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Forum Index : Solar : Serious Solar
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
I went to a friend's house today in a neighboring town, Vista, California. Turns out my friend (much older than myself) is in God's waiting room; very ill, etc. I snapped a few shots of his solar application. This thing is as big as a backyard swimming pool! It sits at the south side of his house (mansion!) at a tilt of our latitude (38.5 degrees I think) and makes electricity whenever the sun's not blocked by clouds. 
There are 9 columns of 8 panels each, making 72 panels, which are each about 3 feet x 4 feet! 
Here's just one of the panels in the lower left-hand corner of the array. 
That little tag says BP Solar. I'm guessing that stands for British Petroleum, but it's just a guess. My friend's days of explaining anything have likely drawn to a close, so I'm not able to ask or get answers to any specific questions about this installation. I do know that it is grid-tied and he gets a "credit" each month instead of an electric bill. The house is on the order of 10,000 square feet, by the way and I'm sure the only reason he's getting that monthly credit is because he's spending his time 24/7 in a nursing home wondering who he is (memory problems!) and not using any electricity. In California (USA) when this puppy was installed, the state was giving away a state income tax credit, which would after 15 years or so make the thing FREE (or so the story goes--there's always a 'catch' it seems). That's about all I know. I posted it merely for general interest; hope everyone enjoys the look-see. . . . . . Mac 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 |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mack Thanks for the photos and sorry to hear about you friend, I look after Mother with the same problem although I have been able to stabilize her and she is maintaining a reasonable cognitive state without further deterioration for the last two years since I put her on rocket fuel. Those panels look like BP Solar 80 watt units and with 72 of them that's a serious solar array Should do around 25kw a day average if its on a mppt grid connect system. He should be getting a good credit on that though if its tax credits and he isn't paying any tax then it may be nothing. With our system here you get paid 44 cents KWH feed in rate, there are a few companies putting 10 to 30 KW Solar units up now and these give a return on investment of 26 percent better than the bank. $27 a day on a 10 kw system. That,s $8000 a year with a fifteen year government guarantee on the contract $126,000 at today's feed in rate and the way the price of energy is going it could double in that time. Food for serious thought All the best Bob Foolin Around |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Can we please pay a little more attention to detail? There are a LOT of people read articles like this who are already confused enough between watts, kilowatts, volt-amps kilovolt-amps, watt-hours, kilowatt-hours etc. Using the wrong terms in these posts is only making things that much worse because people see it written and "learn" their wrong terms as right, teaching others as they go. 72 modules of 80W each is nominally 5.7 KW peak output. That is, instantaneous power output. If there were 5 hours of full sun that would produce 28 kilowatt-hours (kWh). (Of course, the sun doesn't shine square on to them all the time, so there will be more hours of sun, some more oblique and making less power than others). In 8 "daylight" hours, your figure is likely close to the money - but the units are not. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Ross Ok Mate I am a little bit simplistic with my terms but to me all the definitions you mentioned are in real terms the same as a KW, is a thousand watts and all the rest are derivatives of that. I should have said a KWH I suppose but I tend to think that is understood, my mistake, and if not the question can be asked and then the learning process starts, we hope. I speak from experience of using these panels over a number of years and as they are a bit old tech now they are very reliable, I have some on my house 30 years old and still trickling away at around 70% of original power. Be careful you don't fall into your own trap as demonstrated by your use of the definition {instantaneous power output}, that has the connotation of producing 5.7 KW instantaneously. I know what you mean but others reading may be confused by this definition. As for the 80 watt panels I feel that is understood by all and sundry as the panel type, as we commonly refer to panels as 80 watt 100 watt 150 watt etc. If you get your electronic abacus out you will find that the panels don't produce their defined and stated output unless run at calibrated conditions , but we still refer to them as such. Thanks for you input on the subject as it will help to add interest to the subject. All the best Bob Foolin Around |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Yeah, those of us who use them all the time tend to automatically interpret the right units from the context. We do however, get a lot of people (particularly in IRC) for who the difference isn't so readily understood and they get horribly confused. It becomes even more evident when they're trying to size a system for their house. All these devices that say they want 300 watts, and 2 kilowatts etc - fine, but they just get so horribly confused when trying to size batteries for example - a fridge that takes 300W may consume 3 kWh in a day, and a 60W light globe could consume 1.4 kWh in a day or as little as .1 or less! Trying to explain that "watt hours" is simply watts consumed (or produced) times the number of hours it's used (produced) for. I know this is second nature to you, but not everyone "gets" it. Thats great, my BPs are only 6 years old and still producing close to full power. But they can - thats the entire point!! At any given instant, they can be producing 5.7 kilowatts. If they continue to do that for 3600 consecutive seconds, that'd be 5.7 kilowatt-hours. Indeed. 