# Solar Power



## prepare_survive_thrive (May 7, 2012)

I have said no knowledge on this subject whatsoever. Trying to read up on it for a switch to off grid but looks like Greek to me. Need suggestions on where to start. How many/size panels do i need to power an average house? And how difficult is upkeep on a battery bank?


----------



## urbanprepping (Feb 21, 2012)

Check out goal zero stuff I have some stuff on there about solar power and some ebooks on off the grid living

And here
http://www.urbanprepping.com/resource-library-3/


----------



## CulexPipiens (Nov 17, 2010)

If you don't know, then you need to do more reading and learning! 

Powering an average house with solar is possible but the first steps usually involve making your house not average. Working to reduce power needs, adding efficiences and doing anything you can to get that number down. 

Once you have an accurate picture of your needs, then, how often is it cloudy and how often is it sunny? Assuming sometimes cloudy, then maybe you'll decide to have your battery bank be big enough to support your power needs for 3 days before getting a recharge. You also should never deplete your batteries lower than 50% capacity so it means that you need batteries sufficient to support your daily need times 6. (3 days with no lower than 50% discharge)

From here you can determine how many panels are needed to recharge this bank in a given amount of time (let's say to recharge it in one day). Now, knowing the amount of panels you need (based on their size) you can back into the charge controller for the battery and the inverter to run your system (unless in the first step you switched everything to highly effecient DC appliances then you might be able to leave out the inverter but that's unlikely).

So if you really want to power an average house, it is doable but you're going to need a lot of cash. The best thing you can do is to get that power need down first. Once that has been achieved you can then start to think about putting a system together that will meet your new reduced needs and for a lot less money.


----------



## CulexPipiens (Nov 17, 2010)

If you want a real quick sticker shock number, try the solar calculator on the left hand side of

http://www.findsolar.com/index.php?page=rightforme

Just find your current electric bill and you should be able to answer the couple of questions and get a ball park number on what a 100% offset system (off grid) may cost you. Then you'll understand why, in my previous most, I emphasized reducing your usage as much as possible as a first step.


----------



## Tex (Oct 31, 2008)

As said, the first step is to lower your power usage to a bare minimum. Most people can't afford to buy enough solar panels to power the average home. Not only will you have to switch to flourescent or LED lighting, but you will need to only have very energy efficient appliances, super insulate your house, and find alternate means to heat or cool your house that don't use much electricity.

It helps if you build your house with all of this in mind, but you may be able to retrofit your house. You will have to pump and heat your own water if you are off grid. Battery storage, charging, and maintenance will need to be considered. You'll need inverters to turn power into AC for household use and probably a generator as a backup battery charger.

It's a huge project. I suggest a subscription to Home Power Magazine. They discuss all of this and more and include articles that explain all of the terminology, some of the electrical code, and have resources to get the most government assistance to minimize your costs. www.homepower.com


----------



## Nadja (Jan 12, 2011)

"Tain't easy, but I have been doing if now for about 16 years. Also pricy unless you really shop around


----------



## Tweto (Nov 26, 2011)

All the green people like solar, but where I live there is only about 230 days a year with sun and in the winter, if it is sunny we only have about 8 hours a day that solar could generate any power. 

Wind power makes more sense, it's windy here 80% of the time. A calm day is rare.

Solar is also very expensive and solar cells have not been proven to last long enough to justify the expense (about 45 years). And another thought, here in farming country we have allot of dust and dirt that gets whipped up in a wind and solar cells will have to be cleaned off continuously to maintain efficiency.

Sorry, just rambling as i write.


----------



## machinist (Jul 4, 2012)

Using the solar calculator given by CulexPipiens, it would cost me twice the value of our house to go 100% solar with our past usage in winter. We have been doing better than that.

As said by several, direct replacement by solar power is impractical, so we must reduce our usage. This is an ongoing process for us. We started where we gained the most first, replacing our electric heat. Added insulation helped a lot, then a wood stove cut our purchased heat to the bone. The $$ savings from that helped fund further savings. 

Clotheslines replaced the electric dryer. A wringer washing machine uses far less power than the old automatic did, and less water, too. All new energy efficient appliances saves on the electric bill and makes going solar more affordable. A summer kitchen reduced our cooling needs in summer, provided a place to can garden produce without cluttering the kitchen, and also a place to start garden seedlings. CFL bulbs helped. Closing off unused rooms helped. We presently use a 120 volt electric water pump, but if we had to go 100% off grid, we would use the hand pump on the back porch and carry water to the toilets for flushing. 

Then, we looked at what we were willing to do without, and what we thought was important enough to use with expensive solar power. We chose to have a refrigerator, a freezer, some fans, lights, and communications, not necessarily in that order. AC is impractical on solar power, so we have worked on ways to keep the house cool otherwise, replacing the roofing with reflective white painted metal. We added reflective infrared foil barrier to the attic, added a porch on the east side, and a sunroom/summer kitchen on the south side. Our elelctric bill has trended steadily down since we started our conservation campaign. 

The bottom line is going to be about 2,000 watts of panels, and the parts alone have cost us over $11K. A significant part of minimizing the amount of solar panels is efficiency of the system. That meant HEAVY gauge wiring, MPPT charge controllers, and running everything we can directly on 12 volts to avoid inverter losses on that much. We spent a lot of money on copper wiring, but you only have to do that ONCE.

