger, 4400 Watts, 48 VDC
2​
$ 1,900.00$ 3,800.00
Ampere Time Lithium|LiFePO4| Rechargeable Battery48V 100Ah 4.8KWh
7​
$ 2,500.00$ 17,500.00
SanTan solar panel -UsedSanTan Solar T Series 250W Silver Frame - Used (65" x 40")
40​
$ 50.00$ 600.00$ 2,600.00
mounting hardwareestimate $30/panel
40​
$ 30.00$ 1,200.00
Generac Generator15kW propane Generator
1​
$ 4,150.00$ 4,150.00
TOTAL:$ 29,250.00

Does this look reasonable? Am I missing any major components (obviously the wiring, but what else)? I'd probably end up getting more panels to be safe since I have a 1200 sqft roof and it seems that 40 will only take up half of that.

I'm assuming I need 2 of the magnum inverter/Chargers, since I only need about 8kW max output, even though I have designed with 10kW of solar panels, or would I need 3 of those units? Is it better to get separate charge controllers and inverters?

Also, when I was looking through the Magnum documentation it seems like the batteries will only charge if there is no load on the system... is that correct? So even if I'm producing 6kW of energy and only using 1kW, the batteries would not be charging? If that is the case, would having multiple inverter/chargers solve that problem so while one inverter is powering, the other inverter is charging?
 
It seams like a lot of power usage .
My house runs on 2/300 watts un less I’m doing some thing out of the ordinary.
a 4000watt inverter will surge to 8000watts
I would try to design a house that can run on less power .
I would look at a company that makes a complete system that can be linked together .
Magnum did not have a complet system when I was looking .
I went with outback 4 years ago to day snider seams a little better but I just don’t know.
Regular quality charge controllers will take 4500watts of solar @48 volts , so 2 charge controllers will take 9000 watt +-
with 9000 watts of solar I can get 500/ 800watts per hour all day on the darkest rainiest day in December
So I can get full charge if the panels are not covered in snow .
300watt panels work out better for a 48 volt system 3 series 5 strings max out a charge controler with a little over paneling 4500 watts .
There is no problem with charging , it is mostly all automatic .
When you start charging the battery’s the inverter stops inverting and starts charging .
The generator powers your loads seamlessly .
15kw genarator is big , I use a gas Honda 2800 watt unit .
The thing is my 3600watt inverter uses 2000watts of genarator to charge the batterys .
Then my house uses 2/300 watts to run , soooo 2400 watts and I have 400watts left over ?
of course 2 inverters charges twice as fast so you could use a larger unit but 15kw is a lot .
17k for battery’s ( ouch ) you have to realize you can run all day off thebsolar panels .
Even if you run ac all day when the sun is out you don’t use battery power .
I’m sitting here now with every thing running frige and small freezer 6 ‘ tv cell booster lights 2 ceiling fans
And I’m drawing 200watts + and my 430 amp hour battery is sitting at 96% full , I’m going to bed and in the morning
I will be down to 90% I turn off the tv , lights but every thing else stays on .
Tomaro I will be in absorb by 900am and at that point I can run off solar all day .
In my area used solar panels won’t pass inspection they need to be UL listed used panels have no stickers .
My panels cost 137 buck each and then 160ish for the second batch .
I just picked them up at my supply house . So no shipping .
 
Let’s start by saving $7000 on your batteries ?

See here:


These are $1500 now so that’s where I got the 7k savings.
 
Let’s start by saving $7000 on your batteries ?

See here:


These are $1500 now so that’s where I got the 7k savings.
More like 10,000$. Just installed twelve of the new Rolls 4V 17P batteries this last weekend for my 48V system. Cost was 7473$ delivered to my front door. Even assuming I should only use 50%, that's almost three times the Ah for less than half the money.
 
Thanks so much for all your replies.... looks like I can be off grid for alot less than the cost of running the power lines to the house.....

On a new build, I'm assuming that I can get my roofers to install the racks and panels, and any competent electrician should be able to wire it all together assuming I get all the right equipment together, and ensure it's designed properly with decent schematics for them to follow. (I would DIY it, but I really just don't have the time).....

