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Learning the difference
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| George Ghio 2007-06-14, 8:25 pm |
|
June 15, 2007
The danger of solar power information, and indeed information for any other pursuit, from the web
and/or news groups is a combination of self delusion, self aggrandizement and greed.
SELF DELUSION; This is a big trap for for many people. It works like this, a person decides that he
would like to use solar power. This person has a preconceived idea of solar power based on what they
have been told by someone in a pub, seen on TV or just wishful thinking. It really doesn’t matter
where the info comes from. What matters is that it is, nine times out of ten, utter nonsense. The
problem is that the person wants to believe this information. Why do they want to believe what is
patently rubbish. Well, the main reason is that it suits their idea of how things should work. They
want to believe that all they need is a golf cart battery and a couple of fifteen watt Harbor
Freight panels and they will have free power for life. It’s true, they will believe what makes them
feel good, and the truth will not be allowed to get in the way.
SELF AGGRANDIZEMENT; This often follows on from self delusion. Our person cobbles together a system
that will light his front porch or finds a system design in a magazine that looks wonderful and
copies it. In either case there is no regard for their real needs. No understanding of system design
or their loads what-so-ever. But, all of a sudden they are the undisputed masters of solar design.
Of course they must now share their expertise with anybody and everybody. They put up a web site to
share their considerable knowledge, others look at the site and become self deluded thus starting
down the path to becoming an expert in solar power. It is not long before there are hundreds or
thousands of experts in solar power selling the same golf cart battery and and HF panel fantasy to
other people who want to believe that you can be energy independent for a couple of hundred dollars.
GREED; This is a different beast all together. Usually this type of person starts out as a second
rate automotive - marine - golf cart battery salesman who all of a sudden discovers that there is
money to be made from self deluded wannabes in the solar game. He is usually still selling the same
old batteries but now they are, of course, just as good as the worlds best, at half the price. Just
stick ten or twenty in parallel and Bob’s your uncle. The only person to win is the battery
salesman, he has your money and you have a truck load of manure.
WHAT CAN YOU DO?
Well, you can learn about solar power design. The first thing to learn is that there is no great
magical art involved, just basic math skills and a willingness to accept that solar power is free,
but the equipment required to use it is not.
Second thing to learn is that if the person giving you sage advice can not put a watt hour figure to
every load in their system, it is highly unlikely that they know enough to be giving advice.
Third thing to learn is being able to tell the difference between 1) Look what I did, pat me on the
back, aren’t I a clever little boy, web sites and 2) those that offer real advice, using real
numbers, in a clear and precise way.
Fourth thing is that people who tout that any number of parallel strings of batteries are as good as
a single series string of cells, are totally out of their depth as far as home power systems are
concerned. If there is absolutely no other option then limit the number of parallel strings of
batteries to two.
Fifth, reduce your energy use. If you can’t knock a third off your energy use, you’re just not trying.
Sixth, Don’t come to a forum such as this one and ask:
“I have an average home, how much will solar power cost”.
It only excites the wannabes and starts a barrage of nonsense. If you must ask how much, at the very
least look at your last power bill, work out what you used for a single day and post that number.
But, OTOH, the better thing would be to get copy of a spreadsheet and put your number into it. And
of course the very best would be to do a complete energy audit of everything you want to run and use
the final number in your spreadsheet. A good spreadsheet will tell you how many panels and batteries
you will need in under two minutes. Then you can get on the net and find some prices.
--
Posted via a free Usenet account from http://www.teranews.com
| |
| merlin-7 2007-06-14, 9:25 pm |
| George
It may be true that your post is correct in many ways but you leave out a
great many things.
The first one is, many people need to start small and work their way up.
This is not the most cost effective way but It does work.
The way I look at it is, If someone installs a solar system (using golf
cart batteries or whatever) and they use it to run their porch light and
charge their cell phone, so be it. That's a few watts less used by burning
fossil fuels and they are learning.
I have no idea why you think that the HF 45 watt kit is bad...lets look at
it...
You get 2 5 watt cfls, 3 15 watt panels and the mounts for them ( I do hate
the charge controller but it does make a good distribution box) for a very
good price per watt of panels, the other items are just gravy.
As for paralleling batteries, It can be done but requires a lot more time.
Such as, Charging each set of batteries for 1 day a month by itself and
equalizing each set when needed) but it can be done, not the best way to do
it, but It can be done.
Lets look at you George...
Let me say first off that I have learned a good bit from you and am
thankful, that said. I do not understand why you always have negative
comments about people just starting out and the people tying to help them
with their first system. I think that everyone that wants to build their own
system should start out with a small set of panels, a small charge
controller and golfcart batteries or some other cheap battery. That way they
get to learn without investing a butt load of money into something they do
not understand.
George, I am here, to learn and to help others, when I can.
I do not, insult others or look down on anybody. I may make suggestions or
state a fact that I have learned from experience but I never insult.
