Living off the Grid, Part II: Northern Exposure

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For instance, I have a stereo system that I know is going to run for a couple of hours each day. I also have a large television set, VCR, etc. I just added them up. I found that those appliances, plus a few others, plus lighting and water pumping from my well demanded approximately 1.5 to 2 kilowatt-hours each day. I even did some figuring for different times of the year. In the summer, you may use different appliances; winter requires more lighting, etc.

Actually, one of the biggest hogs is our coffeemaker. Any heating element uses a lot of power. But it's only on five minutes a day when we make breakfast in the morning, so it's overall impact is very small. Richard [Gottlieb] then helped me to design a system of 12 solar modules working together. Each module generates about 50 watts of DC electricity for every hour of direct sunlight it's exposed to. Fifty times 12 equals 600 watts. That's the amount of power my solar system produces for each hour of direct sunlight.

During the spring, summer, and fall, I'll probably be generating 2.5 to 3 kilowatt-hours each day-more power than I need. But during the worst part of winter, I might only get 1 kilowatt-hour, so I may have to run the generator once a week to top up the battery bank.

MOTHER:What happens on a cloudy day? Do you break even if you use no electricity?

A $15.000 GRID EXTENSION

"I was confronted with the possibility of not being able to build on a beautiful site simply because I couldn't afford to service it. I needed some options."

System Layout

Kip decided to store all his power equipment together in the basement. Batteries are placed on a heavy wooden skid both to protect them from any water on the floor and to allow proper air circulation. The powercenter, Inverter, AC- and DC- load centers are all rack mounted for ease of access. During construction, Kip is content to run the generator in the open basement and keep the batteries uncovered. When the house is occupied and the basement enclosed, the generator will have to be housed in an external shed where its fumes will not be a hazard and the battery bank covered to prevent accidental discharged from dropped metal, tools etc..

The diagram at below shows basic wire configuration as well as series and parallel arrangements in the battery bank and solar array. Kips system has two sets of six panels, wired identically and connected to the power center through two junction boxes and 2X #6 THHN wire.

The most convenient power for Kips home is 120 volt AC, fed to the AC-load center and home outlets through the Inverter. He has some specific DC needs, however, such as his DC-well water pump which can be supplied directly from the powercenter. A 24-volt DC to 12-volt DC converter and DC load center is required.

See "How Kip Did It." for a guide to wire sizes and connections .
Scott MacNeill

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