Build Design On My First Off Grid System 13KwH

[vinniethePVtech]

I will try to keep this short.
My home in the winter consumes 61.44KWh day when the heat pump is in use, the break down in 24 hours would be 2.56 KWh . I've modestly rounded out to 2.8KWh, which would be 67.2KWh day.
Concord California Sun Hours are recorded on a modest 5.6 of consistent sun. I am assuming I will need roughly a 12~13KWh array.

5.6 sun hours X DC side 12.3KWh = DC side 68.8KWh DAY

So I selected a panel that when in a string of 2 is suitable for 48V.
SUNTECH 205W 26.3VmP 7.8Imp
26.3VmP X 2 = 52.6VmP
Combined 10 Strings = 78 Imp

So now I would duplicate this 3 times.

Total of 3 sets of arrays
Total of 3 sets of combiner (midnight solar 12, 10-150V breaker/15 amp)
Total of 3 set MPPT outback 150V, 60~80amp
Total of 1 Combiner 3 string
Total of 1 battery bank string of 4 surette 48v, 357Ah (seems to be the best choice recommended by Sunking)
Total of 1 sunny island inverters 4248U
1 pole DC disconnect (fuseable)
1 pole AC Disconnect (visable and fusable)

AC side result should be roughly 54.35KWh DAY.
My fiancee and I realized that we would need to make some cut backs. First one would be to use the heat pump less, or have it removed as the unit itself is 25 years old and isn't efficient.

Now my question is some one with off grid design build will the equipment I want to use for this set up work. Or will I need a higher voltage panel?
Total system $42,404.10

[russ]

In the winter your area receives approximately 3.4 kW/day with an annual average of 5,47 (close to the annual average you have). With off grid the worst case (Dec-Jan) are what counts - the annual average is meaningless.

Per kW of panels PV Watts says you will (on a 10 year average) generate 1427 kWh per year.

For that size of system to have an Off Grid system you will have to sell your grandchildren into slavery for the next 100 years or so. You would be looking at approximately 25 kW of panels to cover the December/January period.

The heat pump is no doubt a real energy hog - you should look at the energy consumption of all consumers in the home and replace where ever it makes sense. Conservation is normally a much better investment.

You battery bank size is off by a few thousand percent - way too small for your load. You would also need a generator capable of charging the batteries in the event sun is not available- such as during a storm.

You are looking at a couple hundred thousand for your desired configuration.

Rethink it and go with grid tie - should be a much better deal - then the utility is your battery bank. If you have net metering you can possibly use excess summer generation for credit for winter consumption.

[vinniethePVtech]

If I completely do away with the heat pump. I can save 1.3 KWh a day. Then the system would be over power minus an additional battery bank.

[russ]

If I completely do away with the heat pump. I can save 1.3 KWh a day. Then the system would be over power minus an additional battery bank.

1.3 kWh per day?

[vinniethePVtech]

1.3 kWh per day?

Sorry I meant 1.3 kwh , 31.2kwh day

[Sunking]

Vinny this is insane to even consider going off-grid. With your winter insolation of 3.4 Sun Hours using 31.2 Kwh per you need a 14,000 watt solar panel array, 4 80 amp charge controllers. 8000 pounds of batteries, industrial grade inverter totaling well over $70,000 just in the major equipment not counting the all the misc material, equipment EPA permits, local permits, labor, and engineering fees. By the time you add it all up you are staring at $150,000.

The fun part is those cheap batteries that cost you $21,000, will need replaced every few years at even a higher cost, and the paper and legal work to dispose of them will be expensive.

This is just plain insane.

[vinniethePVtech]

Vinny this is insane to even consider going off-grid.

Yes I am crazy. I have flash fevers and am fighting off throat cancer and told I could die tomorrow. So yes I am crazy and walk that fine line.
I am going off grid because I'm tired of getting un expected bills in the $300 range for a 1200sq/ft home in the winter because I like to keep my 2 year old son and my 2 step daughters warm. Besides I hate the bureacracy of PG&E, and the state of california. So the state wants me to go green? Fine I will, but I won't stimulate the grid, at my expense, and I won't help PG&E that will continue to hike energy costs as I could stimulate that grid.

With your winter insolation of 3.4 Sun Hours using 31.2 Kwh per you need a 14,000 watt solar panel array, 4 80 amp charge controllers. 8000 pounds of batteries, industrial grade inverter totaling well over $70,000 just in the major equipment not counting the all the misc material, equipment EPA permits, local permits, labor, and engineering fees. By the time you add it all up you are staring at $150,000.

You are forgetting.
I get materials at 10% discount for being a contractor. Permits? Seriously? I was just going to disconnect at the main panel so PG&E doesn't call variance if i was to get into their metering section. Its legit and what they won't know wont hurt them their meter will just read 0. Rebates, credits, don't care I will write it off under my home office. chinese panels are so cheap they are half teh price of teh competitors.
Labor is not a problem my family is a family of contractors, its free, and my brother is NABCEP certified and my sister is a project engineer. I have friends that want to learn solar at my expense of $100 day and a 1099 form, besides I would rather build it myself and self perform.

The fun part is those cheap batteries that cost you $21,000, will need replaced every few years at even a higher cost, and the paper and legal work to dispose of them will be expensive.

Just found a recycle/dismantler that will actually pay me $30 to disassemble the batteries and recycle what ever they can get from them. I will go with this solar setup discussed, with the addition of of another battery bank to reduce load on the batteries, and retain a lower percentage on D.O.D. I am adding a generac 7000W propane/natural gas generator for winter use. It's CARB legal for California emissions.

This is just plain insane.