I made many mistakes with my system but it always preformed the way I
expected it to, correcting the mistakes just improved it.
Some how, I have managed to keep my battery bank up and running for over 2
years with a wild mix of batteries . Two optima yellow tops (sealed) and a
D-4 wet cell. Granted I only have 350 watts of panels (including 3 HF 45
watt kits) I also have to equalize the wet cell once a month or so but It
does work. It is not the best set up, but it does work.
George, do you realize, That if everyone listened to you, no one would ever
try to start a small expandable solar system?
Something to think about...
Joe
As for
"George Ghio" <ghio@nobodyhome.com.au> wrote in message
news:4671cd25$0$24006$88260bb3@free.teranews.com...
>
> June 15, 2007
> The danger of solar power information, and indeed information for any
other pursuit, from the web
> and/or news groups is a combination of self delusion, self aggrandizement
and greed.
>
> SELF DELUSION; This is a big trap for for many people. It works like this,
a person decides that he
> would like to use solar power. This person has a preconceived idea of
solar power based on what they
> have been told by someone in a pub, seen on TV or just wishful thinking.
It really doesn’t matter
> where the info comes from. What matters is that it is, nine times out of
ten, utter nonsense. The
> problem is that the person wants to believe this information. Why do they
want to believe what is
> patently rubbish. Well, the main reason is that it suits their idea of how
things should work. They
> want to believe that all they need is a golf cart battery and a couple of
fifteen watt Harbor
> Freight panels and they will have free power for life. It’s true, they
will believe what makes them
> feel good, and the truth will not be allowed to get in the way.
>
> SELF AGGRANDIZEMENT; This often follows on from self delusion. Our person
cobbles together a system
> that will light his front porch or finds a system design in a magazine
that looks wonderful and
> copies it. In either case there is no regard for their real needs. No
understanding of system design
> or their loads what-so-ever. But, all of a sudden they are the undisputed
masters of solar design.
> Of course they must now share their expertise with anybody and everybody.
They put up a web site to
> share their considerable knowledge, others look at the site and become
self deluded thus starting
> down the path to becoming an expert in solar power. It is not long before
there are hundreds or
> thousands of experts in solar power selling the same golf cart battery and
and HF panel fantasy to
> other people who want to believe that you can be energy independent for a
couple of hundred dollars.
>
> GREED; This is a different beast all together. Usually this type of person
starts out as a second
> rate automotive - marine - golf cart battery salesman who all of a sudden
discovers that there is
> money to be made from self deluded wannabes in the solar game. He is
usually still selling the same
> old batteries but now they are, of course, just as good as the worlds
best, at half the price. Just
> stick ten or twenty in parallel and Bob’s your uncle. The only person to
win is the battery
> salesman, he has your money and you have a truck load of manure.
>
> WHAT CAN YOU DO?
>
> Well, you can learn about solar power design. The first thing to learn is
that there is no great
> magical art involved, just basic math skills and a willingness to accept
that solar power is free,
> but the equipment required to use it is not.
>
> Second thing to learn is that if the person giving you sage advice can not
put a watt hour figure to
> every load in their system, it is highly unlikely that they know enough to
be giving advice.
>
> Third thing to learn is being able to tell the difference between 1) Look
what I did, pat me on the
> back, aren’t I a clever little boy, web sites and 2) those that offer real
advice, using real
> numbers, in a clear and precise way.
>
> Fourth thing is that people who tout that any number of parallel strings
of batteries are as good as
> a single series string of cells, are totally out of their depth as far as
home power systems are
> concerned. If there is absolutely no other option then limit the number
of parallel strings of
> batteries to two.
>
> Fifth, reduce your energy use. If you can’t knock a third off your energy
use, you’re just not trying.
>
> Sixth, Don’t come to a forum such as this one and ask:
>
> “I have an average home, how much will solar power cost”.
>
> It only excites the wannabes and starts a barrage of nonsense. If you must
ask how much, at the very
> least look at your last power bill, work out what you used for a single
day and post that number.
> But, OTOH, the better thing would be to get copy of a spreadsheet and put
your number into it. And
> of course the very best would be to do a complete energy audit of
everything you want to run and use
> the final number in your spreadsheet. A good spreadsheet will tell you how
many panels and batteries
> you will need in under two minutes. Then you can get on the net and find
some prices.
>
> --
> Posted via a free Usenet account from http://www.teranews.com
>
| |
| George Ghio 2007-06-15, 3:25 am |
| merlin-7 wrote:
> George
> It may be true that your post is correct in many ways but you leave out a
> great many things.
>
> The first one is, many people need to start small and work their way up.
> This is not the most cost effective way but It does work.
Those that want to play with solar can do so. I'm talking about serious design and installation.
>
> The way I look at it is, If someone installs a solar system (using golf
> cart batteries or whatever) and they use it to run their porch light and
> charge their cell phone, so be it. That's a few watts less used by burning
> fossil fuels and they are learning.
