## Designing and building a solar power station

Applied science, crowdsourced...

Astronomy, Chemistry, Earth Sciences, Mathematics & Physics.

### Re: Designing and building a solar power station

If one has access to the grid the addition of solar power is so much easier than our off grid system. Batteries are an option for Jesse, whereas they are the core of an off grid power system like ours. For a grid tied system the batteries will last far longer because they will stay in "float" stage 90% of the time where optimal voltage can be maintained and rarely discharged. In our setup the batteries are cycled daily. Sometimes deeply and sometimes not, but they are constantly being worked. While this is what batteries are designed to do there is a finite number of cycles in any battery. We use flooded lead-acid batteries as are found in nearly every internal combustion vehicle in the world. Ours are just more robust versions with thicker plates. Were we grid tied I would seriously consider Absorbed Glass Mat batteries or even a Tesla power bank.

The nice thing about a grid tied system is the high voltage array possibilities. Some systems can run upwards of 900 volts into pure sine wave grid tied inverters, which must be pure sine wave units to match the grid. Imagine the results of feeding chopped modified square waves into the grid. Most of these inverters can be stacked so that an array can be multiplied over time, and each inverter and solar array adds to the output.

With such a system as Jesse is proposing the size, or gauge, of the cabling can be greatly reduced compared to my off grid setup. Such a system can run at a much higher voltage and thus demand for thick cabeling goes way down. High tension lines carrying power for hundreds of miles are smaller than my main direct current lines, which are double 0 gauge. If I were to switch my system over to a Multiple Power Point Tracking charge controller I too could operate a high voltage array, but such a switch over demands a high upfront investment. Had my broken ankle not consumed our entire summer we were considering exactly this change. Maybe next spring.

Perhaps the most important element in all of this is the transfer switches. If the grid goes down the very last thing a grid tied system should do is backfeed the lines running into the grid system. Workers struggling to repair the grid should never be exposed to an unexpected "live" set of wires from a faulty transfer switch. Spare no expense in this department.

With proper attention to when solar generated power is used the grid can become a minimal component in that big loads can be powered by the solar array.

All in all it seems Jesse has a firm grip on the issues and has the resources to make it happen. After having visited California recently it is apparent that solar power is taking off in a big way. Entire farms are being powered this way, and I am not talking about a two cow 5 acre plot. Huge orchards and vineyards have installed massive systems. Businesses have covered their roofs. As reluctant to change as farmers are the writing is on the wall. Solar just works.

RS
17 years off-grid and counting.

Sleeping in the hen house doesn't make you a chicken.

theropod
RS Donator

Name: Roger
Posts: 7034
Age: 64

Country: USA
Print view this post

### Designing and building a solar power station

So far, the rough plan is this, as far as batteries:

I have the equipment room set aside for them. My initial setup will probably consist of the switch gear, the solar array, and the inverter. When I add batteries, I intend to size the bank for long term off-grid operation.

In other related improvements lately, I got both of those 300 watt mercury vapor dusk to dawn security lamps replaced with motion detecting 36 watt security lights. I'm going to lower the new lights, because the motion sensors will work better when they're not mounted four meters high.

I had a third dusk to dawn security lamp I just replaced with a 38 watt LED version. It was a 70 watt high pressure sodium lamp that produced 4900 lumens. The new LED array produces 4000 lumens for a little more than half the power.

Not as much of a power savings as I like, but I can light an entire interior room for that 32 watts I just saved.

Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.

The_Metatron
Moderator

Name: Jesse
Posts: 19907
Age: 54

Country: United States
Print view this post

### Designing and building a solar power station

I've started a small scale test for September. I'm going to run my mobile phone and my tablet entirely off of grid power. They use so little energy, that really isn't the point. What I want to exercise is the concept of keeping my little 28 Wh power tank topped off every day with my solar array. Since I have multiple USB ports on the array, I can charge one other device at the same time as my power tank.

For example, my power tank is fully charged right now. So, I have both of our iPhones charging with it. They have room in their batteries, the sun is shining, and we can sit on the terrace with them while they charge. I want to sharpen the habit of collecting all the watt-hours I can use and use the ones I'm collecting.

Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.

