Solar update: Adding another kilowatt
 

Sold an extra pickup truck we had, and put the money into another 6 solar panels ( 6 x 175w = 1050 watts )...went just about straight across. Just met the freight truck down at the crossroads.

That will bring our system up to a shade over 3kw ( 18 panels ) and max out what I can put on the two charge controllers.....they will handle 1600 watts each @24v.

First billing period we produced 183kw/hrs in 3 VERY rainy crappy sunless weeks of Dec-Jan.

Next billing period, (4wks) upped that to 279.

Both periods, my trackers were mostly inoperative due to some technical problems with the circuit boards, had to send them back for repairs. Hope to have them back in operation this coming month. With the increased panel amounts, and tracking, I hope to bust 500kw/hrs come spring.

Re: Solar update: Adding another kilowatt
 

Andy, you rock sir.

How many watts do you get during an overcast day? And does the tracker really make a big difference when the sun is occulted?

Re: Solar update: Adding another kilowatt
 

Maybe I better order some of those panels myself and set them on the shelf till I figure it out. Is that the best panel $ for $ ? I am assuming you did all my research for me. Since I have no clue on the matter what suggestions are you willing to make. That is besides get off my ass and figure it out on my own. Dhoo... :banghead:

Re: Solar update: Adding another kilowatt
 

If you're just getting started, you can bang your head a lot more....I did.

First off, you need to decide whether you're gonna go grid tie ONLY, grid tie with battery backup ( for grid down ), or totally off grid. That is going to determine a lot of which stuff you buy, and how much things cost.

For example, the panel I'm using.... Solar World...use to be Shell Oil Co....is a 175w is for a 24v systems that have batteries. You can use them on grid tie only of course ( you can use about ANY panel on grid tie only ), but the voltage they put out ( about 35-36v ) is ideal for the charge controller to step down a little and go in the batteries if it needs too. Cheapest I could find them currently was FRN 745/panel. That works out to 4.26/watt.

Solarworld Panels from "Mr. Solar"



BUT if you were going grid tie ONLY, the Kyocera KD205GX-LP, 205 Watt panel is cheaper at 3.89/watt, but doesn't mesh well with battery systems because each panel puts out 26v....shade too little for 24v charging, and too much for 12v ( those usually run in the 16-17v range )....but since a grid tie system doesn't use batteries, it doesn't matter. Usually what they do on those deals is buy a high voltage inverter, where they will take several hundred DC volts in, and then wire the panels in series so you gang up the voltage times the number of panels....they'll hook 4 to 8 of them together. The advantage of this is you can run smaller wire ( DC is terrible about voltage loss and you have to run huge wires compared to AC ) by upping the voltage.

Grid tie systems are a lot cheaper, since there are no batteries, charge controllers, the inverters are cheaper ( since they aren't dual purpose )....they will run 1/3rd less.

BUT they aren't worth much if the grid goes down.......and thinking like we think, you probably won't want to even look at them.
Northern AZ Wind/Sun

My advice is just jump in. I bought my first panels about two years ago, and then bought pcs here and there along the way....but you'd be AMAZED at the stuff you need and didn't think of until you get to that point in the install. Some of it you 'could' work around in a pinch, but some you can't.

Fire away with questions if I can help.

andy

Re: Solar update: Adding another kilowatt
 

Watts on overcast days vary from nothing to something.....it just really depends on HOW much light the panels get....but crappy, rainy, snowy days, you can figure nothing and be safe.

The tracker doesn't make much difference on overcast days. Where it pays for itself is on sunny days....keeping the panels as close to perpendicular as possible. There, it makes 30% difference in watts. I've checked it by cutting one array out, and letting the other track. Each array I can monitor separate as to production since they are on different charge controllers.....and they tell you exactly what is coming in.

Re: Solar update: Adding another kilowatt
 

i just got 2 inverter last week , they are 1500 watts inverter now i need to find out how many solar panels i well need , i well call the link you posted an find out more , trying to learn what i can so i can used it my farm , how did you hook the power to your home tn , did you go into the breaker box with the power

Re: Solar update: Adding another kilowatt
 

Thanks Andy,

I am not interested in selling anything back to the grid for several reasons but the primary one is the likelihood of the government using compiled data to tax you on your possible consumption somewhere along the way. Then again they will want to tax you for income if you sell any back to the grid.
They have suggested this in wells and septics in this region but as far as I know they have only started putting meters on wells and have not yet started billing for consumption.
We have even heard the drums beat about homeowner taxes being implemented if your home is paid for or will pro rate if you have a modest mortgage left. The way they put it was as such, "you own your home and pay no rent so we are wanting to call that money you are saving by not paying rent and call that income" This is insane I know but they have discussed it in a state where to this date we pay no state income tax.

