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Solar panels


JustAndy's Avatar
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06-04-10, 09:43 AM   #41  
Sure....this is the backside, which probably shows the most detail.



Construction details:

"H" sorta frame ( black ) of 1.5" sq tubing, welded to a 2" steel shaft, set in two pillow block bearings. Bearings bolted to a pc of 2x8 channel, channel welded to 6" sch 40 steel pipe at 37 degrees ( latitude here ), pipe set in 4x4x4' block of concrete. "H" frame pivots east/west on the shaft ( shaft sticks out just past ends of channel ), powered by a 30vdc 36" stroke linear actuator ( like they used on the old C band sat dishes )....one end bolted to "H" frame, other end on a bolt welded to pipe (below level of photo) Power to actuators controlled by a board/sensor made by Analoguy.com ( one board does both dishes )

Then welded electrical Unistrut to the "H" frame to mount panels.....using an "L" clip made of 1/8" aluminum ( local metal shop made for me ). 3/8" unistrut cam bolts on one side of the clip, self tapping sheet metal screws on the other leg into the panel sided.

Wiring from panels to a Midnite combiner box ( 6 circuit breakers ) on the left side of the pole ( grey box ), then a pair of #2 copper on down conduit to the "electrical room" in one end of a greenhouse below....comes into a fused DC disconnect.

Panels installed at two different times....first time 6 on each tracker, then I bought 6 more ( the ones you can see light thru the backing ), and put 2 on one, and 4 on the other. Did that because the panels are wiring in pairs of two.

Poles before panels mounted or greenhouse built:



After first 12 mounted, and greehouse built:



DC disconnect from panels, and two Outback charge controllers.....one for each array.


AC side of inverters ( left ), two inverters mounter horizontally, ( center ) and 175a DC breaker from battery bank ( white box, far end )

 
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JustAndy's Avatar
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06-04-10, 10:00 AM   #42  
Inside greenhouse, you can see the electrical room ( which is now walled off w/door ) on the far end. Battery box is below




Used lead acid deep cycle L-16's at first, (800amp/hr ) then changed to a bank of Absolyte LNB cells ( Absorbed glass mat type batteries ) (1200amp/hr)




 
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06-16-10, 03:19 PM   #43  
Thank you for the pictures. I'm not currently installing a solar system but your posts have gotten me thinking in that direction.

 
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06-20-10, 07:29 AM   #44  
danger

Another consideration is the danger. We're protected from the grid but there's no obvious way to shut down 600 volts worth of panels. Something will go haywire. Murphy's law.

 
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06-20-10, 02:11 PM   #45  
"no obvious way" ??" "600volts"?

My system is 24v, and the panels themselves are 35 volts......and there are disconnecting breakers right under the panels in the combiner box, another DC disconnect at the incoming point to the power room 25' away, another right after the charge controller, 2' from the previous one, and another between the battery and the inverters.....that's FOUR different points it can be "shut down" on the DC side....then the AC side has two sets of breakers 6" from the inverter....one shuts power off to the grid, the other shuts power off to the house transfer switch ( also another disconnecting means ), and then at the buy back meter, the power company requires another AC disconnect with a red warning sticker on it so they don't even have to enter my power room to shut it off from their system.....I guaran-dadgum-tee-ya there are WAY more means to cut off a properly installed solar power system than any typical AC house system.

And as for 'protection' on a grid system....unless you have installed supplemental surge/lighting suppressors, you're WIDE open to surges. We're at the end of the power line in out valley.....and the power line acts as one, big lightning rod. I used to could hear electricity actually crackle in the receptacles, then hear a clap of thunder a few seconds later from a storm miles away. Cured that with a Syscom whole house surge supressor, and I have Delta supressors all over my PV system to protect it and us.

 
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06-20-10, 04:50 PM   #46  
I'm betting mcircus likes trolling.

Mighty nice of you to reply to him in a proper civilized manner.

 
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06-20-10, 05:23 PM   #47  
I dunno about trolling.....I assumed he was refering to a story out of California ( I think it was ) that was out there few months back where roof mounted panels started a fire, or maybe the house caught fire, and then the PV system became involved....I can't remember the exact details, makes no difference....anyway, the story as I recall, said the fire department simply stood around while the house burned, or the PV system arced all over the place while they waited on an electrician to come disconnect the PV so they could safely fight the fire.