Fine by me, except, after they get their porch lit they become an expert. Well, let's face it they
aren't. Not by any stretch if their imagination.
>
> I have no idea why you think that the HF 45 watt kit is bad...lets look at
> it...
> You get 2 5 watt cfls, 3 15 watt panels and the mounts for them ( I do hate
> the charge controller but it does make a good distribution box) for a very
> good price per watt of panels, the other items are just gravy.
15 Watt panels are toys. you buy them for your children to play with and perhaps learn something
>
> As for paralleling batteries, It can be done but requires a lot more time.
> Such as, Charging each set of batteries for 1 day a month by itself and
> equalizing each set when needed) but it can be done, not the best way to do
> it, but It can be done.
Of course it can be done. It is now and has always been and will continue to be the second best option.
>
> Lets look at you George...
>
> Let me say first off that I have learned a good bit from you and am
> thankful, that said. I do not understand why you always have negative
> comments about people just starting out and the people tying to help them
> with their first system. I think that everyone that wants to build their own
> system should start out with a small set of panels, a small charge
> controller and golfcart batteries or some other cheap battery. That way they
> get to learn without investing a butt load of money into something they do
> not understand.
Look, the plain and simple fact is that, there is just not that much to learn. Why people want solar
to be so mysterious is beyond me. Anybody can design a solar power system with nothing but the
correct formula and a calculator in around five minutes. And it will work.
>
> George, I am here, to learn and to help others, when I can.
Well, I'm sorry. But you help perpetrate the same old myths about batteries and design that do more
harm and cost people more money than if they just learned to use the correct formula.
>
> I do not, insult others or look down on anybody. I may make suggestions or
> state a fact that I have learned from experience but I never insult.
Good, you learned that parallel batteries work, and because they work and you use them you feel free
to tell others that it is a good idea.
>
> I made many mistakes with my system but it always preformed the way I
> expected it to, correcting the mistakes just improved it.
>
> Some how, I have managed to keep my battery bank up and running for over 2
> years with a wild mix of batteries . Two optima yellow tops (sealed) and a
> D-4 wet cell. Granted I only have 350 watts of panels (including 3 HF 45
> watt kits) I also have to equalize the wet cell once a month or so but It
> does work. It is not the best set up, but it does work.
You have built a system. This is not the same as sizing and designing a purpose built system to meet
a required load.
>
> George, do you realize, That if everyone listened to you, no one would ever
> try to start a small expandable solar system?
And a bloody good thing that would be. Small expandable systems are called toys. You are still in
the first category. You want to be right and you want to be seen as possessing knowledge. You lurch
from one poor solution to another with out benefit of an end goal.
Try this;
Do an energy audit that defines your final goal in kWh.
Get a copy of the correct formula or a spreadsheet. I will send you one if you like.
Compare the sized system to what you have now and see if what you have done so far is compatible and
able to be expanded to what you require for a price that is realistic compared to having just built
the system you need.
Something to think about.
>
> Something to think about...
>
> Joe
>
>
>
> As for
> "George Ghio" <ghio@nobodyhome.com.au> wrote in message
> news:4671cd25$0$24006$88260bb3@free.teranews.com...
> other pursuit, from the web
> and greed.
> a person decides that he
> solar power based on what they
> It really doesn’t matter
> ten, utter nonsense. The
> want to believe what is
> things should work. They
> fifteen watt Harbor
> will believe what makes them
> cobbles together a system
> that looks wonderful and
> understanding of system design
> masters of solar design.
> They put up a web site to
> self deluded thus starting
> there are hundreds or
> and HF panel fantasy to
> couple of hundred dollars.
> starts out as a second
> discovers that there is
> usually still selling the same
> best, at half the price. Just
> win is the battery
> that there is no great
> that solar power is free,
> put a watt hour figure to
> be giving advice.
> what I did, pat me on the
> advice, using real
> of batteries are as good as
> home power systems are
> of parallel strings of
> use, you’re just not trying.
> ask how much, at the very
> day and post that number.
> your number into it. And
> everything you want to run and use
> many panels and batteries
> some prices.
>
>
--
Posted via a free Usenet account from http://www.teranews.com
| |
|
|
> Fourth thing is that people who tout that any number of parallel strings of batteries are as good as
> a single series string of cells, are totally out of their depth as far as home power systems are
> concerned. If there is absolutely no other option then limit the number of parallel strings of
> batteries to two.
And just what principle are you claiming here?
> Sixth, Don't come to a forum such as this one and ask:
>
> "I have an average home, how much will solar power cost".
>
Why not? Just ask them what their light bill is or take a range of
light bills (say from $100/mo to $500/mo by $100 increments) and show
the PV system cost. You can figure what a PV system would need to be
to supply the same demand.
You need to add one more thing to your list of proponent traits:
ARROGANT SELF-CLAIMED EXPERT AVOIDER. That's the person who wants to
tell you how watches are made before he can tell you he doesn't know
what time it is because you haven't told him enough about your need to
know.
