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Just for your enlightenment. Version 1.0 is located here.
My Solar landscape Lights V 1.0
Since my first attempt has gone very well. I thought I would consider another venture. I would like to keep the cost to around $500.
So how many lights am I going to light up? Well, I was at my local home depot and picked up a cheap Malibu light kit for only $8. It was an open box sale and appeared to have everything in it. (Actually, I purchased it for the light bulbs!) They want $5 for four replacement bulbs! The kit had 20 in it.) I also have a few light from another similar kit that I did not use. AND, I have the original light in the front of the house. In other words, I could have 50 lights. I will plan for about 40.
If I run my lights for 3 hours in the evening and I hour in the morning. (4 Hours)
The light bulbs use 0.5W of 12VDC. This would be …. 40 bulbs x 0.5W x 4 hours = 80 Watt Hours
80 Watt hours is a good amount of power for lights.
Solar panel size.
Since most controller have selectable nightlight controls, I will use 3 hours of solar insolation. This means in the winter I need to output less number of hours of light and in the summer I can output more number of hours of light.
Panel size would be…. 80 Watt hours / 3 hours = 27 Watts (Usable Power)
What is usable power? If you look at a 30W 12V solar panel power specs you will note that current short circuit is 1.80A and voltage is zero. The panel produces maximum power at 18V with a current of 1.67 Amps. Power = Amps x Voltage. (30W) If you use a regular solar controller, all it really does is connect the solar panel to the battery. This means you are down around 13V. 13V x 1.8 Amps = 23 Watts. You lose a potential 7 Watts. Introduce the MPPT (Maximum Power Point Tracking) Solar controller. They cost more put will get you back most of the 7 Watts you lost.
With the calculations from above I will need a sightly larger then 30Watt panel if I use a regular solar controller.
Battery Pack Size
A good rule of thumb has always been 5 days storage. Another good rule of thumb is never go below 50% of full charge. If I use 80 Watt hours a day. And I need to add about 20% for battery inefficiencies and wire losses… 80 Whrs / 12V = 7 Amp hours. 7 amp hours /50% X 120% x 5 days = 60amp hours.
Now I know what size of components to buy. All I need to do is figure out what to get. The current debate has been a regular controller vs. a MPPT type. I and thinking I will go with the same one I have in the version 1.0 of the landscape lights. It works very well.
To be continued! (component section and justification)
Just to give everyone an example of how much power a CFL (Compact Fluorescent Lamp) uses. My daughter has a small nightlight. The bulb brunt out the other day. My wife comes to me to find out if we have another one. I look at the bulb, C7 7W bulb. (Think Christmas tree bulb) What! you are kidding me, 7 watts for a silly little nightlight bulb! I have a 9W CFL globe lights in my kitchen. Those lights are substantially brighter then a night light. Instead of replacing with an incandescence light bulb I opted for this.
Only cost $4 at Walgreens, and should last forever. Or at least until the kids destroy it.
What does this have to do with solar power? For me, it may have a very big impact. I want to work in the alternative energy industry. If you are reading this, you most likely have a similar desire. You may not act on it, but you have the itch too. Sooooo, how will this election “Change” our alternative outlook?
From his energy speech, the things I like.
• Help create five million new jobs by strategically investing $150 billion over the next ten years to catalyze private efforts to build a clean energy future.
• Within 10 years save more oil than we currently import from the Middle East and Venezuela combined
• Put 1 million Plug‐In Hybrid cars – cars that can get up to 150 miles per gallon – on the road by 2015, cars that we will work to make sure are built here in America
• Ensure 10 percent of our electricity comes from renewable sources by 2012, and 25 percent by 2025
I will focus on plug-in hybrid cars. Why, because I in live in Indiana. Indiana makes cars and car parts. I know, I have worked for my share of them. The problem is that many have closed and moved out of the US. So how will this be any different then before. It very well may not be but, here in Indiana I have little other choice. Now unless someone builds a solar or windmill manufacturing plant near me I will have to look at making parts for plug-in hybrids. I can do that.
Before anyone considers “going solar” you should minimize your energy demands. The biggest energy demand of any household is heating and cooling. So what is “R-value anyway.
R-value is a measure of thermal resistance (K·m²/W) used in the building and construction industry. (wikipedia)
As everyone should know, the bigger the R-value the better. But what is a good standard number? When my house was built R-19 was energy star for the walls and R-38 for the Attic. Now the new house standard have increased. Does this mean my house is not as good anymore? Well, not exactly. The R-value recommendations are made from a cost standpoint. That is to say, R-70 in your attic would be just fine but after R-49 you are just wasting your money. This is more commonly referred to as, point of diminishing returns. Your payback will be longer and longer the more insulation you add. Not a big deal if you plan on staying in your house a long time.
If you can afford to put more R into your home, you will get more money out in energy savings. These saving have been proven to increase the value of your home too. Don’t forget that the feds are will to provide you with a tax credit to boot.