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This is in reference to HI Someday's question in a different post... Hopefully this is helpful for others as well....
When calculating solar watts everything is always for a 1 hour period. So, a 250watt panel may produce 250watts in one hour. On average, we 3-4 sun hours per day here on Big Island. A 250 watt panel will actually produce about 200 watts at peak sun. When calcualting , weather must be considered. Production goes down greatly with clouds. The first thing we do when sizing is try to eliminate any inefficient appliances. Reducing your load is the first important step. When doing grid ties... We use approx ten dollars a month from your helco bill per panel. Example: a 200 dollar a month helco bill will take 20 panels.
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808-969-1133
Http://www.builditgreen808.com
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250 watts (.25 kw) for 1 hour produces 250 watt-hours (.25 kwh).
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We generally use 1-2kwh/day. If I ever buy/build another house in Puna it will be Solar, I think.
Me ka ha`aha`a,
Mike
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We are not on the island yet, so very difficult to calculate what our needs will be. On the mainland, we have to run AC, so a calculation done on current use will not pertain to usage there. Is there a general "rule of thumb" for how large of a system that is required for a family of four? We know we will have to re-think all the the waste on our ends (like leaving TV on when nobody in room, electric clocks, etc.). Still, do not know if there is a *general* configuration/size we should be thinking about to meet our needs. Thank you.
Best wishes
Best wishes
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Buy a "Kill-a-Watt" from your local Home Depot. Use it to measure the "actual" KWh/day for your critical appliances. Size the PV array to at least 2-4x that amount; the scale factor is roughly "available sun-hours/day" (less sun, bigger array).
For the battery plant, multiply daily consumption by "number of dark days in a row", then multiply again by about 5 (wet lead-acid batteries last longer if usage is kept to about 20% of capacity; other technologies behave differently).
Size the inverter to handle the biggest surge load, which is anything with a motor (eg, the fridge). Example: your house may idle at 100W, but you'll probably need a 2500W inverter to start the fridge.
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Anybody familiar to the Unisolar thin film for metal roofs? Are they worth it as far as price, wind resistance, wattage? Is there a better thin film? Thanks in advance for your knowledge.
Community begins with Aloha
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Thin film solar panels are not very good. Their output is lower than silicon and with constant weathering will deteriorate quickly.
I used a few once, replaced them the next year with a real solar panel.
here is a rundown of just how "fine" amorphous panels are
http://www.energymatters.com.au/renewabl...alline.php
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Thank you. I was wondering about the durability, now I know.
Community begins with Aloha
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Aloha, I can't emphasize enough how important it is to work with someone who truly cares about how YOU want to live-what your actual power needs are, not a suspected or generalized power need assessment. We did not want to change our lifestyle and we wanted to have a little extra available as we have frequent guests. Mikale at Build It Green in Hilo created a system that we have lived with and are delighted with. During the power outage in our area, our home was a haven and provided innumerable showers, laundry loads, and etc. We never fired up our generator...our PV panels and batteries did their job and did it well. Have a great day!
Jan
Jan
