Any opinions/suggestions on my emergency power setup?

BB. · May 2017

Balancing your array can be expensive if a gust of wind pops up. The panels are thin tempered glass and will shatter 100% across a whole panel. Leaving you with a modern art piece.

Some sort of wind resistant mount quickly.

- Bill

westbranch · May 2017

What brand of fasteners /clamps did you use to clamp the panels down to the uni-strut?

bill von novak · May 2017

BB. said:

Balancing your array can be expensive if a gust of wind pops up. The panels are thin tempered glass and will shatter 100% across a whole panel. Leaving you with a modern art piece.

And with a flying battering ram until it finds a new home.

I second the above - permanent mount NOW.

mcgivor · May 2017

Yes anchor down, thats a pretty good sail.
I take it you are going to mount the CC on a wall.

St8kout · May 2017

Yeah, I'm real familiar with the high winds here. Just last month we had 85 mph winds that took down dozens of power lines across the city. A Cat 1 hurricane rating starts at 74 mph, so we had a Vegas hurricane for a few days.

That is why I anchored the 2x4 support in some 30 inches of concrete. The aluminum pole is pinched in between, resting on an 8"x1/2" bolt, which I have to loosen to see-saw the array. During the winter season the other end of the pole would be on the ground, but now that summer is almost here I had to raise it up according to the angle of the sun.

You might have noticed the wall in the background. It goes all the way around the yard and is some 7' high on the west side, where most our winds come from, and if there is another severe wind storm warning I can lock the array horizontally so the wind resistance is minimal, an advantage of being able to see-saw it.

As for the Unistrut mounting hardware, Renogy makes the solar panel hardware fasteners, (which you can find on Amazon but were on sale on Renogy's website), but the 'nut' part of it is proprietary for their own brand of roof rails. When I explained to the nice saleslady at Lowes that I needed to use these Renogy fasteners with the Unistrut bars and nuts, she quickly fixed me up with the appropriate sized screws. I've seen some youtube videos where they just used bolts and large washers to fasten panels to Unistrut. I didn't particularly care for that solution.

https://www.amazon.com/Renogy-1-38in-Clamp-Surface-Mounting/dp/B00WFKE2HK/ref=cm_rdp_product

https://www.renogy.com/accessories/mounts/rail-mounts/

St8kout · May 2017

Things I would do differently if I had to do it all over again:

-The 12/24 volt panels are not the best bang for the buck. At the time nobody locally was selling the much cheaper grid-tie panels, and the outrageous shipping costs offset the cheaper price, unless you are buying a whole pallet. Since then, local individuals on Craigslist are buying them in bulk, and selling them new in box as a side business. I could have had almost three times the wattage for what I paid for my four 160 watt panels.

-Circuit breakers instead of fuses for solar panels and charge controller. DC breakers are about the same price as inline fuses, and replacement fuses are not only impossible to find locally, but I saw prices as high as $8.99 per fuse online. So why bother when you can get a DC breaker for about $12, plus they act as an on/off switch. The inline fuses have warnings against disconnecting them under load. I ended up buying the Midnight Solar breakers and box anyway and using them instead of the inline fuses I wasted money on.

Lumisol · May 2017

If the air temp in the shade is 120, the surface of the panels in the sun will be closer to 180 to 190. You can fry an egg on them.
You need to secure the panels better than just proping them on a stack of blocks or the first 40 mph gust will launch them into the neighbors yard.
I think your realtor has no idea what he or she is talking about, pools are dug with a backhoe not explosives. Lol

Lumisol · May 2017

Photowhit said:

St8kout said:
Photowhit: Yeah, I figured it might be pushing it and when we get closer to summer I might buy more panels. I planned to see just how much drain there would be on the batteries once it's up and running and go from there.

No you are not "pushing it", it's not realistic at all!

I've been there and done that, when it comes to running and air conditioner on a small system. With a well insulated cabin, 6" walls, built in the shade, I was able to run 5 hours+/- on battery system of 4 golfcart batteries with about 230ah at 24 volts and 1000 watts of array, I increased the system to about 1600 watt array to give me more daytime running. I also shut down the fridge to give me more running time on some summers.