So I am am interested in getting "unplugged" I have lived without power before and a Solar system would be a great advantage in comparison.

I see a guy that has a wind turbine some miles up the road and that things spins like a airplane. I know he must be getting some good juice from that thing. I see them in a smaller model on the boats but none of my friends have them.

I think there is a green energy show coming to BC soon and I may try to get there. I can start trying to learn this but will no doubt have some questions for you along the way.

Re: Solar update: Adding another kilowatt
 

IF you have wind, by all means, GO THAT WAY.....it's cheaper per watt.....then add some solar for calm days. Best of all worlds. And I understand your desire to go off grid.
Yes, I've heard of the proposed tax on folks with paid off houses, calling it "income"....pure bullshit, for sure. They do that, and I'll go take out the maximum mortgage I can get, and buy gold. Or start myself a "church"....ahahahhaaa....the "Church of What's Happening Now" ( Pope Flip Wilson )


Mick:

Yes, I went into the main breaker panel. BUT BE VERY CAREFUL HOW YOU DO THIS if you go this route. You can't use just any inverter....it MUST be a grid tie type inverter that cuts out from the grid when the grid goes down......otherwise, it will like hooking a generator to your house and back feeding the line. 120v steps UP at the transformer to 2300v ( what they use here on the high side....your may vary ) and WILL KILL A LINEMAN down the line if you do this.....

So unless you are very sure of what you are doing, keep your solar completely separate from your house power panel.

Re: Solar update: Adding another kilowatt
 

i have no elec on my farm , i did not want none on it ... so when we get my new cabin i well be off the grid ,, but i well have a genertor for back up an yes i look up wind for power but in ky it not a good place for it ,, look it up on a wind chart but on my cabin there well be a breaker box out side for the gen an solar.. my dad a elec an my an him is wiring it all for low volt lights ,, i mean low waltage lights , trying to stay with low waltage every thing if i can ,,,, i have a cave with a spring coming out of it on one side on it it maybe a spring house before long

Re: Solar update: Adding another kilowatt
 

That will work.....good way to go.

No, wind probably isn't an option for you......very few decent wind sites in the east, and most of them are on high ridges.

Re: Solar update: Adding another kilowatt
 

what do you know of the tax credits there giving for solar energy , i hear 30 percent on taxes .. have you hear any thing on this yet

Re: Solar update: Adding another kilowatt
 

Yes.......the credit for 2009 is 30% with NO CAP....which is a HECK of a deal.....if you're paying taxes to amount to anything, Uncle Sugar is paying for 1/3 of your system !

That was another reason I added the 6 this year......4500 bucks worth of panels on sale for 3000.

Previous years, it's been 20% with a 2,000 max in one year.

Re: Solar update: Adding another kilowatt
 

thanks tn andy i maybe picking your thoughts on some stuff on solar in the next few days , i should be getting my life insur money any day , then i can get on with my house , well it not a house per say . it a berm home the concert done , waiting on the plumbing now then then floor , it running me 24 k for all the labor an concert , when it done there well be 6 feet of dirt on the place , the whole front of the place well be glass.. the house well be 1350 sf not to bad , not sure if we are going to put wall up in it yet when it done i well post pic ,,, this is why i am tying to do this right the first time

Re: Solar update: Adding another kilowatt
 

I thought we weren't supposed to post porno on here? Cause in my book that picture of solar panels is pure sexiness!!:bear_wub:




You subscribe to HomePower magazine Andy? I've been reading it for a couple years now, picking up some info and trying to retain it. Great technical diagrams accompany every article, which can be really helpful when trying to learn about Solar power.



I'd like to start with a kilowatt or two of grid-tied PV, but have it set-up so I can easily(relatively) switch to a battery bank if/when SHTF. With the rebates being as good as they are I think I'll have to strike while the irons hot here pretty soon.

How much would you say the trackers added to the overall cost of your PV system?

Re: Solar update: Adding another kilowatt
 

Andy,

what are you using inverter wise.....has it performed as advertized?

thx

Re: Solar update: Adding another kilowatt
 

Congratulations on your ongoing success with this project Andy.