The_Metatron
Moderator

Name: Jesse
Posts: 19907
Age: 54

Country: United States
Print view this post

### Re: Designing and building a solar power station

If someone hasn't already mentioned it, an attic fan is incredibly useful and can cut down on cooling bills, especially in areas that cool off significantly at night. [Here in central texas, when it's really hot, it can still be upwards of 90 degrees at midnight] They can completely change the air in your house in a few minutes, great for cooling off or helping after you've had another cooking disaster. They're not as useful where I live now, but I still have one, there are still plenty of days they're great and I'd always rather have fresh air than AC if possible, it's just not that possible around here where it's hot and humid way the fuck too often.
“When you're born into this world, you're given a ticket to the freak show. If you're born in America you get a front row seat.”
-George Carlin, who died 2008. Ha, now we have human centipedes running the place

crank
RS Donator

Name: Sick & Tired
Posts: 10362
Age: 3

Country: 2nd miasma on the left
Print view this post

### Designing and building a solar power station

crank wrote:If someone hasn't already mentioned it, an attic fan is incredibly useful and can cut down on cooling bills, especially in areas that cool off significantly at night. [Here in central texas, when it's really hot, it can still be upwards of 90 degrees at midnight] They can completely change the air in your house in a few minutes, great for cooling off or helping after you've had another cooking disaster. They're not as useful where I live now, but I still have one, there are still plenty of days they're great and I'd always rather have fresh air than AC if possible, it's just not that possible around here where it's hot and humid way the fuck too often.

I cool the house that way at night, but with a fan in a window. An attic model would work better and quieter.

Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.

The_Metatron
Moderator

Name: Jesse
Posts: 19907
Age: 54

Country: United States
Print view this post

### Re: Designing and building a solar power station

Well, I don't even have an attic, so mine to is struck in a window also;) Ya gotta make do.
“When you're born into this world, you're given a ticket to the freak show. If you're born in America you get a front row seat.”
-George Carlin, who died 2008. Ha, now we have human centipedes running the place

crank
RS Donator

Name: Sick & Tired
Posts: 10362
Age: 3

Country: 2nd miasma on the left
Print view this post

### Re: Designing and building a solar power station

We have a solar power (stand alone) attic fan. It obviously doesn't work at night, but it makes a big difference in the daytime. It is thermostatically controlled so it doesn't pump heat out in the winter, and only turns on above 85° F.

RS
17 years off-grid and counting.

Sleeping in the hen house doesn't make you a chicken.

theropod
RS Donator

Name: Roger
Posts: 7034
Age: 64

Country: USA
Print view this post

### Re: Designing and building a solar power station

That sounds more like an exhaust fan. Is your attic have a vent into the house? 'Attic fan', at least in my experience, implies something typically mounted in the ceiling in a central area, blowing interior house air into the attic and out vents in the gables or soffit vents or wherever. Limiting an attic fan to daytime use would really be a severe limitation to its usefulness.
“When you're born into this world, you're given a ticket to the freak show. If you're born in America you get a front row seat.”
-George Carlin, who died 2008. Ha, now we have human centipedes running the place

crank
RS Donator

Name: Sick & Tired
Posts: 10362
Age: 3

Country: 2nd miasma on the left
Print view this post

### Re: Designing and building a solar power station

crank wrote:That sounds more like an exhaust fan. Is your attic have a vent into the house? 'Attic fan', at least in my experience, implies something typically mounted in the ceiling in a central area, blowing interior house air into the attic and out vents in the gables or soffit vents or wherever. Limiting an attic fan to daytime use would really be a severe limitation to its usefulness.

Oh, OK. Limited usefulness or not, it helps cool our house. Having a steel roof the daytime temperatures in the attic go seriously high. The manufacturer markets the device as an attic fan. It vents hot air from the attic.

RS
17 years off-grid and counting.

Sleeping in the hen house doesn't make you a chicken.

theropod
RS Donator

Name: Roger
Posts: 7034
Age: 64

Country: USA
Print view this post

### Re: Designing and building a solar power station

I've been looking at the valley where I can put my array. It's 09:37.

Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.