St8kout said:
Bill Novak: I found this solar calc website, http://pvwatts.nrel.gov and you can plug in different figures to see the result. On a yearly basis, it shows a 46% increase with 2 axis tracking over a fixed roof mount. Am I missing something? I used .6Kw for panel output.
Fixed mount = 1041KWh
2 axis tracking = 1523 KWh
1523-1041=482
482/1041=.463 x 100= 46.3% increase.
If I'm not mistaken I would need to add 277W worth of panels to a fixed mount to get the same power as 2-axis tracking.

The site is for grid tied systems, Off grid systems don't work the same.

Off grid systems must have greater losses as they must fully charge a battery regularly. Think of the grid as a battery bank that is never full. It will take the energy if it can be produced. If you do a grid tied system it is accurate. In general you need about 3x the amount of array to produce as much usable electric in an off grid system. I can expand on this later. but energy going into the grid losses about 1-3% going through the inverter. In an off grid system, using stored energy the losses are roughly 50% through the charge controller, battery, wiring and inverter.

You have used the figure of .6 kw for output. Realistically your 650 watt array will produce about 75% of it's panel rating, or about 650x.75= 487.5 watts, though likely even less with your high panel temperatures. You might be able to find the NOCT (Normal Operating Cell Temperature) values for your panels.

That looks like the same shed we have behind our side wall in the backyard. They are nice places to store the lawnmower and other equipment.

mcgivor · May 2017

That looks like the same shed we have behind our side wall in the backyard. They are nice places to store the lawnmower and other equipment.

What the #@&% ! That's below the belt, it's a small home, not a shed for storing gardening paraphernalia.

nickdearing88 · May 2017

mcgivor said:

That looks like the same shed we have behind our side wall in the backyard. They are nice places to store the lawnmower and other equipment.

What the #@&% ! That's below the belt, it's a small home, not a shed for storing gardening paraphernalia.

I was going to say.....it looks way too nice to be a garden shed.

BB. · May 2017

Please folks... Keep it friendly. It works very well for him. Everyone has to makes choices in life.

-Bill

Lumisol · May 2017

No offense intended. I am sure it would work fine for both applications as well as a few more such as a separate office space, etc.
My wife considered using one of Lowe's sheds as a tiny home before the tiny home thing was a thing, although she never actually did it.
I can see the value in that.
I bet the pine needles landing on the roof at night sound fantastic, I used to love that sound in our cabin in Payson as a kid.

St8kout · May 2017

Lumisol said:

If the air temp in the shade is 120, the surface of the panels in the sun will be closer to 180 to 190. You can fry an egg on them.
You need to secure the panels better than just proping them on a stack of blocks or the first 40 mph gust will launch them into the neighbors yard.
I think your realtor has no idea what he or she is talking about, pools are dug with a backhoe not explosives. Lol

Go back and read my post about how it IS anchored down.

And we're talking Las Vegas ground. Forget using a shovel, you need some kind of pickax here. "If you have dug in your back yard, you’ve encountered this carbon as caliche, a brutally hard, white deposit of calcium carbonate." https://lasvegassun.com/news/2009/mar/03/its-dirty-job/

So it's not hard to believe they've used explosives, as I said, in NEW subdivisions. They certainly would not use them near existing houses. You might remember there was a huge housing boom in Vegas back in the 80's. I'm surrounded by a thousand houses all built during that time. Our subdivision was built in 1985.

Oh, not sure why someone's storage shed was posted, but it's NOT mine, just in case you're wondering:)

The system is powering my A/C just fine during the day. I have not run it at night because I don't want to drain the batteries. The theoretical calculations says I can run it 10 hours just on the battery bank before it drains to 50%. But of course in the real world things are not always so. I have noticed that the Controller meter shows it's pulling some 35-40 watts more from the panels than my A/C is using according to my kill-a-watt meter. So I assume that's about a +10% loss in Inverter/Controller efficiency. (The A/C pulls between 350 and 400 when the compressor is running.) My four 160 watt panels seem to be adequate for my purpose, but I may add more at a later time.

bill von novak · May 2017

St8kout said:

you need some kind of pickax here. "If you have dug in your back yard, you’ve encountered this carbon as caliche, a brutally hard, white deposit of calcium carbonate."

FYI here in San Diego there's something commonly used that's called a San Angelo bar (non-PC name is Jose bar) which is a 20 lb steel bar with a sharp point on one side and a narrow chisel point on the other. You raise it as high as you can and slam it into the ground as hard as you can; it fractures the dirt and you can then use the chisel point to pry rocks and pieces of dirt out of the hole.