Re: Solar update: Adding another kilowatt
 

Just to clear that statement up a bit, its not that DC is worse than AC about voltage drop, its that the more current you run the larger wire you need as larger wire has lower resistance. The formula, I (amps)squared R (resistance) = W (watts) will show that as your amps increase for a given resistance your watts consumed will increase. For example 12 AWG copper wire has a resistance of 1.619 ohms per 1k feet. So if we're running 20 amps in 1k feet of 12 awg our numbers are 20 squared X 1.619 = 647.6 watts. Our 1k feet of wire (500 feet of cord out to our load and 500 feet of neutral conductor back to the power source) is consuming almost 650 watts of electrical power and turning it into heat through the length of the wire. If we're running 4 AWG copper wire it has a resistance of 0.2533 ohms per 1k feet. So, 20 squared X .2533 = 101.32 watts. With larger cable we're consuming fewer watts in the way of heat through the length of the wire causing less of a voltage drop at our load. Now, amps X volts = watts so 50 amps at 24 volts will give us the same power as 10 amps at 120 volts, but with the 120 volt circuit we can use smaller wire regardless of whether is ac or dc.

The main reason AC is used for power distribution is that it can easily and economically be stepped up and down in voltage using transformers whereas with DC you can't use transformers and dropping and raising the voltage is expensive and not as efficient. I hope that explanation makes sense. Its late and I'm heading to bed.

Re: Solar update: Adding another kilowatt
 

FYI, used to build custom solar panels with Kyocera cells, professionally. They're still available. I now use another manufacturers cells.

You're a smart dude TnAndy, you fill in the blank... :puke:

Re: Solar update: Adding another kilowatt
 

"The main reason AC is used for power distribution is that it can easily and economically be stepped up and down in voltage using transformers whereas with DC you can't use transformers and dropping and raising the voltage is expensive and not as efficient. I hope that explanation makes sense. Its late and I'm heading to bed."

We would all be operating off Tesla's direct current (DC) if it hadn't been for Westinghouse and his AC current which for the reason described above did make more sense for long range distribution. Still, Tesla wound up improving the reliability of Westinghouse's AC generators.

As a side note : many of the old power tools will run off 120 volts AC or DC, those tools will last forever if taken care of. I have an old grinder and a drill that I run off my Lincoln A200 DC welder, one of the 3 greatest inventions of all time as the old timers will tell you......the other 2 are the caterpillar and the 9N ford tractor....hey I didn't make it up. The other thing they used to tell me was that the lathe is the mother of all tools.....no denying that one.

Re: Solar update: Adding another kilowatt
 

Pair of Outback GTX2524's. Seem to work fine, but that is based on pretty limited experience so far.

Re: Solar update: Adding another kilowatt
 

I'm reading into that you don't think much of the Kyocera cells ? I have no personal experience with them, but they seem to have a good reputation out there. What brand do you use now ? And what was the problems with the Kyocera ?

Re: Solar update: Adding another kilowatt
 

Are you setting a new stand or adding the new panels on the side of the existing panels?

What is a good source of windmills?

End of questions for this post!

Thanks!

Re: Solar update: Adding another kilowatt
 

Sorry...didn't see your post up there, wasn't ignoring ya.

No, I don't get Homepower, but it sure looks good.

I probably have about 800/ea in my trackers.....control board 140ea, linear actuator 150ea, rest is steel, electrical unistrut the panels actually mount to ( but you'd need something like that anyway even for fixed mount ). I used one controller board for each tracker, but now I'm setting it up with some relays so one board controls both tracker motors.


Armed Peasant:

Adding on to the existing arrays....3 panels on each pole. I think it will handle it fine, and everything ( mount, wiring, combiner box ) is already set up so it's pretty much "plug and play".

Bergey Wind in OK http://www.bergey.com/

Or Northern AZ Wind/Sun http://www.solar-electric.com/


But you don't have a wind site at your house....you know where my internet tower is, and that would be a minimum site.

Re: Solar update: Adding another kilowatt
 

Re: Solar update: Adding another kilowatt
 

Andy

How far could you run wiring from the windmill to battery bank? I may have a chance to put one on the ridge top where they are clear cutting now.

Just a thought, since I do not get a lot of sun either.

Re: Solar update: Adding another kilowatt
 

Payback would vary from State to State, even locally.

For example, I read somewhere Florida has announced they will give a tax credit of 4bucks/watt for solar.

That is HUGE HUGE HUGE ( if true.....I have no source ). Add that to the Fed credit of 30% and you can almost put a system in for nothing. The payback comes every month then.

But most places, you only get the Fed credit, so you have to take 30% off the system cost, figure how much it will produce ( save you ) and do the math to see what your payback period is.....you'll find it's way out there for most installs....like 12-15 years.