> It only excites the wannabes and starts a barrage of nonsense. If you must ask how much, at the very
> least look at your last power bill, work out what you used for a single day and post that number.
> But, OTOH, the better thing would be to get copy of a spreadsheet and put your number into it. And
> of course the very best would be to do a complete energy audit of everything you want to run and use
> the final number in your spreadsheet. A good spreadsheet will tell you how many panels and batteries
> you will need in under two minutes. Then you can get on the net and find some prices.
Or you could just say "I just did one for a guy who seemed pretty
average to me. He had an 1800sf house in eastern Oregon and it cost
$..... Next question?"
| |
|
| > Those that want to play with solar can do so. I'm talking about serious design and installation.
>
> Fine by me, except, after they get their porch lit they become an expert. Well, let's face it they
> aren't. Not by any stretch if their imagination.
>
> 15 Watt panels are toys. you buy them for your children to play with and perhaps learn something
>
And then he says:
>
> Look, the plain and simple fact is that, there is just not that much to learn. Why people want solar
> to be so mysterious is beyond me. Anybody can design a solar power system with nothing but the
> correct formula and a calculator in around five minutes. And it will work.
What's wrong with this picture?
>
>
>
> Of course it can be done. It is now and has always been and will continue to be the second best option.
And the first best option is?
>
>
> Well, I'm sorry. But you help perpetrate the same old myths about batteries and design that do more
> harm and cost people more money than if they just learned to use the correct formula.
And the correct formula is?
>
> Good, you learned that parallel batteries work, and because they work and you use them you feel free
> to tell others that it is a good idea.
And the better alternative is?
>
> You have built a system. This is not the same as sizing and designing a purpose built system to meet
> a required load.
Are we back to: "Look, the plain and simple fact is that, there is
just not that much to learn. Why people want solar to be so mysterious
is beyond me. Anybody can design a solar power system with nothing but
the correct formula and a calculator in around five minutes. And it
will work." ???
>
>
> And a bloody good thing that would be. Small expandable systems are called toys.
Of course they are. General Motors and Ford started business making
10,000 cars a day didn't they?
> You are still in
> the first category.
And GM and Ford and George have rendered the first category obsolete.
>
> Try this;
>
> Do an energy audit that defines your final goal in kWh.
This is the ARROGANT AVOIDER EXPERT tactic. Sell the analysis:
Final goal kWh isn't of much use if you don't know the demand pattern.
And I'll bet George's analysis does not reveal that. In fact I bet
nobody's does. I bet they just add a fudge factor to apply to the kWh
and hope for the best. And if they do that they might as well look at
the light bills and back calculate to kWh and do the same thing.
>
> Get a copy of the correct formula or a spreadsheet. I will send you one if you like.
You make a big deal about this formula: Is addition now called a
formula?
>
> Compare the sized system to what you have now and see if what you have done so far is compatible and
> able to be expanded to what you require for a price that is realistic compared to having just built
> the system you need.
>
> Something to think about.
Right ... and we've moved so much closer to the true answer to the
question haven't we?
| |
| Anthony Matonak 2007-06-15, 1:25 pm |
| Todd wrote:
>
> And then he says:
>
> What's wrong with this picture?
What's wrong with this is...
You read his post.
You responded to his post.
Anything past that gets lost in the noise.
Just as point of reference, most laptop computers use around 20 watts.
A single 15W panel would be enough to run a laptop a couple of hours a
day (more or less).
One could argue that "Laptops are toys. You buy them for your children
to play with and perhaps learn something." but that would be obviously
wrong.
We could compile an entire list of things you can do with a single 15W
solar panel but what would be the point? It won't make the newsgroup
any better. It'll only place us under attack and feed the trolls.
Anthony
| |
| wmbjkREMOVE@citlink.net 2007-06-15, 5:25 pm |
| On Fri, 15 Jun 2007 09:20:21 -0700, Anthony Matonak
<anthonym40@nothing.like.socal.rr.com> wrote:
>We could compile an entire list of things you can do with a single 15W
>solar panel but what would be the point? It won't make the newsgroup
>any better.
Sure it would. I bet a lot of people have seen the HF deal on those
cheap panels and wondered about practical uses. Heck, it doesn't even
need to be truly practical since many readers are looking for the
pleasure and education of doable solar. I still get that rush even
after 13 years of living off-grid. I sometimes stand in the shade of
an array during a break from fabricating, marveling at how cool it is
to be able to do so much a dozen miles from power lines. Same thing
when we're watching a good movie at night, with the turbine controller
dumping power even with a few hundred watts total load.
> It'll only place us under attack and feed the trolls.
