# Simulation software for alternative energy setups



## pengyou (Jun 22, 2009)

Do any of you "mix" your alternative energy sources? I am looking at some land now in an area that has brisk wind after sunset and on cloudy/rainy days- enough to be useful - and lots of sunshine 350 days a year. I know that most people who use solar energy just pop pv cells up somewhere, but lots of batteries, a backup generator and enjoy. I was wondering, if I bought a small wind turbine to be used during the evening, used pv panels in the daytime, would I be able to get away with using fewer batteries? The idea is that the turbine would be able to provide enough juice for the evening and stormy days, the pv panels would provide the power for the day, and there would still be a backup generator - though I am thinking, if I pay attention to the weather forecast and think ahead, I can buy a smaller generator because I have the turbine as one backup. It is likely to be more expensive than just a single solar energy source but I am willing to pay some extra to have the redundant backup. 

Ideas?

Also, is there some software that would let me simulate light and wind conditions for my home, given some parameters?


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## MichaelK! (Oct 22, 2010)

Don't skimp on the batteries. It's really false economy if you try to make to with less, and then find yourself draining them down too much. If you never drain batteries more than 10-20% of their capacity, their lives will be measured in years. Drain them repeatedly and their lifespan will be measured in weeks.

Then of course there's the disconnect between what you think the wind is, and what it really takes to make SIGNIFICANT power. I'm not saying that wind generators don't work. It's just that the wind really, really needs to high before they produce anything close to their rating. Below about 7-10 miles per hour, the wind will generate NO power, while a 10-15 mile per hour wind most likely will only produce 1/10 what the mill is rated for.


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## Jim-mi (May 15, 2002)

No idea where your located . . . . . .Have you consulted wind maps for your area . .??

You raise a red flag when you say "purchase a SMALL wind turbine".
All those **small** cheap wind turbines perform dismally in lower wind areas.
They require a lot more wind to get any kind of output......
They might be spinning but the out put is very low.
Those **SMALL** turbines often require 25 to 30 mph for any kind of out put.
Does your area have that much day to day wind . . . .????


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## wy_white_wolf (Oct 14, 2004)

Sounds like someones wants to commit murder on a set of batteries. Undersizing the battery bank only shortens it's life.

Because of the chemisty involved, deep cycle batteries should only be discharged a maximum of 20% a day. That also gives you 2.5 days atonomy before you get to 50% discharged which is the maximum you can discharge before damage starts to occure.

Now having both wind and solar can easily put the batteries in a 2 cycle a day situation. Granted each cycle will be shallower. Undersizing the bank just sets it so the cycles are not shallower then the should be and your battery bank will last less then 1/2 time it should if it was properly sized to the load. 

Also then each day that the 2 charge cycles do not occure you overdischarge the battery shortening the live even more. 

Using a generator to make up for the undersize situation just adds to the fuel expense which can run more than keeping everything tied to the grid.

WWW


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## pengyou (Jun 22, 2009)

Thanks! Now I have a point of reference with which to study. I am shopping for land in Arizona now - northeast to east central.


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## MichaelK! (Oct 22, 2010)

After purchasing your land, I'd get a portable weather station. Something like this for example.

http://www.amazon.com/AcuRite-01036...id=1422548603&sr=8-4&keywords=weather+station 

I mounted one like this on a fence about 100 feet from my cabin, and it has been a very valuable measuring tool. Especially for monitoring minimum temperatures when I'm asleep or away. 

What I've found is that in only takes about a 10 MPH wind to say "enough, let's go inside", and from studying output charts, 10 MPH wind will generate next to no power.

But, since you're shopping in Arizona, you'll be guarrantied about 300 sunny days per year, so panels will serve you well. On the few winter days when it's stormy and blewn, you can finally get a few watts out of a mill. But, even with just 10% capacity, a small mill might put out 3-4 amps, which is better than nothing. Better than what a panel might put out with moonlight.


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