I'm sure it does add some value to the house, though I have no idea what.....I never looked at mine in that regards...or payback either, really. I did it primarily so I will have some minimum electrical service if the grid goes down.....insurance before payback.

Re: Solar update: Adding another kilowatt
 

Good primer on wind:

http://howto.altenergystore.com/Buye...-Turbines/a38/

Also, how to size wire:

http://howto.altenergystore.com/Refe...ur-System/a62/


Basically, it's going to depend on the voltage the wind mill.

But say you got a 48v DC model and it was 2,000 watts.

That would put out about 42 amps running in a full wind.

Say you have it on a 60' pole/tower and want to run another 200' from the base to the batteries....260' total....you'd need a 2/0 or 3/0 copper cable to stay within a 3% voltage drop. That's a pair of cables the size of the entry service to your house ! Probably 5-6 bucks/ft ( I haven't checked prices lately, but MUCHO DINERO no matter what ). And that's JUST 200' of run.....how far you looking ? 1/4 mile ?

NOW, your other choice is you put the batteries in a shack right at the base of the tower.....now you get down from the windmill to the shack with a reasonable cable size.....and you mount the inverter there, and transmit 240v AC from there.

Now you could run 900 feet with #6 cable ( 240v, 8.5amp, 2000watt )

You REALLY want to bury 900' of cable in your rocky ground ?

Re: Solar update: Adding another kilowatt
 

As long as your windmill runs at a high voltage, you can park it a long distance from your batteries.
Low voltage requires HUGE copper wires example:
For a 24 volt system I use 6 gauge wire on a 30 foot run from solar panels to charge controllers, and 2/0 ( that is two-ought, double zero) guage wire to connect batteries to inverters. 2/0 copper cable is 5 dollars per foot, and is just (barely) adequate for VERY short runs say 4 to 6 feet from inverter to battery bank.
With a 240 volt system, you can push power from a windmill through 2 gauge ALUMINUM wire, which is comparatively cheep, and you should be able to go 800 feet without too much trouble.
I strongly recommend that you consult with a genuine electrician and spend some quality time at the Library before buying any hardware.

Re: Solar update: Adding another kilowatt
 

Yeah....I've got also got about a 30' run from the panels to the charge controllers, and I used #2 ....that's way oversize, but I had a bunch of it already.....and now adding more panels, I don't have to go back and change it either.

I ran 2/0 welding cable from my batteries to the inverter....and they are also within 4'.


One thing I've found about voltage drop calculators, like HERE is they tend to be pretty conservative.

For example, I have a pair of #8 wires run to the top of the mountain to power the internet radios.....2200'. The voltage calculator says I should get a 27v drop on an 8amp load. Well, I plugged a side grinder in up there one day, and stuck a voltmeter in the other half of the receptacle just to see. It dropped to 104v as I first fired it up, put then came back to about 114 running under no load....then when I grind something, it would drop back to about 112v....which I don't think is low enough to harm the grinder.

Re: Solar update: Adding another kilowatt
 

You can't see it, but I'm green with envy :D

One question though, have you examined the economics vs. sitting on the grid and investment in solar equipment. Obviously if you want the capability to survive off-grid the cost may be something that doesn't bother you so much.

Re: Solar update: Adding another kilowatt
 

Guess I don't quite get your question Shades......

Re: Solar update: Adding another kilowatt
 

If it wouldnt be to much trouble i think it would be good to at least make a recommendation, or the gotcha's in solar panels, for us rookies looking to buy these type products in the near future.

I would love to see a recommendation or ranking of solar panel types and manufactorers and some cost information or a link from someone in the industry

Re: Solar update: Adding another kilowatt
 

i feel the same on that a place you could see all the price an the best for the money

Re: Solar update: Adding another kilowatt
 

Re: Solar update: Adding another kilowatt
 

We also use about the same per month, but this should cancel ALL our bill the way the money works out.

TVA pays 15cent/kwhr for all solar/wind production. ( We buy it at 9 cents )

Then, you get the USE of each hour if your house needs it first ( free ), then it flows to the grid if you don't....worth another 9 cents in cost avoided.

So, we buy 900kwhrs/month at 9cents = 81.00

We generate ( hopefully on a year's average ) 400kw/hrs/month at 21 cents ( I'm averaging the 'free' hours in.....it would depend on what we have running when ) = 84.00

They owe me 3 bucks.

Realistically, I expect it to be about a wash one way or the other.