One nitwit might complain, but obviously nobody is listening since
there's a steady stream of posters who've ignored his dopey criticisms
and gone ahead successfully with their projects. So if you have any
other ideas feel free to share them. Think of it this way - judging by
my email, some people read these groups *because* of the sturm und
drang. Your ideas might reach additional readers if they're posted in
one of those threads. ;-)
Wayne
| |
| merlin-7 2007-06-15, 8:25 pm |
| George means well....
He just has a problem with people just starting out in solar.
The way I look at it is.... get a hF 45 watt kit an optima deep cycle
(yellow top) a 4 amp charge controller and a small inverter.
If you do that...you will learn really quick as to what is involved in
larger solar systems without expending a lot of cash.
I ran my 2 meter ham radio and a 5 watt cfl on the above system for 6
months befor I expanded the system. It worked great.
You will learn more by hands on than by anybody telling you what you should
do...
My 2 cents
"Todd" <Todd@WithGLEE.com> wrote in message
news:1181920492.018098.27300@q69g2000hsb.googlegroups.com...
>
of batteries are as good as[color=darkred]
as home power systems are[color=darkred]
of parallel strings of[color=darkred]
>
> And just what principle are you claiming here?
>
>
>
> Why not? Just ask them what their light bill is or take a range of
> light bills (say from $100/mo to $500/mo by $100 increments) and show
> the PV system cost. You can figure what a PV system would need to be
> to supply the same demand.
>
> You need to add one more thing to your list of proponent traits:
>
> ARROGANT SELF-CLAIMED EXPERT AVOIDER. That's the person who wants to
> tell you how watches are made before he can tell you he doesn't know
> what time it is because you haven't told him enough about your need to
> know.
>
must ask how much, at the very[color=darkred]
day and post that number.[color=darkred]
put your number into it. And[color=darkred]
everything you want to run and use[color=darkred]
how many panels and batteries[color=darkred]
some prices.[color=darkred]
>
> Or you could just say "I just did one for a guy who seemed pretty
> average to me. He had an 1800sf house in eastern Oregon and it cost
> $..... Next question?"
>
>
| |
| George Ghio 2007-06-15, 8:25 pm |
| Todd wrote:
>
> And then he says:
>
> What's wrong with this picture?
Nothing. It is perfectly true. Anyone can size and design a solar power system.
>
>
> And the first best option is?
Single string series.
>
>
> And the correct formula is?
>
>
> And the better alternative is?
Single string series.
>
>
> Are we back to: "Look, the plain and simple fact is that, there is
> just not that much to learn. Why people want solar to be so mysterious
> is beyond me. Anybody can design a solar power system with nothing but
> the correct formula and a calculator in around five minutes. And it
> will work." ???
There is a difference. Wayne built a system.Then kept throwing money at it until it would meet his
energy demand, at least during daylight hours.
The other option is to design to the expected load and build a system that that works to spec from
the moment it is switched on.
>
>
> Of course they are. General Motors and Ford started business making
> 10,000 cars a day didn't they?
Not exactly the same thing but close enough, to increase production it was required that a new
assembly line be built.
>
>
> And GM and Ford and George have rendered the first category obsolete.
See above.
>
>
> This is the ARROGANT AVOIDER EXPERT tactic. Sell the analysis:
I'm not "selling" anything. It is all free to those who are willing to remove their head from their XXX.
>
> Final goal kWh isn't of much use if you don't know the demand pattern.
> And I'll bet George's analysis does not reveal that. In fact I bet
> nobody's does. I bet they just add a fudge factor to apply to the kWh
> and hope for the best. And if they do that they might as well look at
> the light bills and back calculate to kWh and do the same thing.
Crap. The demand pattern is a total nonsense in a well designed system. Over this 24 hour period X
kWh is consumed. If the system has the correct capacity who cares when the load is run.
Except for wayne who must needs do as much while the sun shines as he can.
>
>
>
> You make a big deal about this formula: Is addition now called a
> formula?
Well, 1+1 is a formula that yields the answer of 2.
But of course the formula for the sizing of a solar power system is a little bit more involved than
this. I can see that you may require help to understand it, but most people would be able to grasp
the basics in a few minutes.
>
>
> Right ... and we've moved so much closer to the true answer to the
> question haven't we?
Yes, use the correct formula to workout your required load in kWh at the beginning and use only
equipment that fits to the final solution and be prepared to dispose of a large part of this
equipment in the process of growing a system.
Far cheaper to just design and build the required system.
--
Posted via a free Usenet account from http://www.teranews.com
| |
| George Ghio 2007-06-15, 8:25 pm |
| Ah, the morning comics have arrived. Thank you wayne for brightening my day.
wmbjkREMOVE@citlink.net wrote:
> On Fri, 15 Jun 2007 09:20:21 -0700, Anthony Matonak
> <anthonym40@nothing.like.socal.rr.com> wrote:
>
>
>
> Sure it would. I bet a lot of people have seen the HF deal on those
> cheap panels and wondered about practical uses. Heck, it doesn't even
> need to be truly practical since many readers are looking for the
> pleasure and education of doable solar. I still get that rush even
> after 13 years of living off-grid. I sometimes stand in the shade of
> an array during a break from fabricating, marveling at how cool it is
> to be able to do so much a dozen miles from power lines. Same thing
> when we're watching a good movie at night, with the turbine controller
> dumping power even with a few hundred watts total load.