Some items come out different than you might expect when you do a cost analysis. Because 12 volt refrigerators are so expensive, it was far cheaper to use a new, more efficient 120 volt fridge and buy a couple more solar panels. It is presently cheaper to keep a 12 volt generator for occassional use on dark winter days than to add greatly to the solar system for those limited periods. 

We are weaning ourselves off the use of the freezer, canning most of our meats and other foods. As time goes by, we will find other ways to cut usage. A solar batch water heater is in our future for summer use only, drained in winter. We keep a kettle on the wood stove when it's going. I have a timer to install on the electric water heater, but we may just go directly to solar on that. 

Solar power is NOT a paying proposition, in our experience. It is simply there so we can have power when there is none from the grid. Life has to change in that circumstance.


----------



## mosquitomountainman (Jan 25, 2010)

Excellent Post machinist! We've lived off-grid for almost ten years now. We love it. For us it was economical ($30,000.00 just to get power to the property) but we wouldn't hook onto the power line now if they ran it under the porch and hooked it up for free. We like the freedom and self-sufficiency. It's stll way less for us than paying a monthly electric bill. 

The key is cutting back on power needs. You are definitely on the right track.

The generator is a good policy too. That's the way most of us on solar power out here do it.


----------



## LincTex (Apr 1, 2011)

mosquitomountainman said:


> The key is cutting back on power needs.


That's the biggest thing. If people bothered to do this on-grid, they would not only have a lower elec bill, but would also have a better idea of how to transition to solar.


----------



## Shiningstone (Jul 31, 2012)

I generated solar power using solar panels and led when I was a kid, worked well but practically it costs a bit . I wish there is a solution for power scarcity.


----------



## Nadja (Jan 12, 2011)

Solar is far cheaper then when I first started. Now, you can find a lot of deals on the net for around $1.00 per watt, especially when buying more then 10 or so. Check into pallet prices and I think you will be amazed.


----------



## prepperware (Jul 28, 2012)

*Bare Minimum system*

Still new to the forum... My 2 cents... 
If you look on ebay, you will see some some people (in Indiana) who are getting "grade B" panels from the manufacturers... these are blemished, cracked but functional cells etc..fully warrented. They are going for 80 cents / watt.. 
Uni-Solar makes flexible panels and I just bought two (PVL-68) 68 watt / 12 volt panels panels for $100 each. ( free shipping too)...These are an older technology panel that they are phasing out, that had cost about $600. In order to use these I will need to get a voltage controller and battery that will cost at least another $200... I don't plan on hard wiring this into the house. It's for emergency use only.
My main purpose is to have a basic solar system to keep basic electronics running (radio, shortwave, HAM, Portable DVD players, etc), recharging batteries ( aa/ aaa/ c/ d) and a 12v car battery or if I can afford it.. a dedicated deep cell battery for solar applications. Led lighting... and with a DC to AC inverter maybe even running a home computer for short amounts of time. 
I admit I'm all over in my thoughts about "how bad" things will get. I figure a crude/simple source of electricity would be better than none at all. It's just insurance that I have "something" if needed.


----------



## BillS (May 30, 2011)

I live in NE Wisconsin. It's 44º N Latitude here. We have a lot of trees to our south. In the winter we'd be lucky to collect enough sunlight to power a lightbulb at night. On the shortest day we have about 8 hours of daylight.


----------



## LincTex (Apr 1, 2011)

BillS said:


> In the winter we'd be lucky to collect enough sunlight to power a light bulb at night.


You would just need a lot more panels. And I really don't think you would need that many to run some 12 volt LED lights.


----------



## AnonyManx (Oct 2, 2012)

In June 2011, we installed a 9.6 kW solar panel system on our roof - 42 SunPower 230 panels (E18) with Enphase micro-inverters. We are grid-tied and have a small-generator agreement with our local utility company. The cost of our system was around $57k (before tax incentives and such); we expect to break even in about 7 or 8 years _at current utility rates._ When energy rates "necessarily skyrocket", our break-even will be sooner. It is important to keep in mind that just because it's a 9.6 kW system, doesn't mean it's actually generating 9.6 kW. I think I've seen the bell-curve top out at 9.1 a couple of times in the past year...

If you want to see some of the generation info for our system, a public page is here: https://enlighten.enphaseenergy.com/public/systems/2wA821115

We did not even seriously consider batteries and off-grid capabilities because of the cost and space involved in the battery banks. Our house is in an all-electric neighborhood, and it's not a small house. We have 2500 sq ft of finished living space, and it comes equipped with 2 HVAC systems, 2 water heaters, electric range, 2 fridges, freezer, laundry equipment, etc. If/when electric rates zoom to where they are oppressive to us, we will go bare-bones on our consumption and tailor our use to what we can generate during the day (on a sunny and temperate day, our meter will actually run backwards for several hours). We can turn off the A/C in the summer and just use a few fans. We can set the thermostat lower in the winter (and use the fireplace to help the upstairs). We can lower or turn off one or both water heaters. As long as we can keep the refrigerators, freezer, and range going, we can survive. Well, and maybe run the washer occasionally...


----------