St8kout · May 2017

bill von novak said:

St8kout said:

you need some kind of pickax here. "If you have dug in your back yard, you’ve encountered this carbon as caliche, a brutally hard, white deposit of calcium carbonate."

FYI here in San Diego there's something commonly used that's called a San Angelo bar (non-PC name is Jose bar) which is a 20 lb steel bar with a sharp point on one side and a narrow chisel point on the other. You raise it as high as you can and slam it into the ground as hard as you can; it fractures the dirt and you can then use the chisel point to pry rocks and pieces of dirt out of the hole.

Yeah, this is what I bought when I first moved here. It took me two days to dig that one hole, (but hey, I'm retired, lol.)

https://www.amazon.com/gp/product/B000VACVPG/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Lumisol · May 2017

St8kout said:

Lumisol said:

If the air temp in the shade is 120, the surface of the panels in the sun will be closer to 180 to 190. You can fry an egg on them.
You need to secure the panels better than just proping them on a stack of blocks or the first 40 mph gust will launch them into the neighbors yard.
I think your realtor has no idea what he or she is talking about, pools are dug with a backhoe not explosives. Lol

Go back and read my post about how it IS anchored down.
And we're talking Las Vegas ground. Forget using a shovel, you need some kind of pickax here. "If you have dug in your back yard, you’ve encountered this carbon as caliche, a brutally hard, white deposit of calcium carbonate." https://lasvegassun.com/news/2009/mar/03/its-dirty-job/
So it's not hard to believe they've used explosives, as I said, in NEW subdivisions. They certainly would not use them near existing houses. You might remember there was a huge housing boom in Vegas back in the 80's. I'm surrounded by a thousand houses all built during that time. Our subdivision was built in 1985.
Oh, not sure why someone's storage shed was posted, but it's NOT mine, just in case you're wondering:)
The system is powering my A/C just fine during the day. I have not run it at night because I don't want to drain the batteries. The theoretical calculations says I can run it 10 hours just on the battery bank before it drains to 50%. But of course in the real world things are not always so. I have noticed that the Controller meter shows it's pulling some 35-40 watts more from the panels than my A/C is using according to my kill-a-watt meter. So I assume that's about a +10% loss in Inverter/Controller efficiency. (The A/C pulls between 350 and 400 when the compressor is running.) My four 160 watt panels seem to be adequate for my purpose, but I may add more at a later time.

In a new subdivision, houses are built in stages all around before the first landscaping get done so explosives is just a silly idea as they would be breaking windows and doing damage to other structures already in place before the groundbreaking for the pools.

Lumisol · May 2017

Image: https://us.v-cdn.net/6024911/uploads/editor/3b/3uw6mquae8z6.jpg

Garden Shed.

St8kout · May 2017

Hey, I'm just repeating what my Realtor said, and he was born and raised here, and has been in the business some 30 years. If you look at satellite pics of Vegas just about every other house has a pool. The housing boom was so huge that they were selling houses as fast as they could build them, resulting in a lot of cookie-cutter subdivisions. It's not hard to believe they used explosives to loosen up the ground for yet unbuilt houses that were pre-planned to have a pool.

During the housing crisis some 5-6 years ago, whole subdivisions at various stages of construction were being auctioned off because all construction stopped almost overnight from the market collapse. When I was looking for a house here it was a bizarre sight. You would see miles of half completed house frames decaying from the weather. Others were block after block of where they staked out the forms for pouring a concrete slab. Still others were nothing but an outline of dirt roads leading to nowhere.

They do a lot of things differently here. I was surprised to see that ALL home hvacs were on the roof instead of on the ground next to the house. I asked my Realtor about that and he said he hears that a lot from out of town buyers. He was like, "Well, were else would you put it?" Another thing is almost every house has a fireplace, which I thought kind of odd given the mild winters we have. He said the developers found it a big selling feature, even though it's more for show than function, (they are all gas and not rated for burning wood.) So they put them in every house.

bill von novak · May 2017

St8kout said:

They do a lot of things differently here. I was surprised to see that ALL home hvacs were on the roof instead of on the ground next to the house. I asked my Realtor about that and he said he hears that a lot from out of town buyers. He was like, "Well, were else would you put it?"