Maybe, but this is more about life lessons, principals, and values. I do this for my kids. My gift to reduce my carbon footprint, it will teach my kids, how to survive on their own. I do this for my family and don't need to depend on society or a grid to do it.

Total cost is at $62,289.00 my budget is stopping here and I am going to start sourcing parts as they come. Build completion should be in under 2 years. No permits, no credits.

[russ]

You are pursuing foolishness so you can be green - maybe some equally loony friends will be impressed but not any sympathy from us here.

You still need building permits, electrical inspections and all or else you can end up in deep soup.

For others that read this - Vinnie is talking about playing a dangerous game - not to mention a loser as far as economics go. Many aren't happy with their utility but you folks are forgetting that the state tells the utility everything it can or can not do and how much they can charge.

Grid tie makes far, far more sense - simpler and cheaper. If one is worried about emergency power just have a small generator in the garage that can be used if there is a power outage.

[vinniethePVtech]

You still need building permits, electrical inspections and all or else you can end up in deep soup.

So are you a contractor? Have you ever been red flagged, doing work within your own home?
Inspectors are only in place as a third party entity to verify that the work between customer and contractor is legitimate. Also so an assessor can evaluate property for taxes. Has nothing to do with PG&E. Now if I was to steal power from PG&E thats a whole different problem. If I chose to disconnect myself from the grid, that's my concern

I would never build solar on any one else's home without permits, my insurance wouldn't allow it and I could be sued.

If you trust your engineer, or your own methods of building in your own home then do it.

You just seem to bland and boring for me RUSS, add a little excitement to your life.
Stop being a hypocrite, your own moderation Mike is going off grid, and you don't seem to be saying a whole lot of crap about what he wants for his home?

You are pursuing foolishness so you can be green

You can write off a solar system, you can't write off electrical bills. Its more than going green, its the luxury of control, write offs, and I think I said a luxury. Proving for a home office what is spent for electrical bills almost becomes a moot argument when audited.

[russ]

Quit with the blather - you claim to be the 'PV tech' and seem to know amazingly little about that or contracting.

1) I had a General Contractors license in North Carolina for many years

2) Mike went off grid because it was going to cost a fortune to bring power to his home from the main line - PV was the lesser of evils.

3) The permit and inspections are to insure all is done correctly - even within your own home - thinking of future owners more than the present occupant. If you don't know this you are not a licensed general contractor.

4) PG&E could care less if you disconnect - in 1000 years they would not see it on their balance sheet.

5) You are constantly bombarding the community with blather about things where you seem to have overheard someone talking. You don't know contracting, you don't know PV and on and on.

[russ]

The tax write off - you may be able to write off the percent of your home that is a dedicated home office. Not being a tax accountant I can easily be wrong but I expect the IRS would be looking at what percentage the office might actually use.

This write off (home office) is a favorite of the IRS to catch people with - not a good place to cheat.

[Sunking]

Vinny bottom line you just chose to pay around 10 times more for electricity for the rest of your life, well maybe 5 to 8 in California. You are not screwing the electric company.

[Mike90250]

4) PG&E could care less if you disconnect - in 1000 years they would not see it on their balance sheet.

No, but you will get a "monthly disconnect fee" for the privilege of having power in front of your house. I forget what they call it, but you will NOT escape the PG&E beast.

Your best bet is a small or modest grid-tied system, where you only generate 30-90% of your needs, then PG&E will be happy to let you use their grid as a storage battery. You will save a lot (when factoring in the planned rate hikes)

[russ]

Your best bet is a small or modest grid-tied system, where you only generate 30-90% of your needs, then PG&E will be happy to let you use their grid as a storage battery. You will save a lot (when factoring in the planned rate hikes)

That I agree with 100%. No fun in screwing the utility when it doesn't hurt them even a little bit and costs you big bucks to do so.

[vinniethePVtech]

Vinny bottom line you just chose to pay around 10 times more for electricity for the rest of your life, well maybe 5 to 8 in California. You are not screwing the electric company.

Not really here's the break down. Cost in PV atleast for chinese PV, makes off grid solar lower than GRID Parody. I've done the research. Without inflation,this is the calculated cost that a californian with an 1130sq/ft home pays. I calculated the first 10 years so the 10th year becomes average annual cost for 20 years, basic averaging.

That last calculation to your bottom right is what I would pay over the course of 20 years. $76,026.50 is assumed, this is without inflation whihc as national debt grows so does the cost of a dollar. So what is $76,026.50 now will look like $78,307.30 is is assumed inflation in 20 years rises 3%.

I can purchase all components with tax included (I will round up) $63,000. Now if I was to use high efficiency panels such as sunpower, or schott which are around $1000 per panel pre tax I'm looking at upwards cost of $92,000 system cost assumed. Cost of suntech PV $490 per panel after tax. sunpower or schott $1100 per panel after tax per panel.

Lets do teh break down.

20 year cost of utility $78,307.30
Cost of Off Grid solar $63,000.00
Cost of assumed labor $7800.00

SAVINGS OF $7507.30, this is assumed I could save $10,000 on labor

Then we have batteries. Every one of those batteries is a company owned expense I would take the purchase price write off reciept VS. system depreciation.
Take the initial 5 year system depreciation write down.

System savings after first year of depreciation and write offs. $18,000 assumed.

System cost ($45,000) assumed

Now if i bought the system with high efficiency PV after all write offs and depreciation it would be pointless as it would be right at the cost of grid parody.
I've researched for months its very doable and lower than grid price per watt. Its a win, win. even if I have to replace teh surrette batteries after the 11th year, I write them off.

From a business perspective its smart. Total cost in natural gas/propane use for winter months in 20 years would be $3800 for natural gas.

Now don't get me wrong. I have considered grid tied with a back up generator. So when grid goes down my solar would still make power.