The BIG plus is if TSHTF, I have enough electricity for some refrigeration, a few lights, and run the washing machine some. Difference between the 20th century and all the previous ones.

Re: Solar update: Adding another kilowatt
 

And don't forget the most important items. PC and Tea or Coffee pot. OF course the woodstove will do for tha later.

Re: Solar update: Adding another kilowatt
 

TN... Andy:


One thing I've found about voltage drop calculators, like HERE is they tend to be pretty conservative.

For example, I have a pair of #8 wires run to the top of the mountain to power the internet radios.....2200'. The voltage calculator says I should get a 27v drop on an 8amp load. Well, I plugged a side grinder in up there one day, and stuck a voltmeter in the other half of the receptacle just to see. It dropped to 104v as I first fired it up, put then came back to about 114 running under no load....then when I grind something, it would drop back to about 112v....which I don't think is low enough to harm the grinder.[/QUOTE]
.... Grinder will survive that, but it will run a bit 'warmer ' under hard use.....

.
. I have a 650 foot run from utility meter base to my house, and have about 1 % voltage sag at maximum load conditions.
I dont know what my loss is on the DC run from solar panels to charge controller, but I do get the ammeter shunt quite warm on a sunny day.
I run a bit over 40 amps into the batteries at 30 volts in winter.
Not exact measure, but the amp meter is pegged hard over.
I have 4 more L16 batteries to add to the system, and the plan for this summer is to add another pair of Kyocera KC130 panels.

Re: Solar update: Adding another kilowatt
 

Thank you for the detailed post, Master Andy...You are saving about $1000 per year so the the system will pay for itself in 15 to 20 years...I am guessing that your home will appreciate by at least 50% of the cost of the system so now your payback is 8 to 13 years..

Independence is your main goal so try to add another 776 watts...:biggrin:

What was the weight of each panel and where they hard to handle:questionm

Re: Solar update: Adding another kilowatt
 

I have Kyocera's over 20 years old putting out over 90% of their rated capacity and they still look darn good for their age.....they'll probably go another 10 years.
I have some 15 year old Photowatt panels that look and put out good power also......all my latest (5year old) are BP panels, very nice, clean jack style mc wires and junction boxs....much better than the old style junction box that you had to wire into, these you buy in pre-determined length sets and you just plug them in .

Re: Solar update: Adding another kilowatt
 

Wow, good for you Andy, lead by example. Thanks for sharing.

Re: Solar update: Adding another kilowatt
 

They weigh 33lbs each.....and no, they aren't hard at all to handle.

I used electrical "unistrut", which is a sort U shaped channel used in the electrical biz for mounting all kinds of things. Comes in 10' lengths, and I welded pcs of it to the rack I made that tilts ( tracks ). Then used the cam nuts you can buy for unistrut, some 3/8" bolts, and a little 3"x2" 1/8" aluminum angle clip ( drilled with a 3/8" hole on one leg ) I had made at a local metal shop between the panels and the unistrut.

Ran some self drilling type sheet metal screws into the leg of the angle sticking up, and into the side frame of the solar panel....two clips on each long side near the corners, two screws in each clip. Should hold from now on...

Pic of the cam nuts and how they insert into unistrut....you can slide them anywhere up and down the channel of the strut....then they "lock" into place when you run a bolt in them connecting to whatever......like my angle clip



http://www.unistrut.com/DB/Group4/SM...er_FLYER_1.jpg


The panels come with a pair of 5-6' lead wires out of a small junction box on the back of them, and you just plug in extension wires to those to get down to a "combiner" box ( which is just a small box with 10a DC breakers ), and from there, a pair of heavy wires on to where the charge controller is mounted ( in my greenhouse ), then on to the battery bank.

Pic of an extension cable.....you get one twice as long as you need with both male/female ends, then cut it in half and run the cut ends into the combiner box/breakers.

http://store.altenergystore.com/mult...Images/mc2.jpg

Re: Solar update: Adding another kilowatt
 

Sorry, I missed this thread...

Their cells have a tendency to develop high series resistance as the tabs on the front peal off the silicon. The cell is made with a solder pad on it, then the cell is tabbed with a solder coated copper ribbon. Their cells tend to have the pads and ribbon peal off the silicon itself (the pads are poorly bonded). Over time, this amounts to high series resistance, leading to an IV curve that loses its sharp knee. This amounts to power loss to heating the tabs instead of delivering it to the load.

If you can find them, the Siemens SP-55's, BP modules made with Saturn cells, anything SunPower, or if you live in a screaming hot environment and have a way to offset the cost of mounting and tracking the UniSolar thin films are all excellent.