>
>
> One nitwit might complain, but obviously nobody is listening since
> there's a steady stream of posters who've ignored his dopey criticisms
> and gone ahead successfully with their projects. So if you have any
> other ideas feel free to share them. Think of it this way - judging by
> my email, some people read these groups *because* of the sturm und
> drang. Your ideas might reach additional readers if they're posted in
> one of those threads. ;-)
>
> Wayne
--
Posted via a free Usenet account from http://www.teranews.com
| |
|
| George Ghio <ghio@nobodyhome.com.au> wrote in
news:4672113a$0$32552$88260bb3@free.teranews.com:
[color=darkred]
> merlin-7 wrote:
>
> Those that want to play with solar can do so. I'm talking about
> serious design and installation.
Some people have no choice. I am probably 10 miles from the nearest
power line and i'm not loaded with cash to drop 10k+ on solar. I'm
adding to my system as I can afford to do so, and each addition lets me
run more stuff. Its easy to say 'build a perfect system first' but holy
crap.. spendy. I make my own panels from cells and add better/more
batteries as I can.
The real key is the hydro-electric setup hopefully going live once the
rains start after this summer. Then we'll have enough juice to run
anything! Screw solar in the winter man.
-z
| |
| philkryder 2007-06-16, 3:25 am |
| On Jun 14, 5:09 pm, George Ghio <g...@nobodyhome.com.au> wrote:
> June 15, 2007
> The danger of solar power information, and indeed information for any other pursuit, from the web
> and/or news groups is a combination of self delusion, self aggrandizement and greed.
>
> SELF DELUSION; This is a big trap for for many people. It works like this, a person decides that he
> would like to use solar power. This person has a preconceived idea of solar power based on what they
> have been told by someone in a pub, seen on TV or just wishful thinking. It really doesn't matter
> where the info comes from. What matters is that it is, nine times out of ten, utter nonsense. The
> problem is that the person wants to believe this information. Why do they want to believe what is
> patently rubbish. Well, the main reason is that it suits their idea of how things should work. They
> want to believe that all they need is a golf cart battery and a couple of fifteen watt Harbor
> Freight panels and they will have free power for life. It's true, they will believe what makes them
> feel good, and the truth will not be allowed to get in the way.
>
> SELF AGGRANDIZEMENT; This often follows on from self delusion. Our person cobbles together a system
> that will light his front porch or finds a system design in a magazine that looks wonderful and
> copies it. In either case there is no regard for their real needs. No understanding of system design
> or their loads what-so-ever. But, all of a sudden they are the undisputed masters of solar design.
> Of course they must now share their expertise with anybody and everybody. They put up a web site to
> share their considerable knowledge, others look at the site and become self deluded thus starting
> down the path to becoming an expert in solar power. It is not long before there are hundreds or
> thousands of experts in solar power selling the same golf cart battery and and HF panel fantasy to
> other people who want to believe that you can be energy independent for a couple of hundred dollars.
>
> GREED; This is a different beast all together. Usually this type of person starts out as a second
> rate automotive - marine - golf cart battery salesman who all of a sudden discovers that there is
> money to be made from self deluded wannabes in the solar game. He is usually still selling the same
> old batteries but now they are, of course, just as good as the worlds best, at half the price. Just
> stick ten or twenty in parallel and Bob's your uncle. The only person to win is the battery
> salesman, he has your money and you have a truck load of manure.
>
> WHAT CAN YOU DO?
>
> Well, you can learn about solar power design. The first thing to learn is that there is no great
> magical art involved, just basic math skills and a willingness to accept that solar power is free,
> but the equipment required to use it is not.
>
> Second thing to learn is that if the person giving you sage advice can not put a watt hour figure to
> every load in their system, it is highly unlikely that they know enough to be giving advice.
>
> Third thing to learn is being able to tell the difference between 1) Look what I did, pat me on the
> back, aren't I a clever little boy, web sites and 2) those that offer real advice, using real
> numbers, in a clear and precise way.
>
> Fourth thing is that people who tout that any number of parallel strings of batteries are as good as
> a single series string of cells, are totally out of their depth as far as home power systems are
> concerned. If there is absolutely no other option then limit the number of parallel strings of
> batteries to two.
>
> Fifth, reduce your energy use. If you can't knock a third off your energy use, you're just not trying.
>
> Sixth, Don't come to a forum such as this one and ask:
>
> "I have an average home, how much will solar power cost".
>
> It only excites the wannabes and starts a barrage of nonsense. If you must ask how much, at the very
> least look at your last power bill, work out what you used for a single day and post that number.