Were they swamp coolers or conventional (compressor based) systems?

Lumisol · May 2017

St8kout said:

They do a lot of things differently here. I was surprised to see that ALL home hvacs were on the roof instead of on the ground next to the house. I asked my Realtor about that and he said he hears that a lot from out of town buyers. He was like, "Well, were else would you put it?"
~snip

That kind of shows he isn't the sharpest blade in the drawer.

St8kout · May 2017

bill von novak said:

St8kout said:

They do a lot of things differently here. I was surprised to see that ALL home hvacs were on the roof instead of on the ground next to the house. I asked my Realtor about that and he said he hears that a lot from out of town buyers. He was like, "Well, were else would you put it?"

Were they swamp coolers or conventional (compressor based) systems?

These are conventional HVACs. I had mine replaced shortly after buying my house because the home inspector said it was pretty much at the end of it's life and the gas heater portion was badly rusted and could leak carbon monoxide into the ventilation system. Plus the whole house would shake and rumble when the A/C compressor came on, making all my ceiling light fixtures rattle like crazy.

In a way the rooftop HVACs seem easier and faster to replace. A mobile crane showed up and in a matter of minutes the old unit was lowered into the back of a truck and my new Trane was up in the air and maneuvered into place. It's all one unit where all they needed to do was reconnect the gas line and power, hook up a new thermostat, and they were gone within an hour.

I don't think swamp coolers would cut it here in the summer when it hits 120 in the shade, which it has every summer since I've been here.

St8kout · May 2017

Lumisol said:

St8kout said:

They do a lot of things differently here. I was surprised to see that ALL home hvacs were on the roof instead of on the ground next to the house. I asked my Realtor about that and he said he hears that a lot from out of town buyers. He was like, "Well, were else would you put it?"
~snip

That kind of shows he isn't the sharpest blade in the draw.

Or maybe it's all he's used to seeing. Before I moved here from Louisiana I never saw houses with HVACs on the roof. Only office buildings installed them up there.

I've got a lifelong buddy from Louisiana now living in Atlanta, who as a carpenter has built hundreds of houses, plus remodeling, and he's never seen HVACs on the roof either.

So it's just a matter of personal experience.

St8kout · May 2017

Had an interesting morning. You may have seen on the news the released ISIS video threatening Las Vegas (where I live) on Memorial Day weekend. So you can imagine the thoughts I was having when the power went out shortly after I woke up, for no apparent reason, (certainly not the weather with a clear blue sky outside).

At least my modem and router are on UPS backups so I could use my ipad to see that the internet was still up and running. Always a good sign. I was just about to pull out my extension cords to plug my TV and computer into my new solar power system, when the power came back on.

It gave me some justification for building it, in this day and age we live in, especially after the Manchester Islamic Terrorist attack. Btw, his sister said, "He did it for his love of Islam." Yet the public STILL hasn't caught on that Islam has a "covert or die" mandate.

WaterWheel · May 2017

Photowhit said:

littleharbor2 said:

In an off grid system, unless you can make full use of "opportunity loads" throughout the second half of the day you will be losing lots of potential power when your CC is in Absorb or float modes, provided it is designed right. Off grid people know of and take advantage of this potential.

I don't think this helps much for the original poster. Even with the best use of opportunity loads, he's NOT going to run a air conditioner from his small system. The 650 watts of array won't run it by it's self and the battery bank won't run it long. He'll need to up the array and likely the battery bank for the system to do what he wants.

I hope he'll try it out, no reason not to, over a couple days... Perhaps with a clamp meter so he can see which way the energy is running from his battery bank when trying to run the air during the day.

actually with my 1st solar system at 490 watts in panels and 360 amp/hr 12v battery bank I could run the 490 watt (5000 btu) AC for 3+ hours most afternoons/evenings. Not much but it helped.

St8kout · May 2017

I been running my 5000 BTU A/C everyday for a few weeks now, up until around 5:30 pm because then it starts draining the batteries.

I simply went shopping and found THE lowest draw A/C on the market, rated at 410 watts but my kill-a-watt meter shows it never draws that, but only around 350 to 380 when the compressor is running.