You may find success with other stuff, but the above recommendations properly installed will return your investment.

Re: Solar update: Adding another kilowatt
 

Took a break, just seeing this, apologies in advance.

Nub,
I'm not trying to bust your boys here, but I would raise an eyebrow if you were getting 90% of label power from a 20 year old module. Typically, they don't get more than 95% of label power once installed due to a number of perfectly valid and innocent reasons. Getting a 5% loss over 20 years is unheard-of.

[1] Modules are rated for power in a lab under lab conditions. They shoot pulsed Xenon-arc lamps at a module, capturing the data with calibrated sensors telling the system when "1 sun" conditions exist. The problem (for users that is) is that Xenon-arc lamps aren't the same output as the Sun in spectral output (biased towards UV, actually got a 'sunburn' on my right hand from using the damn sun tower testing oversized modules). This leads to an error between performance in the tester and performance in Sunlight.

[2] In addition, because the test is so short the module never gets HOT like it does in the Sun. HOT solar panels suck compared to cool solar panels. If you have solar, wait for your panels to get good Sun for an hour or more, measure the POWER (not just current or voltage). Turn your hose on full bore on the solar panel array (safety caution). Watch the power go through the roof as you cool the module. It might take 5 minutes to get through your glass faced modules, but it'll go ballistic if your water is cold and the ambient temperature is high (no wind either, wind alone makes a big difference when ambient is high). This fact alone will account for most of the mis-match between the label and the real world. Under HOT ambient conditions and killer Sun you can tap 90+C for the surface of the module. (If you live in Alaska or someplace cold this wouldn't apply to you as much. :)

[3] How are you measuring this power? Are you looking at the true power delivered or measuring the IV curve? The IV curve tracer is the "Solar MRI machine", and I don't know anyone that has one for less than $20k other than mine. And I haven't sold you one, yet! ;)

[4] Unless you live someplace really high, or have exceptionally clear sky, you almost never get the full 1000 Watts/sq meter insolation (light intensity) that the modules are rated with. The manufacturer calibrates to 1KW/sqm, but it's really tough to get that in real life. Haze, fog (even the stuff you can't see), high thin cirrus clouds, dirty glass face, UV yellowing of the EVA, angle to the Sun (time of day, time of year), all this stuff conspires against you. Summer on a clear, windy day, with short cables, new clean modules MIGHT get rated power, until they get hot which will be <30 minutes.

[5] If you're measuring power at the module, you'll skip the line loss. Most people look at the inverter power to see how things are performing. Since the inverter is far away from the modules, there is an I^2R loss hitting the power reading.

[6] Polycrystalline cells have a tendency to degrade over time due to the nature of their structure. The little individual crystals that compose a cell start to break away from each other (micro-fractures) leading to progressively higher resistance. The cold-hot-cold thermal cycles the module sees every day mechanically stress the crystalline interface. The single crystal stuff is immune to this failure mechanism.

[7] The manufactures ALL sandbag, every last friggin one of 'em. There's a tolerance on the power rating, and you can bet your wife's TIVO that you're getting the LOW end of the tolerance. So a 50W module is rated 50W +/- 5W (ie 10%). Means it's gonna test out on the manufacturing line at 45.0W.

[8] The annealing process is where the stress in the cell and lead (solder) is relieved. Annealing has positive and negative effects, and only time and thermal cycles will get the process done. There's a reason that modules are rated as soon as possible though...

Seriously, I glad your modules are performing for you. It may be that you have the ideal solar installation and the modules aren't thermal cycling too badly. It's best for the industry if there isn't a rash of dead modules popping up inside 20 years as that starts to wipe out the ROI. My experience with their stuff is about 10 years ago, and it hasn't changed from what I've heard recently. (Besides, polycrystalline cells aren't all that good to begin with. Do it right, buy single crystalline cells or UniSolar*)...

Oh, and if you ever get the bright idea to back your solar modules with aluminum to help get the heat out, try it on a sacraficial module and let it run for a year before you modify the rest. Obscure words of wisdom! :wink:

That got a little long, but might help everyone out some, so it was worth it...
Orion :wavey:

*If you buy UniSolar, you better know why you're buying it. It's good stuff, but its only competitive in the right application (apple vs. orange kinda thing).

Re: Solar update: Adding another kilowatt
 

Orion:

I find exactly what you say with mine. Best I can tell, the most I'm getting out of a 175 watt panel is about 160 watts, that being based
on what the charge controller is telling me for the entire array.

