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RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495
Posted: 10:43am 27 Jun 2010
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I have 5 arrays of 6 series 100W modules, and one of 6 series 75W modules for a theoretical 3450 watts.
Here's a photo taken a couple of weeks ago (click for larger image):
Thats the current from each array (operating at a little under 100V DC)
Here's the charge controller taken a moment later (also click for larger image):
That was close to solar-noon, about 15 deg C outside at the time. Given the length of cable runs etc (each run is from 17 to 25 metres), it's probably not bad.
rgormley Senior Member Joined: 22/02/2006 Location: AustraliaPosts: 245
Posted: 10:43am 27 Jun 2010
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ok just read that and my brain just started leaking out of my left ear...
petanque don Senior Member Joined: 02/08/2006 Location: AustraliaPosts: 212
Posted: 01:40pm 27 Jun 2010
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I haven’t read the whole post but there seems to be confusion on the dimensional analysis
Isn’t a
watt a joule /second?
An amp a coulomb per second?
Electricity is an abstract thing but the models used to explain it are consistent and have stood the test of time.
Confused and uncertain?
There is nothing wrong with this until you decide the rest of the world must be wrong.
What are the chances of thousands of people being wrong and you being right?
This would depend on all sorts of things.
However Occam’s razor comes to mind
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 05:04pm 27 Jun 2010
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[Quote=RossW]More like calling thunder lightning. One is an effect of the other, but they're totally different.
You mean to tell me thunder's not caused by clouds bumping into each other?
Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333
Posted: 05:27pm 27 Jun 2010
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Thunder is an angry god and lightning is him playing with electronics and the magic smoke getting out.
Or to put another way.
Lightning is Mac doing electrical work, and thunder is Oz bashing his head against the wall tring to teach Mac.
Pete.Sometimes it just works
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 11:37pm 27 Jun 2010
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Hi Ross
Thats a good setup and it really shows the benefit of a MPPT by the results you are getting from your logger.
I like the separate meters to compare each array as it would pick up on and faults at a glance, Last week I ordered 10 meters to do a simular setup, I am using 24 volt nominal system so as not to have any series-ed panels as I found that panels have a slight difference and when in series they tend to deliver the amps of the lowest yield panel, the other reason is dealing with high voltage DC is a bit of a worry.
Are they all on trackers or fixed position as it is a very good yield result.
All the best
Bob Foolin Around
RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495
Posted: 12:07am 28 Jun 2010
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Yeah, I agonised over shelling out for the MPPT charge controller, but I'm glad I did now.
Yep. I had an actuator go sticky on me - the meters immediately told the story.
If anything gets covered in bird-crap, dirt or whatever, it's easy to see without having to actually go for a hike to see them.
I settled for 6 series "nominal" 12V modules per array. Because I have moderately long runs of cable, I wanted to reduce the losses without spending a fortune on cable. I also wanted the advantages of monitoring and logging each array etc. Picking 6 series arrays keeps the voltages below "scary" DC at around 120V open, while reducing the current and cable requirements.
A mixture.
Originally I had banks of 4 modules that fed directly to my battery bank. I rarely had more power than I used, so charge controller wasn't needed. Then I added more modules and had to put in a controller, so decided to re-jig things and up the voltage.
The original 75W panels are on a commercial tracker (but only 4 of them for the 48V system), the balance are on the ground (they were a second array of 4, I'm only using 2 of them for now). I'll rebuild or replace the commercial frame to take 6.
There are 12 modules (2 arrays) on a "fixed, linear" array - but it's not really fixed, it has seasonal adjustment (elevation only).
The remaining 18 modules are split across 3 tracking arrays of 6 modules each.