The_Metatron
Moderator

Name: Jesse
Posts: 19907
Age: 54

Country: United States
Print view this post

### Re: Designing and building a solar power station

Trying to map out my array plan. Fuck, that's no easy thing when you have obstacles to consider. I have to plan a layout, then play it through the year to see where the shadows aren't.

Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.

The_Metatron
Moderator

Name: Jesse
Posts: 19907
Age: 54

Country: United States
Print view this post

### Re: Designing and building a solar power station

Some steel T posts, or sturdy wooden stakes, will serve you well here. Five should suffice. On the winter solstice drive three of them. One at the center of where you expect the array to reside and align a second on a line toward the point the sun rises, and repeat with the setting point. Keeping the center post repeat this for the summer solstice. Dividing the distance between the rising and setting solstice points will provide the yearly average exposure maximums. This will give you more information than any other resource about your site. Of course this depends on the sun shining on those two days, or a few either side. In your region the winter event could be obscured for weeks. Perhaps another means to obtain these angles can be found.

RS
17 years off-grid and counting.

Sleeping in the hen house doesn't make you a chicken.

theropod
RS Donator

Name: Roger
Posts: 7034
Age: 64

Country: USA
Print view this post

### Re: Designing and building a solar power station

Star Walk to the rescue. I can march the sun through any date and time I want, and see it's azimuth/elevation.

Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.

The_Metatron
Moderator

Name: Jesse
Posts: 19907
Age: 54

Country: United States
Print view this post

### Re: Designing and building a solar power station

The_Metatron wrote:Star Walk to the rescue. I can march the sun through any date and time I want, and see it's azimuth/elevation.

Sent from my iPad using Tapatalk

In the words of the Goblin King, "That'll do it."

RS
17 years off-grid and counting.

Sleeping in the hen house doesn't make you a chicken.

theropod
RS Donator

Name: Roger
Posts: 7034
Age: 64

Country: USA
Print view this post

### Re: Designing and building a solar power station

theropod wrote:
crank wrote:That sounds more like an exhaust fan. Is your attic have a vent into the house? 'Attic fan', at least in my experience, implies something typically mounted in the ceiling in a central area, blowing interior house air into the attic and out vents in the gables or soffit vents or wherever. Limiting an attic fan to daytime use would really be a severe limitation to its usefulness.

Oh, OK. Limited usefulness or not, it helps cool our house. Having a steel roof the daytime temperatures in the attic go seriously high. The manufacturer markets the device as an attic fan. It vents hot air from the attic.

RS

It limits it's usefulness if it was an attic fan, it's fine for an exhaust fan. The terms are awfully loose, no big deal, i was trying ascertain if it was one of those fans that's meant to keep the attic cool, or the type that are more directly meant to change the air in your house. Do they call the latter something different?
“When you're born into this world, you're given a ticket to the freak show. If you're born in America you get a front row seat.”
-George Carlin, who died 2008. Ha, now we have human centipedes running the place

crank
RS Donator

Name: Sick & Tired
Posts: 10362
Age: 3

Country: 2nd miasma on the left
Print view this post

### Re: Designing and building a solar power station

The_Metatron wrote:Star Walk to the rescue. I can march the sun through any date and time I want, and see it's azimuth/elevation.

Sent from my iPad using Tapatalk

Star Walk? Is that a parochial version of Star Trek?
“When you're born into this world, you're given a ticket to the freak show. If you're born in America you get a front row seat.”
-George Carlin, who died 2008. Ha, now we have human centipedes running the place

crank
RS Donator

Name: Sick & Tired
Posts: 10362
Age: 3

Country: 2nd miasma on the left
Print view this post

### Re: Designing and building a solar power station

Nah, a sky atlas app: Star Walk HD - Night Sky Map by Vito Technology Inc.
https://itunes.apple.com/us/app/star-wa ... 86802?mt=8

Sent from my iPad using Tapatalk
I AM Skepdickus!

Check out Hack's blog, too. He writes good.