One thing about power output is going to be HOW the panel is mounted. If the panels are a fixed, roof type mount, the power is going to follow a bell shaped power curve as the sun comes up in the morning ( doing about 20-30% in early sun hours ), peaking at maximum power at noon, then falling off thru the afternoon again.

Also, there are only two days in the entire year that fixed mount panels will peak due to the tilt of the earth in relationship to the sun, just like the morning-evening bell curve, with all the other days being on either side of that.

I have the two arrays mounted on homebuilt single axis tracking mounts, and so the "up-down" angle is fixed at the mid point for the summer-winter angle here ( 37 degrees ). I was hoping to pick up quite a bit of extra power from the horizontal tracking, and I know it does because I've played around with moving them during the day....for example, if I move them to the "noon" position, which is where most roof mounted panels would be fixed at, when the sun first comes up in the morning, they are only doing about 20-30% of the theoretical array total....but I can crank them full east, and it bounces right up to 85-90%....

It's been fun to play with them and watch them track during the day, but honestly, the numbers don't work out for tracking mounts IMHO. Even with my home built trackers, in which I have about 1000 bucks in each, I think based on the numbers, I'd have been better off to simply roof mount them and spend the tracker money on extra panels.

Re: Solar update: Adding another kilowatt
 

It's funny you should bring this up, as I was having this exact discussion with a friend last night.

Sadly, the next case of beer will be on me; I was arguing in favor of trackers. I have to say I'm a bit surprised by your observations.

Re: Solar update: Adding another kilowatt
 

Well, Bass, you can probably call it a draw on the beer....because you'd have to consider if you are talking commercial trackers or home built.

Say you have a 100watt panel fixed on a roof mount....the power builds on it from sunup at zero to the "most you're gonna get" at noon and going back to zero at sundown....because solar cells produce their peak power when the sun is 90 degrees to the face of the cell, and power falls off as that angle increases....which is does with a fixed mount. ( I know you already know this...that is for the folks that don't know it )

You also have the "earth tilt" problem. If you fix mount a panel to the roof, there are exactly TWO days of the whole year it will produce maximum power at noon....probably spring and fall equinox if you picked the right angle between summer and winter solstice for your mount for your area ( I did this on my "up-down" mounting of my trackers....they only track on one axis....east-west ). It's not nearly as big a problem on this axis as it is for the east-west because the tilt of the earth doesn't vary THAT much from summer max to winter min and if you mount right, you're hitting the middle of the road with your mount. My understanding is adding that axis to a tracker adds about 6-8% increase.....so I didn't do it.

So say, with that bell shaped curve of power, you hit a 50% average for the day on a fixed mount.........and say the "day" is 6 hours of sun today. The BEST the panel is probably going to do, dead on at noon, is say, 90%-95% of rated power, or 90-95 watts in this case....but for the WHOLE day, it's gonna be 50% or 50 watts. 6hrs x 50watts = 300 watt hours for THAT day.

A tracker is probably gonna hit 75-80% of that same power rating, or .75 x 90 = 68watts. 6hrs x 68 watts = about 400watt/hrs for that same day.....100 extra watt/hours.

So what would it take to get that extra 100 watt/hrs from a fixed mount for that same day ? 100/6 = 17watt.....and at 50% efficient, just double that......34 watts of extra panels would do the same thing.

Now for the real world:

I have two arrays of 1050 watts and each tracker cost me about 1000 bucks....and a commercially built one would have been 2-3 times that, easy.....but stay with 1000 bucks.....

1050 rated watt output, but say it's really only doing 90% of that....or 945 watts ( ballpark ).....I would need to add about 30% more panel area, or 315 watts...that works out to right at two more panels ( plus wire,mounts, etc ), which would be about 2,000. So, in MY case, with home built trackers, I'm coming ahead slightly....I think....not counting any of my labor to build, erect and maintain them, but if you bought commercial trackers and had ANY labor in putting them up, etc, you would go in the hole.

A Zomeworks passive tracker ( no motors.....uses a freon tube ) that would hold 6 of my panels ( and be maxed out at that ) costs about 2k.....not shipped, not installed.

The smallest Wattsun active tracker (single axis, w/motor ) that would hold 10-12 of my panels would run 3100 bucks, plus shipping and installation...

So you can see the only way I'm coming out is by home building them, and counting my labor input as zero.