80W "nominal" normally with the panel at 25 degrees C and radiant power in the relevant part of the spectrum at 1000 watts per square metre, measured at the optimum power point. I frequenly see well OVER the nominal power out of my panels - on cloudy days, when the cloud-edge-effect produces well over the nominal 1000 watts per square metre illumination. Sadly, when the cloud shades the panels, output drops seriously. We need controllable clouds you can just park in the right place to enhance outputs! :) |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Ross I see over the rated output on my solar panels on a cool sunny day too but unfortunately it is the exception rather than the rule. Also with fixed panels you need nearly twice as many to get a reasonable daily solar yield. I live where there is 300 days a year sunshine so am fortunate that way. I think that the biggest con is the government solar initiative as it makes people think that a 1 or 1.5 KWh system will contribute to their power and give them a return on all the power fed back into the grid. My system puts in 5 KW a day in the summer and 1.5 KW a day in the winter, better than nothing but thats all. The main advantage was it didn't cost anything, so never look a gift horse in the mouth. The best part of the system is the solar HWS that saves 10 KW a day. Unfortunately this wasn't free but still a good investment. One good thing about the solar panels is that they are more reliable than the wind, so my wind turbine contributes only a little to the overall system. I have found over the years that it's not so much what you can generate from a solar system but what you can save on consumption that is the most important. My fridge was using 6+ KW a day due to design and old age so it was replaced with a new high efficiency one that uses 1.4 KW a day and lights have been replaced with led and CFL, for energy saving, not a lot of saving but every little bit helps, the pressure pump was replaced by a 12 volt pressure pump running of the 12 volt system that does lights and entertainment system. Let's hope that by a bit of banter about solar and the systems that support it we can generate enough interest to get an understanding of the systems advantages and pitfalls. All the best Bob Foolin Around |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Errr... 1 or 1.5 kW system. Not kWh system. kWh/day kWh/day kWh/day kWh/day Ahhh, so you're not just trying to wind me up by using the opposite terms, it's to generate discussion! <big grin> |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=MacGyver]I posted it merely for general interest; hope everyone enjoys the look-see. Yikes! 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 |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Ross 
We need active discussion mate sorry about that. All the best Bob Foolin Around |
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| BjBlaster Regular Member  Joined: 04/04/2008 Location: AustraliaPosts: 55 |
They are good panels.. I've got *one* of them and it very close to specified specs :) 
It charges my phone and runs the kiddies toys, so it *has* to be reliable. This 1 x BP panel has already exceeded the life/output rule of my "sunpower" panels supplied by the govt assisted solar install I have... It just goes to show quality vs sh*te is at play here :) Nice array by the way ;) Bj Check out my projects here in: Bj's Shed |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi BJ They are really good panels and stand the test of time, unfortunately the cost of making them in Australia cant compete with the Chinese ones, with just one to do a specific job like yours it is OK but when you need 30 or 69 panels it makes them just dear and prices out of the solar market for usable amounts of electricity to run the house or workshop. It will be interesting with the test of time on our grid feed subsidized systems. I suppose the best thing is to slowly stock up on better quality panels to augment the toy system available on the subsidy. It was sad to see your trees go like that, I had a few that are dropping branches to so had to do some trimming the worst are being replaced with fruit trees as a grow your own project. Also more wind turbine friendly than 25 meter giants. Had a look at your Webb site some very interesting stuff there, have you put some of it on the forum as I think there would be a lot of interest. Keep up the good work All the best Bob Foolin Around |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Ross I was thinking last night that it would be a good Idea to put together a set of Terms and definitions for solar so dummies like wont confuse the the newcomers with my illiterate terminology, with your definitive explanations, you would be the Ideal person for a short compilation of terms and references, what do you think? HE HE All the best' 'Bob Foolin Around |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
For What It's Worth I attended a social event (  ) yesterday and had a chat with my friend's wife (the friend who is in the nursing home) and she said she thought the solar panel array was rated at 10KW.