The_Metatron
Moderator

Name: Jesse
Posts: 19907
Age: 54

Country: United States
Print view this post

### Re: Designing and building a solar power station

The thing is our summer nights do not cool off all that much, but humidity does go up. If a fan pulled in that moist air it could saturate the insulation, and lower its R value until dried again the next day. Some mornings here the dew is so intense it looks like a heavy rain has passed, and I don't like the idea of my attic being a home for that. Years ago the fans that circulated air through the whole house and out the attic were common in the southern US. Now not so much. When the heat index soars past 100° F, which is common here, there is no cool air to draw into the house. This means the function of exhausting the attic is of more importance than attempting to use extraordinarily hot outside air as a cooling force. All that does is create a hair dryer effect where electricity is being burned to exchange this inside hot air for that outside hot air. If we can lower the attic temperature, which our stand alone solar fan does, the air conditioning doesn't have to work as hard. Call it what you like, but our fan works in our semi tropical summers better than the whole house ventilation fans of old. Our air conditioning system is as much a humidity fighter as a cooling agent.

RS
17 years off-grid and counting.

Sleeping in the hen house doesn't make you a chicken.

theropod
RS Donator

Name: Roger
Posts: 7034
Age: 64

Country: USA
Print view this post

### Re: Designing and building a solar power station

theropod wrote:The thing is our summer nights do not cool off all that much, but humidity does go up. If a fan pulled in that moist air it could saturate the insulation, and lower its R value until dried again the next day. Some mornings here the dew is so intense it looks like a heavy rain has passed, and I don't like the idea of my attic being a home for that. Years ago the fans that circulated air through the whole house and out the attic were common in the southern US. Now not so much. When the heat index soars past 100° F, which is common here, there is no cool air to draw into the house. This means the function of exhausting the attic is of more importance than attempting to use extraordinarily hot outside air as a cooling force. All that does is create a hair dryer effect where electricity is being burned to exchange this inside hot air for that outside hot air. If we can lower the attic temperature, which our stand alone solar fan does, the air conditioning doesn't have to work as hard. Call it what you like, but our fan works in our semi tropical summers better than the whole house ventilation fans of old. Our air conditioning system is as much a humidity fighter as a cooling agent.

RS

I'm not trying to argue, just figure out what's what. I'm not sure where you are but it can't be too different from where I am. As I said when I first mentioned the fan, it isn't useful a lot of the time, not like in southern California [where I used to live and got turned on to attic fans] which is about as good as it gets for antic fans. But there's more than enough days here in C. Texas that it makes having one stuck in a window more than worth the trouble. I don't even have an attic. It's useless 100% of the days/nights from about May to October roughly. But the days when it's hot during the day and cool off quickly in the evening, I love having it, it's just much much nicer having fresh air and the doors and windows open.

I absolutely hate humidity, when it's hot, it makes you that much more miserable, plus I sweat like crazy. And then the way it fucks with trying to get the right temperature in your house when it's slightly cool but really humid. Inside a home it's always warmer than outside, especially if ya got a lot of electronics running. And it gets really horribly warm/humid inside, but the only way to cool the air down is to make it really cold because the air is really humid but cool so you have to get the air pretty cold to dry it out. It drives me crazy having to be out in whether like that, if you're not at all active, you can get cold if there is even a slight breeze, but it takes very little activity to warm up and get hot and start sweating profusely, if you're a sweater like I am.
“When you're born into this world, you're given a ticket to the freak show. If you're born in America you get a front row seat.”
-George Carlin, who died 2008. Ha, now we have human centipedes running the place

crank
RS Donator

Name: Sick & Tired
Posts: 10362
Age: 3

Country: 2nd miasma on the left
Print view this post

### Re: Designing and building a solar power station

We had an attic fan (bringing air through the house and out the attic) when we first moved in. It was really quite useful on a hot day, but too noisy to run at night. We took it out when we put in new air conditioning because we needed the space for additional ductwork for the new extension.

Until we figure out how to store enough energy to run A/Cs all day going completely off-grid in Florida is a non-starter. For me, anyway. I have no idea how anyone tolerated living here in pre-aircon days.
A man who carries a cat by the tail learns something he can learn in no other way. - Mark Twain
The sky is falling! The sky is falling! - Chicken Little
I never go without my dinner. No one ever does, except vegetarians and people like that - Oscar Wilde

laklak
RS Donator

Name: Florida Man
Posts: 17021
Age: 63

Country: The Great Satan
Print view this post

PreviousNext