Re: Solar update: Adding another kilowatt
 

I could have saved you that case of beer, this is something I've already said more than once, guess no one pays much attention cuz I'm not the most coherent to read, 25 yrs. producing ALL my own power via photovoltaics should account for something,,,,,still, Andy has learned a lot, he lost a little money and time but gained knowledge through experience. To be honest I hate to see my panels just sitting there not tracking, seems like an awful waste and I've teetered back and forth for years over this issue,but everyone/anyone in the industry will tell you to buy more panels instead of trackers. Where spacial limitations are a factor tracking may still be the way to go, besides as fast as this industry is changing far be it from me to act the know-it-all.

Panels are one thing but batteries are the bigger pain in the arse when your totally off grid like me......every 10 years or so rolls around pretty fast and lead acid (forklift batteries) are most likely what I'll use next time around Even after over a century of use, they still offer the best price to power ratio. So as I said above "as fast as the industry is changing" but is it ?......after all these years I'm still using lead acid batteries fer Criss sakes ! .

There's always knowledge to be gained from these threads......for me some new suppliers and ideas in general. Andy's root cellar post spurred me on to building one myself, damn near done , will be pouring the roof this or next week and will provide a light and power via solar panels, might even put a sunfrost fridge in it that is not in use, since I'll have power there anyway...I dunno.

Re: Solar update: Adding another kilowatt
 

Your examples are based on a perfect world scenario.....not trying to be negative, jus sayin
In the case of Zomeworks foggy or cloudy days can and do throw the trackers out of wack......loss of power

Years ago I thought wattsun was going to be the hot set up but hasn't faired much better ......mechanical problems.

It all boils down to dollars per watt......maybe if someone could figure out a cheap freon set up that would rock the panels in daisey chain fashion (I've toyed with this idea)

Re: Solar update: Adding another kilowatt
 

Great post, I'm with you on the single crystalline panels.

I laughed at the "I might raise an eyebrow" part of your post, OK so maybe I'm off a bit on my % assessment :biggrin: but they are performing even better than I thought they would at this stage.....I'm at 1500' elev. and clean environment, spanish moss grows in the trees some say that's indicative of pristine conditions, I dunno. What's surprising is this place commonly sees 100deg. days throughout summer (central coast Ca.) not as bad as Arizona but still you would expect to see these temperatures take more of a toll on the panels.

I have some first generation thin film amorphorus panels that I bought from Gary Star up in Rohnert Park Ca. about 19 years ago that are absolute crap......bubbling and de-laminating, this started 10 years ago, I would be very leery of thin film, can't beat a good single crystalline panel.

Re: Solar update: Adding another kilowatt
 

Great info from all of you guys!! The timing is perfect, as I think my buddy will be adding solar this year.

Re: Solar update: Adding another kilowatt
 

How long in the solar industry does an idea usually take getting to market? I'm asking this as I read a while back that a university had developed a coating for PV which reduced the loss of production as the sun angle to the cell increased. Looking at possibly adding this to a cabin I'm building and wondering if this will appear soon to help aliviate the problem of not having moving PV cells.
:coolbeer:

Re: Solar update: Adding another kilowatt
 

Good ideas get incorporated pretty fast, just like any market. Solar is afflicted with a general lack of popular education about how it works. As a result, any wacko with a 'get rich scheme' can target the solar market and probably hook a few suckers into a pump and dump.

As for all the university stuff, some of it is really good (University of New South Wales for example). Most of it is vapor-ware. The biggest hurdle is to survive 10,000 thermal cycles, 60,000 hours of UV radiation, and constant attack from water. Not too many professors get that... ;)

Orion

Re: Solar update: Adding another kilowatt
 

Wow, someone that gets it. The $/whr is arguably more important, but close enough!

The best tracker I saw was on a college solar car team. They built a big 2x4 pyramid, stuck the array on top, and told a freshman to point it at the Sun. Easy to build, cheap, and maximizes the talents of a mechanical or electrical engineering freshman! (CivE's weren't allowed to touch the solar array)

Remember, the tracking accuracy doesn't have to be all that good. You're dealing with the peak of a cosine function, so a few degrees error doesn't really add up to much. That said, make your tracker with three settings and have it flip between them on a timer. One points eastward, one at the mid-day optimum and one westward. Cheaper cause it's dumb (time driven, not Sun sensing), isn't continuous (doesn't require fine, continuous, motor control), and gets most of the power you'd get with an ideal tracker...

Also, bias towards the morning Sun since it will get you more power for a given watt of insolation due to the air and panel being cooler than afternoon Sun.

Zomeworks trackers are pretty slick, but that damn hydraulic damper underneath always seems to need repair or tinkering.

O