Maybe; maybe not, I dunno. . . . . . Mac 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 |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mack It could be as they rate systems in various ways it may be an annual average rating dependent on average sun exposure at that location. All the best Bob Foolin Around |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
The terms and definitions exist in *SO* many places already - but just where would they go here? A dry post in a new thread that rapidly drops off the bottom, never to be seen again? I'll kick something off when I get a few spare minutes, perhaps Glenn will find a spot for it. |
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| DTMC Newbie  Joined: 12/02/2010 Location: Posts: 11 |
Sub-forum called "Frequently Asked Questions" is usually the place. To prevent it becoming cluttered keep it locked and mods add worthwhile material from other threads as it arises. |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 573 |
VVK4AYQ wrote: It would be a good Idea to put together a set of Terms and definitions Ross wrote: I'll kick something off when I get a few spare minutes; perhaps Glenn will find a spot for it. Glenn I do agree with two long time members of this forum Dwyer the bushman |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All I had a good look through the forum today and think a set of terms and definitions regarding the different use of terms related watts would be good in information section as the few pieces of information I found to define what is needed, was as Ross said buried in the past topics, just a short set of definitions with the watts and time factors defined and explained for newcomers, as I for my part do not always define things as well as I should relying on an assumed understanding of the readers that may not be there, as Ross pointed out. All the best Bob Foolin Around |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
OK, lets all bash this about a bit and see if we can come up with a straightforward list of common terms, in a way that a newbie might actually understand! Terms and Definitions. Electrical. Volts. Voltage is a measure of the "pressure" of electrical energy, in the same way that water pressure is measured. The basic unit is the Volt. Larger voltages are expressed in kilo-volts (KV) and mega-volts (MV), while smaller voltages are expressed in milli-volts (mV) and micro-volts (uV). 1000uV = 1mV. 1000mV = 1V. 1000V = 1KV. 1000KV = 1MV. Amps. Amperage is a measure of the "flow" of electrical energy, in the same way that water flow is measured. The basic unit is the Amp or Ampere. Smaller currents usually expressed in milli-amps (mA) or micro-amps (uA), larger values in kilo-amps (KA). Watts. Watts are a measure of POWER. Watts are used in various fields, the term and the power are the same, but not necessarily immediately obviously so. Eg, a gas burner may be rated in watts or kilowatts. A 1000 watt gas burner will heat a room just as much as a 1000 watt electrical heater because they both produce the same power. In electrical terms, watts are generally the Volts times the Amps. A 12 Volt battery delivering 10 Amps is supplying 12*10 = 120 Watts. Watts are an instantaneous measure - that is, there is no time. A watt is a watt, for as long as you consume or produce it. In AC circuits, Watts may be much less than Volts*Amps. See PowerFactor. VA. Volt-Amps are similar to Watts. VA is usually only used in AC circuits. WattHours. Watt-Hours, and their more common big-brother KiloWatt-Hours are the most common way of expressing electrical WORK DONE. One watt being made or used constantly for one hour is one watt-hour. Remember, this is a measure of WORK DONE. If you go to work for a day, but spend 4 hours of it drinking coffee and reading the paper and the other 4 hours actually working, you have really done a half-a-day work. Same with watts. If you use one watt for half an hour, and nothing for the other half hour, you have only done a half-watt-hour of work. If you do nothing for half a day and work twice as hard for the other half, you've still only done one days work. So taking no power for half an hour and two watts for the other half hour is 1 watt-hour of work done. Smaller amounts of power are sometimes measured in watt-seconds PowerFactor. Power-factor is a moderately complex concept. In real AC circuits, a combination of resistance, inductance and capacitance exist. Inductance and capacitance have the effect of moving the current out of phase to the voltage resulting in less work being done than if current and voltage were perfectly in phase. Think of it like pushing a car. If you push it from directly behind, it's no to bad. If you push it sideways, you're exerting a lot of effort but the car isn't going anywhere. In between these two, sees you push the car diagonally - some of your effort goes into moving the car forwards while the rest is just wasted effort. Power factor is the measure of how "efficiently" your effort is being applied. It ranges from 0 (pushing directly sideways, with no useful work being done) to 1 (pushing directly in line, all the effort being useful work). Watts, in an AC circuit, is Volts * Amps * Powerfactor. |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
RossW Hey, thanks! I have a file I call "Oztule Saves" and it's where I save all John's wisdom. I've added a chapter to that document entitled "Techno-Dummy Electricity Basics" where I copied and pasted your 4m post. The more I learn, the more I realize I don't know. A basic "life's verse" I've held to is "I don't understand all I know about that." That verse covers a multitude of things, with electricity topping the list. Thanks again for taking the time to set the record straight. . . . . . Mac 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 |
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