When I get closer to finalizing an order, I'll post it here for review as well.

FYI - I contacted a "Solar Installer" and they estimated the cost to be in the neighborhood of $100,000!!!!!
 
My cabin is 2850 sq feet , I guess the cabins are getting bigger .
I have 4500 watts of solar mounted on the back side of the roof in the pic
I have 4500 watts of solar that needs to be ground mounted at some point .
I use 16 golf cart battery’s for power storage .
I have a out back flex power one ,36/48volt system with one 120v inverter one fm80 charge controller .
Mate system with hub and flex net battery Monitor .
Breakers and switches are on the side of the unit
It was very easy to set up.
I bolted the panel to the wall made a few wire chases and hooked up the battery to the inverter , solar panels to the
controller , made a battery box with power vent .
On day one in about 2 hours the unit was on the wall with 8 battery’s and 900 watts of solar charging the system .
I’m in for under 10k but need to spend more money on a second charge controller mounting and breakers
The house is on a concrete slab with tile floors and radiant heat .
The porch keeps the sun off the walls , the concrete slab keep the house 67o i have 9” thick walls filled with insulation .
I don’t use AC I have to open the windows to warm the house up in July .
I use about 10% of my battery over night this time of year .
in the winter I use 15% of my battery over night and charge with a 2800 watt Honda every day or so .
I use 5 gallons of reg gas a week if the panels are covered in snow .
I can heat with wood , if I want I could run AC in day light hours To cool the place off .
Yes the solar panels where covered with snow for 10 weeks this year .
Last year there was not much snow so I used 15 gallons all year .
View attachment 48073View attachment 48070View attachment 48069
Wow, some people's version of cabin sure is a lot different than mine... beautiful place.... if that's your "cabin" I can't begin to visualize your normal house.
 
Thank you very much
My regular house is 1000 feet larger plus bacement and 4 car garage .
I have a ton of kids .
I think it’s really to big but wifey made the plans , and I just built it with one of my sons on weekends .
I’m a builder so it’s no big thing for me .
I bought the top of the Mountain so , I may build some thing smaller on the other side and give this one to one of the kids or sell it ?‍♂️
 
??????? those solar guys are funny .
For 100k you should find the time , that is a bad Neighborhood to be in .
Really solar is not electrical work it’s a different set of rules and skill .
I used iron Ridge 1000 because of high wind and heavy snow.
I staggered the feet so they where not on the same rafters .
The roof was on , so we hammered nails down to find the beams .
Then layed out the panels starting 40” from the side 36” down from the ridge .
the iron ridge mounting system is great .
Our shingles where strait so we just lifted a shingle , slid in the flashing caulked around the area with polyurethane flashing tar lined up with the shingles and drove a 8” SS lag bolt into the rafter below .
we did this late in the day .
It took 4 hours total over 2 days
we ran 10 wires to a disconnect below with steal conduit .
The wires get ends crimped on neg pos then snapped on to the panels .
The panels get wired together as you go , and the wiring gets zip tied to hold it off the roof .
I worked the ground and my son worked the roof , it’s a 10/12 pitch good for year round power production , not to good for working on .
It took us 2 evenings to get it wired up , it was 95o and the panels where hot ? .
My son is 6’5” so he could just walk up the roof and screw the panels on by him self , they are 5’5” tall x40” wide
The hard part is getting every thing together .
You don’t get a diagram to follow ,
You have to read all the manuals and figure it all out , I had the engineer from Arazona Wind And Sun on speed dial for a couple of days so I could ask questions .
I love diy stuff, but i could not spec the parts by my self .
I just called arazona Wind And Sun and told them what I wanted to do , and in 12 hours I had a itemized quote
with every thing but wire .
I bought the out back flexpower one from them , but my Electrical supply house sold me everything else with a big savings
I just loaded every thing up at there shop . So no shipping .
My system was 10k plus’s a few other do dad‘s 3/4 years ago . I have 32 panels with only 15 wired in and one extra mounted on the roof .
So this system could cost 13k + if you add on the COVID ? money I think . Arrrrrrrrrr .
2095F9F0-35DD-4D7D-8460-67D855D45DE4.jpeg
 
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