(Click on images for larger versions)
This was them before their positions were tweeked:
The arrays each come in via their own 2-pole DC-rated breakers. Not really for panel protection, mostly for MY protection if/when I am working on them, as isolators:
The inside setup. 3 banks of 24x2V/500AH AGM is (faceplate) 1500AH @ 48V, the 5KW (10KW peak) inverter, charge controller, solar monitoring and wind control+dumpload:
Battery/cable protection is via 200A HRC (also DC rated) fuses:
You can see inside the meter box here, a copper bar with 6 TO-220 style 16 amp, 150V
schottky diodes. I know they're not strictly required, but I'm much happier knowing that if one array is shaded, it's not going to be horribly reverse-biased by power from all the other arrays. The bar also forms the common + rail. (Yes, slightly unusual, I've chosen to use low-side metering. This is because I plan to build a multi-channel logger, and this way I can use the meters themselves as the current sense shunts for a simpler logger and no additional losses with extra shunts)
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 01:37am 28 Jun 2010
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Hi Ross
Thats a really good setup, I like the idea of separate panel array concept as a way to work on them and by isolating a section without shutting the whole lot down.
You have certainly put a lot of work and thought into the setup top stuff. I like the low end metering also as there isnt any high voltage across the metering.
All the best
BobFoolin Around
dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574
Posted: 06:34am 28 Jun 2010
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Hi Ross
I have seen this before few years ago however l have notice now that is all new batteries has been replace and so what happened to others? And still got Mazda generator running ?
Regard Dwyer
RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495
Posted: 06:51am 28 Jun 2010
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The yellow bank on the floor might be the old ones you remember? There was also 8 Trojan T106 flooded cells, which have been redeployed elsewhere (mixing AGM/VRLA and FLA technologies was just too cumbersome).
With the extra PV I added, I really needed more storage, otherwise it wasn't really going to make much change to my propane demand. The old cells have had a pretty hard life - they got charged and discharged at least twice a day, some days more. They were old when I got them, and I believe them to be close to 3000 cycles - and to well beyond the 10-20% we'd like to manage. As a result, they were really only managing to deliver about 150 amphours before their volts were "dangerously low" (45.3V)
So, I picked up 2 more banks of used but still in "pretty good" condition. My thought is that 1000 AH capacity would let me easily go from mid-afternoon on one winters day (output from PV is pretty much gone by 16:00) and last until the next morning. If there is no fog, I'd manage, but the last week we've had thick fog that hasn't lifted until at least 1pm.
Yes, the home-brew genset using the modified engine from a ford laser (mazda motor) is still running fine.
dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574
Posted: 07:05am 28 Jun 2010
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Hi Ross
That is good to hear from you and I think it long time since we have discuss about engine speed controller and now never brought one as was to expensive to buy so l made speed governor by radiator fan to control engine speed just like small portable generator have air control governor to keep rpm control and still using Toyota engine to run 3 ph generator for my lathe and other equipment Regard Dwyer
Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566
Posted: 05:44pm 28 Jun 2010
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MacGyver ;
Thanks for the PM , Interesting Layout you have described. As you know Seattle sunshine is about 60 days in a Good year. I will not be working on this Solar project for personal use.
It was an Idea that could serve an outback Home or a Community if enough capital is available to pull it off. At 1000 watts per Sq. Meter, a Collector of 20 ft. square would receive 9 kilowatts Solar. At only 20% efficient the gas turbine-Gen would output 1.8 kilowatt per Hr, about 14.4 Kilowatt per 8 hour Sun day.
Time has proven that I am blind to the Obvious, some of the above may be True?
Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566
Posted: 06:00pm 28 Jun 2010
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VK4AYQ;
Thanks for the sharing of a very interesting setup in the use of refrigerant for generating power, perhaps you could share, Lessons learned. Problems encountered, or what you would make different next time?
I,ll be on walkabout for a month. and may not have Opportunity to answer.I appreciate the Knowledge You give to this Forum
Regards; Roe Time has proven that I am blind to the Obvious, some of the above may be True?
Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566
Posted: 06:04pm 28 Jun 2010
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Grub;
And all the Folks on a crash course to master Electricity
Time has proven that I am blind to the Obvious, some of the above may be True?
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 04:34am 29 Jun 2010
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Hi Greenbelt
Looks like a Chinese AA battery, Energy + Short term power = not much work done.
BobFoolin Around
Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566
Posted: 05:27am 29 Jun 2010
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Hey Bob;
That's a ten four on the Double "A"Time has proven that I am blind to the Obvious, some of the above may be True?
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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