In grid tie ONLY systems ( which mine is not....grid tie w/battery backup ), they generally DO run high voltages ( 400-500vDC is not uncommon ) by stringing the panels in series. One panel is 35v, add another, you have 70, add another you have 105, and so on. The inverters for grid tie only are often set up to handle that kind of input, and there is a real advantage to going that route....the amperage stays low.....in the 5-8amp range since you are series stringing, which allows you to use fairly small gauge wire and have very little voltage loss ( a much bigger consideration in lower voltages set ups )...my charge controllers, the first real device downline of the panels, have a 150vDC max input, and when you allow for cold weather and a safety derating, about 120 or so is the max you really should go.... so my type system is far more limited about voltages.

BUT even that one in CA sound more like a lack of training on the FDept's part....SURELY they carry a pair of heavy, insulated wire cutters on the truck....couple snips of the panel leads and it's over for output....and that assumes there was no disconnecting means ( which I find hard to buy given California propensity for codes ) right AT the panels.....a simple 10 buck knife type switch in a weathertite box, if nothing else.

At the most, that was an isolated incident.

 
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06-20-10, 06:18 PM   #48  
I'm seriously considering a PV system and appreciate the debate. What's trolling?


Last edited by mcircus; 06-20-10 at 06:45 PM. Reason: Further research confirmed original fears
 
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06-21-10, 07:44 AM   #49  
This brings up an interesting point. There really is no on/off switch for a solar panel. You can have a disconnect but the panels are still producing power. What happens to a panel in the sun when it is not hooked to a load?

 
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06-21-10, 11:00 AM   #50  
Posted By: mcircus Don't equate low voltage with safety. My welder output is often 24 volts rms. dc. Though arcing is unlikely once struck the conducting plasma melts steel. Short of draping something over the panels, they're pumping. A disconnect isn't a shut down. I'dd isolate any array away from buildings.
Yes, my welder puts out voltage somewhere in that range as well....AT SEVERAL HUNDRED AMPS.

Lower voltage IS more safe than higher voltage. Voltage is potential, not power. The higher the voltage, the more potential is has to move, including move thru insulation on wire ( that's WHY there is a 600v limit on many types of wire ), or even bridge a gap.....like a spark plug.

The ignition coil on your lawn mower has several thousand volts so the plug will "spark"....but also almost no amperage....and without the combination of the two, there is little power. It can, and will, sting the crap out of you if you grab it, but mostly likely won't kill you, as it's low power.

Panels don't "pump" any more than the battery in your car does....both have POTENTIAL...but without a load ( which would include a dead short ) connected, there IS no electrical flow.

The battery in your car has the POWER to weld metal ( albeit for only a short time ).....and the gasoline in the tank has the explosive potential of a case of dynamite.....and yet people foolishly park them in their garages every day....ahahahaaaaaa....and if you knew how much power was contained in the battery of a laptop computer, you'd NEVER actually put it on your laptop, lest you lose your lap....ahahahahaa....yet, I see it all the time....amazing, huh ?

You're making a mountain out of a mole hill......put your panels anywhere you want ( I'd suggest a sunny location, but it's your nickel )....mine are on a pole in the yard, but not for the reasons you're worried about....but DO learn more about electricity if you plan to get some.

 
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06-21-10, 03:20 PM   #51  
Everything you said is true. Everything I said is true. Let's debate more.

 
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06-21-10, 03:40 PM   #52  
I've only used a single 5w single panel so I don't really know what I was expecting from a PV array with no load applied. I was mainly curious if an array would damage it'self is operating without a load. I did not know if it an array would reach its potential and then just sit there or if it would continue to build a charge until something arced. It sounds like it is self limiting. Once it "charges" itself up to voltage (potential) the process stops.

 
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06-21-10, 04:43 PM   #53  
you guys are complex

This discussion seems to be way above the average person.

Are you all attempting a DIY? I thought about it & then decided not to try it. Call it fear of the unknown.

Even though I bought my system I am very interested in what you are writing but I am lost in the Tech Talk. I'll just keep reading & see if I can learn something.

 
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06-21-10, 06:46 PM   #54  
OK....if this is a flame war, you guys are leading sheltered lives...ahahahahaaa....

I generally don't flame.....if someone keeps on and on to the point I think it's trolling, I simply don't bother answering them anymore.

 
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06-22-10, 04:14 AM   #55  
[QUOTE=JustAndy;
but DO learn more about electricity if you plan to get some.[/QUOTE]

Is there a photovoltaic bible?

 
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06-22-10, 07:31 AM   #56  
Get a subscription to Home Power magazine.

 
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06-22-10, 07:53 AM   #57  
thanks guys

I can now understand the postings & find them quite
entertaining.

 
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06-23-10, 04:01 AM   #58  
Prefer something like the equivalent of "Machinery's Handbook" for Machinists. I have the last 23 years of Home Power.