> But, OTOH, the better thing would be to get copy of a spreadsheet and put your number into it. And
> of course the very best would be to do a complete energy audit of everything you want to run and use
> the final number in your spreadsheet. A good spreadsheet will tell you how many panels and batteries
> you will need in under two minutes. Then you can get on the net and find some prices.
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com
George -
Help me to understand a bit better.
Suppose that I minimize my load and that I then carefully size my
installation.
Let's for example say that I need 70 kwh of capacity.
Suppose that I then obtain and install a single series string of
batteries to provide that capacity.
And, further suppose that I obtain the 8000watt of inverters needed
to meet the max instantaneous load with a reasonable "fudge factor"
for head room and motor start loads.
Suppose further that after a couple of years of successful operation
that "things change." New processes are added.
And, that I then need more capacity - suppose I need 100kwh capacity
and 10000 watts peak from my inverters.
Can I easily add additional batteries in series to reach the new
100kwh capacity?
Or, must I go to a new battery size for the entire installation?
What is the voltage limit that I can practically install in a single
series string?
Is there a practical limit to the input voltage to the inverters? If
so, what is it?
What do I do when my capacity needs cause the single string to exceed
the input voltage specs of the inverters?
Must all the batteries have similar cell capacity?
Or can I add some batteries with a smaller (or larger) capacity per
cell?
Thanks for your thoughts and experience.
Phil
| |
| Anthony Matonak 2007-06-16, 9:25 am |
| philkryder wrote:
....
> George -
I'm no George and I'm certainly no expert but I think I can point out
the most blatantly obvious stuff. 
> Let's for example say that I need 70 kwh of capacity.
> Suppose that I then obtain and install a single series string of
> batteries to provide that capacity.
....
> Suppose further that after a couple of years of successful operation
> that "things change." New processes are added.
> And, that I then need more capacity - suppose I need 100kwh capacity
> and 10000 watts peak from my inverters.
>
> Can I easily add additional batteries in series to reach the new
> 100kwh capacity?
> Or, must I go to a new battery size for the entire installation?
I've been told that it's not a good idea to mix old and new batteries.
Your best bet is to find a buyer or alternative use for the old cells
and get a new pack. Either that or another source of energy (like a
generator or wind turbine) to let you squeak by on the smaller than
needed batteries.
> What is the voltage limit that I can practically install in a single
> series string?
> Is there a practical limit to the input voltage to the inverters? If
> so, what is it?
The inverters are usually designed for a set input voltage. These are
usually 12V, 24V, 48V. Anything over 48V and I think some regulations
make life difficult. I'm not up on state of the art but I get the
impression you can't switch input voltages on most inverters. It's a
case of switching out the inverter for one with a higher input voltage.
> Must all the batteries have similar cell capacity?
> Or can I add some batteries with a smaller (or larger) capacity per
> cell?
Battery packs work best when they all match. If they don't match then
bad things happen, boiling batteries, cell reversal, early failure,
stuff like that.
With a system of that size, you're probably going to be hiring a
professional and they should be more than capable of figuring out ways
to help you upgrade. With more advanced technology it may be possible
to break your battery pack into smaller units or have paralleled
inverters, for instance. If you think you may need to do a major
upgrade in the future then planning for it up front can help a lot.
Anthony
| |
| George Ghio 2007-06-16, 9:25 am |
| philkryder wrote:
> On Jun 14, 5:09 pm, George Ghio <g...@nobodyhome.com.au> wrote:
>
> George -
>
> Help me to understand a bit better.
>
> Suppose that I minimize my load and that I then carefully size my
> installation.
>
> Let's for example say that I need 70 kwh of capacity.
Un-realistic but I'll play.
> Suppose that I then obtain and install a single series string of
> batteries to provide that capacity.
>
> And, further suppose that I obtain the 8000watt of inverters needed
> to meet the max instantaneous load with a reasonable "fudge factor"
> for head room and motor start loads.
>
> Suppose further that after a couple of years of successful operation
> that "things change." New processes are added.
> And, that I then need more capacity - suppose I need 100kwh capacity
> and 10000 watts peak from my inverters.
>
> Can I easily add additional batteries in series to reach the new
> 100kwh capacity?
No, and neither should you add a second string in parallel, unless you can find a set of batteries
that are of the same capacity and age(use) as the first string. Adding batteries to a series string
does not add capacity but increases voltage.
> Or, must I go to a new battery size for the entire installation?
That would be the best choice. It may be that batteries of the capacity may not be available so the
second best choice would be to run two parallel strings of lesser capacity and double your battery
maint.
>
> What is the voltage limit that I can practically install in a single
> series string?
The usual for home power would be 48V. I did meet a guy who had a 240volt system. Funny thing, he
had a bunch of batteries in his trailer at the time. He wouldn't say what he was doing with his
batteries but did mention that the ones in the trailer were to replace the ones that exploded in use.
