Off Grid Home electric therory

You shouldn't draw down your battery's more than 50% of rated battery capicity or it severely shortens your battery cycle life. That's about 1.5kw/hr on your exisitng battery's.

You can add any number of PV's to your system as your CC will limit the charge to your battery's.

Tracking the sun will also produce the highest return from your PV's vs a fixed mount. Not hard to make your own sun tracking system out of pipe and a couple of bearings.

I just checked on generating to the AZ utility. Excess power has to be fed thru there auto switch box then metered back to you. You then subtract energy generated from enregy used and any excess gets credited to your current bill at retail rates with the excess generated carried over to the next bill cycle. If at the end of the year you have generated more than you used then the meter is reset and you LOOSE the excess credit or your just giving the utility the excess power.

Not only that but you still have to pay all of the "other" misc monthly fees. That means on my past $85mth bill, I would get a credit for $35 for the power used and still would owe $50 for the "fee's".

Ya right, like I'm gonna pay to supply my utility with "free" power.

T_Bone

Years ago a consulting engineer said the pinwheel was nice if you enjoyed having a big pinwheel, but PV was better for energy and you had to plan on working on the pinwheel up on top the tower once a year at least.

Gerald J.

As far as "consulting engineers" go, some are very good, and some are functional idiots. I've met and worked with both varieties.

In regard to wattage? Most people who get serious do all they can to make their home efficient first. I got mine down from 700 KWH per month down to 280 KWH before changing over.

I'm in New York with some of the poorest annual sunshine for the U.S. I have 5400 watts in solar panels and twin full-wave Outback inverters. We make a little more per year, then we use. But, we are grid-tied with a battery bank. If we did not have the grid-tie - we'd lose half the electricity we make. Right now - my panels are making 5700 watts (they're over-producing). Obviously, I can't use all that power right now. So, if the power company wasn't buying it, it would all be wasted. No one has invented a way to save excess power yet at the home - although I've seen some convoluted ideas. I've got 5400 watts of Kyocera 175GT panels. They give us an average of 4000 KW-hours per year. If we lived out west - AZ or CO - we'd be making 7-8000 KW-hours per year with the same array. Now, if we were totally off-grid - we couldn't make near what we're making - because -either we'd have less panels - or - we'd have more and waste all the excess power. If you are trying to figure losses - remember you've got several. The panels usually do not put out what they are rated for - even in bright sun. The inverter has loss, and the battery bank has loss. Then, controllers have different levels of efficiency. Then - the worse part - is the loss from not being able to store excess power when you make it.

The Batteries contain about 6x250x12 = 18 kWhrs

Your inverter efficiency I am guessing to be about 80%, and therefore

18 kWhrs * .80 = 14,4 kWhrs

Personally unless you are real frugal with your electricity I think that you are underpowered (wind generation capablity) and under batteried.

Good luck! HTH

Cliff (VA)

A 1 kilowatt Solar System, about 10-12 solar modules, requires about 100 square feet of installation area. Double the square feet area, if you are using thin film technology modules. This technology represents about 10% of all modules sold.

A sunny location (i.e. Los Angeles, USA) receives approximately 5.5 hours of sunlight on average throughout the year.

Monthly average residential consumption of electricity in the United States in 1999 was 866 kilowatt hours. (Source: US DOE)

A 1 kilowatt home solar system installed costs about US$9000

Gerald J.