 
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06-23-10, 04:32 AM   #59  
Thank your for mentioning Home Power Magazine. I've only spent a little time reading their site but have found "the basics" sections very helpful to learn some of the terminology. I might have to break down and get a subscription.

A bit off topic but I love the article about mini-hydro. I've got the elevation. If only my creeks flowed more reliably.

 
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06-23-10, 08:56 AM   #60  
Micro hydro is a great way to go...problem is, as you've discovered, you either have to have a decent flow with plenty of head, or LOTS of flow if low head.

Once you get into a stream that actually has enough of either to generate, you also get into all kinds of environmental permitting problems as well. Basically, the unregulated water flows are the ones that also dry up in summer, fall.

 
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06-23-10, 09:54 AM   #61  
Posted By: mcircus I have the last 23 years of Home Power.
On a CD and you haven't actually read much of them, right ?

 
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06-23-10, 09:59 AM   #62  
Posted By: JustAndy OK....if this is a flame war, you guys are leading sheltered lives...ahahahahaaa....

I generally don't flame.....if someone keeps on and on to the point I think it's trolling, I simply don't bother answering them anymore.

The above was in response to a post made by a moderator, who has since removed the post

Note of the Moderator of this forum: I am not the person who did the comment, but I am the person who removed the comment. I don't find you comment inadequate


Last edited by pmgca; 06-23-10 at 05:27 PM. Reason: add moderator's note / edit comment
 
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06-23-10, 03:58 PM   #63  
This is not an indorsement or DIY

Good news. A new panels with an embedded power optimizer, monitor and inverter was introduced last month. Say we use 20 small complete systems. If the worst happens we're talking 350 watts not 7000.

Excerpts from Solar Edge Tech.

To eliminate risk of electrocution at times of installation, maintenance and firefighting, PowerBoxes shut down each PV module's DC voltage as long as the inverter is deactivated or AC power is disconnected. The PowerBoxes will also shut down the modules immediately when electric arcs or high temperatures are detected to prevent fire.
They can also be monitored via over the power lines

 
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06-23-10, 06:38 PM   #64  
You could just throw a tarp over the panels to shut them down if there were no other safe means.

 
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06-24-10, 07:41 AM   #65  
inverter

mcircus,

When I had my solar system installed I asked about safety with the power coming from the solar panels and getting to the grid on the other side of the house.

The electrician explained why they installed one inverter on each panel rather than one inverter for all panels. Sounds just like what you just posted. It also makes the entire system operate better with individual inverters when one panel fails or shade covers a panel or two.

I emailed the solar company to find out what they suggest in the event of some mishap (besides turning off the breakers).
I believe the inverters have some built in mechanism to shut down each panel.

So far no answer so I will email them again today.

 
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06-24-10, 10:05 AM   #66  
Posted By: TTASHA When I had my solar system installed I asked about safety with the power coming from the solar panels and getting to the grid on the other side of the house.

The electrician explained why they installed one inverter on each panel rather than one inverter for all panels. Sounds just like what you just posted. It also makes the entire system operate better with individual inverters when one panel fails or shade covers a panel or two.

I emailed the solar company to find out what they suggest in the event of some mishap (besides turning off the breakers).
I believe the inverters have some built in mechanism to shut down each panel.
.

TTASHA
Sound's safer from us fools too. A bunch of small complete PV sets. Soon installing PVs will be easier than plugging in a TV. At least a TV on the roof. mcircus

 
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06-24-10, 11:42 AM   #67  
This post may be considered slightly off topic as my installation is on our sailing catamaran, not a residential home, but it was a totally DIY project. We have 4 Kyocera 130 watt panels in two "banks" of two panels each, connected in series to produce about 30 VDC output. The two banks are connected in parallel at the input to our Outback MX 60 MPPT controller, which produces appropriate DC voltage to charge our lead-acid house batteries. On a sunny day, we can see up to 25 amps output at 12-13VDC, enough to meet the routine demand on our house bank and even to run the watermaker at anchor.


Last edited by pmgca; 06-24-10 at 11:51 AM. Reason: contact comment removed
 
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07-20-10, 12:41 PM   #68  
SOlar

Well i am from bangladesh and it does have poor performance during rainy season so weather condiitons are a factor.

 
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07-20-10, 02:39 PM   #69  
little sun means no reason for solar

Nailcutter,

You are absolutely correct. If you don't have AN EXCESSIVE amount of sun - solar is wrong for you.

When it rains or is cloudy in Florida the solar system produces very, very little power but on sunny (most days) it is great.

Geo-thermal is something I know little about but I think it is good here and could be good in your country. I haven't tried that yet.

Everyone wants to save money & many also want to save the environment. I want both.

 
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