In fact, the Controller meter shows it draws about 10% more from the panels than what the A/C is using, which is no doubt because of charger/inverter inefficiency. The meter never shows how much the panels are producing but only how much power it's taking from them. Without a load it shows some 41v @ 0.3 amps or so. Under load the reading was more like 30v @14 amps. It hovers around that but never really stays the same.

https://www.amazon.com/gp/product/B01B4XUUDI/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Every morning the first thing I do is turn on the inverter and A/C. Around 1pm I tilt the panels towards the west. At night I tilt them back towards the east for the next morning. Rinse and repeat.

Lumisol · May 2017

St8kout said:

bill von novak said:

St8kout said:

They do a lot of things differently here. I was surprised to see that ALL home hvacs were on the roof instead of on the ground next to the house. I asked my Realtor about that and he said he hears that a lot from out of town buyers. He was like, "Well, were else would you put it?"

Were they swamp coolers or conventional (compressor based) systems?

These are conventional HVACs. I had mine replaced shortly after buying my house because the home inspector said it was pretty much at the end of it's life and the gas heater portion was badly rusted and could leak carbon monoxide into the ventilation system. Plus the whole house would shake and rumble when the A/C compressor came on, making all my ceiling light fixtures rattle like crazy.
In a way the rooftop HVACs seem easier and faster to replace. A mobile crane showed up and in a matter of minutes the old unit was lowered into the back of a truck and my new Trane was up in the air and maneuvered into place. It's all one unit where all they needed to do was reconnect the gas line and power, hook up a new thermostat, and they were gone within an hour.
I don't think swamp coolers would cut it here in the summer when it hits 120 in the shade, which it has every summer since I've been here.

Swamp coolers will do extremely well in the Vegas area until the monsoon season from around July to Sept. for those months an A/C will be better. The best system uses both together. That's what they are putting in the million dollar and up homes now.

mcgivor · May 2017

@Lumisol said : Swamp coolers will do extremely well in the Vegas area until the monsoon season from around July to Sept. for those months an A/C will be better. The best system uses both together. That's what they are putting in the million dollar and up homes now.

Monsoon in Las Vegas? There is no such thing, very rarely gets over 20% RH,either cool and dry or hot and dry,
https://weatherspark.com/y/2229/Average-Weather-in-North-Las-Vegas-Nevada-United-States

St8kout · June 2017

Lumisol said:

St8kout said:

bill von novak said:

St8kout said:

They do a lot of things differently here. I was surprised to see that ALL home hvacs were on the roof instead of on the ground next to the house. I asked my Realtor about that and he said he hears that a lot from out of town buyers. He was like, "Well, were else would you put it?"

Were they swamp coolers or conventional (compressor based) systems?

These are conventional HVACs. I had mine replaced shortly after buying my house because the home inspector said it was pretty much at the end of it's life and the gas heater portion was badly rusted and could leak carbon monoxide into the ventilation system. Plus the whole house would shake and rumble when the A/C compressor came on, making all my ceiling light fixtures rattle like crazy.
In a way the rooftop HVACs seem easier and faster to replace. A mobile crane showed up and in a matter of minutes the old unit was lowered into the back of a truck and my new Trane was up in the air and maneuvered into place. It's all one unit where all they needed to do was reconnect the gas line and power, hook up a new thermostat, and they were gone within an hour.
I don't think swamp coolers would cut it here in the summer when it hits 120 in the shade, which it has every summer since I've been here.

Swamp coolers will do extremely well in the Vegas area until the monsoon season from around July to Sept. for those months an A/C will be better. The best system uses both together. That's what they are putting in the million dollar and up homes now.

I had looked at it before, but I grew up in the South and had my fill of humidity, be it hot or cold. Mold and mildew are a nonstop problem living there. I so much prefer the dry air here. In Louisiana 85-90 degrees with high humidity is worse than 100 degrees here, as far as my comfort level goes.

Swamp coolers also need the whole house to be open so air can flow through. When my allergies act up that's not an option.

I have to wonder how many of those homeowners with both will, after trying them out, actually ever use theirs, instead of the A/C.

Lumisol · June 2017

They are the primary cooling from March to Mid to late July when the monsoons start. They help to keep skin from getting overly dry and aid in respiration as well. If you use an A/C only, doctors recommend to add a humidifier.

Marc Kurth · June 2017

I removed my post because it was about humidity instead of the topic.

Marc

Any opinions/suggestions on my emergency power setup?

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