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I need 300 killowatts per month for household

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Posted by Tim Thomson on July 6, 2005, 1:00 pm
How many 15 watt/12 volt panels would it take to produce 300 k watts per
How many batterries would be recommened for 300 k watts divided by 30 or
10 k watts a day? About five hours of sunlight per day.

Posted by Steve Spence on July 6, 2005, 3:08 pm
That would probably be 300 kWh / month.

the lower wattage panels are much more expensive per watt than those
100watts and up, but lets run the numbers.

Lets say that 300 kWh's / comes out to 10 kWh's per day, and that you do
have 5 full sun hours a day (are you in CA?).

10 kWh / 5h = 2 kW. You need a 2 kW array (round numbers not taking into
effect a 30% inefficiency fudge factor).

2 kW / 15 watt = 134 15w panels.

Steve Spence
Dir., Green Trust

Contributing Editor

Tim Thomson wrote:

Posted by DJ on July 6, 2005, 3:33 pm

Steve Spence wrote:

Two kilowatts is about the "rule of thumb" for a comfortable off grid
home, yep.


Posted by Tim Thomson on July 6, 2005, 7:11 pm
 Steve Spence wrote:

I am not in CA. I am at 50 north by 115 west..... Crows Nest Pass Alberta
I was just thinking about starting a small system. I have easy acsses to the
15 watt and now it looks like 30 watt panels.
I know they are pricey but I have been playing with 3-15 watt panels and was
just wondering. The 15 watt panels are about 20 inches by four feet, what size
are the 100 watt panels?

How many 12 volt batts does it take to store say 5 kva. I allready have an
inverter ( Brutus true sinewave 12 volt)
I could probably cut my needs in half by replacing my fridge with a natural
gas one if they make one that is. I could also get rid of the elctric dryer.
At present I am using the old incadesent lights. I still have a few wall warts
to get rid of etc..... I live in a wind belt, we have hundreds of those 3.2
mega watt wind turbines here but they will not allow a small one (400 watt) to
be installed at my house.
I am also looking at NG gas genney for back up.

Posted by Steve Spence on July 6, 2005, 7:30 pm
 According to http://www.e-marine-inc.com/articles/images/canadaiso.jpg  
you are looking at 2 full sun hours per day, not 5, so you will have to
at least double the number of panels. 5kva(h) of batteries might look
like 8 trojan t105's, 2 series x 4 parallel. That would give you 900ah,
or 450ah usable. You really need to rethink this.

Steve Spence
Dir., Green Trust,   http://www.green-trust.org
Contributing Editor, http://www.off-grid.net

Tim Thomson wrote:

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