> Is there a practical limit to the input voltage to the inverters? If
> so, what is it?
No, you can have an inverter custom built to suit. Most people would use 12 - 24 - 48 volts. The
rule of thumb is 12V for 1000Whrs 24V for 2000Whrs and 48V for 3000Whrs +. In reality these loads
will have a fair amount of gray area in actual use.
>
> What do I do when my capacity needs cause the single string to exceed
> the input voltage specs of the inverters?
See above. That said, it would not happen. You can add all the batteries you want to what ever
voltage but, you can only add capacity by using batteries with higher capacity. Changing the
capacity of a single string of series batteries will not change the voltage and adding batteries to
a single string will change the voltage but not add to the capacity.
>
> Must all the batteries have similar cell capacity?
No, they should be the "same" capacity to insure equal charging. That said I do know of a system, 23
- 840Ah and 1 - 1000Ah that still works but the 1000Ah is always undercharged. The owner is saving
for a new set of batteries. In a discussion such as this it would be wise to learn the difference
between cells and batteries.
> Or can I add some batteries with a smaller (or larger) capacity per
> cell?
Of course you can. I would suggest that you start a Christmas club account at the bank for the new
battery bank the same day you add your rogue cells.
>
> Thanks for your thoughts and experience.
>
> Phil
These are straight forward answers to your hypothetical question. Your question is a nonsense as far
as home power goes. As an industrial system, series - parallel batteries would be used. The charging
system would most likely cost more than the batteries and the batteries would be replaced as often
as every five years irregardless of their condition. It would all be written off on the taxes anyway.
Reality says;
70kWh/day
5 days autonomy
Battery capacity 12000Ah
Daily dod 13.5%
296 - 175W panels - 4 in series - 74 parallel strings.
--
Posted via a free Usenet account from http://www.teranews.com
| |
| wmbjkREMOVE@citlink.net 2007-06-16, 9:25 am |
| On Fri, 15 Jun 2007 20:46:41 -0400, "merlin-7" <merlin-7@sc.rr.com>
wrote:
>George means well....
When he first arrived in the group I thought he was a well-meaning
boob. I even emailed another poster asking him not to mock George
quite so much. But after watching him repeatedly write wild
exaggerations and outright lies about knowledgeable posters who'd
corrected his frequent and blatant errors, I came to the conclusion
that he'd washed out of his little solar biz for very good reason. The
course he took couldn't make up for the lack of experience and
critical thinking, which is why even after 20 years he's still limited
to answering the most basic questions and posting the same elementary
stuff over and over - info that one can read on any web site without
it being contaminated with goofy criticisms.
> He just has a problem with people just starting out in solar.
He has a problem with *everyone* who refuses to sign on to his tunnel
vision opinions. Doesn't matter if you're trying to charge some AAAs
or if you're one of the biggest solar outfits in the US. If you
correct George you'll get Ghioed until you shut up, which is as close
as he comes to accomplishment.
> The way I look at it is.... get a hF 45 watt kit an optima deep cycle
>(yellow top) a 4 amp charge controller and a small inverter.
> If you do that...you will learn really quick as to what is involved in
>larger solar systems without expending a lot of cash.
> I ran my 2 meter ham radio and a 5 watt cfl on the above system for 6
>months befor I expanded the system. It worked great.
> You will learn more by hands on than by anybody telling you what you should
>do...
> My 2 cents
I think that's true more often than not. For example, I've talked to a
couple of guys in the last year who pretty much refuse to do any math
no matter how much I encourage them. They both insist that their
personal experience will trump any planning, and they're mostly right.
They both have 48V Outback inverters and MX60s. So their systems are
easily expanded except for batteries which worse case can be sold and
replaced.
I've done it both ways - I did a lot of measuring and estimating
before moving off-grid or spending any money. But on the wind side I
bought a small turbine to try before investing in a tower. Right now I
have a new project in the works (for a friend) - a 24' tall,
free-standing tower than can hoist a ton and be packed in to remote
locations. There are several ways it could be done, but I think I'm
going to spend a day doing the initial work on the most instinctive
approach and then seen if I like it. I'm pretty sure the days labor
will get me farther along than trying to think of the all the pros and
cons of every alternative.
Wayne
| |
|
| On Jun 15, 7:17 pm, George Ghio <g...@nobodyhome.com.au> wrote:
> Todd wrote:
>
>
>
>
>
> Nothing. It is perfectly true. Anyone can size and design a solar power system.
You miss my point. Your first three comments are booga booga ....
don't try this yourself at home boys and girls.
You last comment is "this is all really trivial". So why the first
three comments?
>
>
>
>
>
> Single string series.
I have 10 12V batteries. Is single string series for this 120VDC? If
so, where do I find an inverter that takes 120VDC? If not, what is
"single string series"?
>
>
>
>
>
>
>
> Single string series.
COIK.
>
>
>
>
>
> There is a difference. Wayne built a system.Then kept throwing money at it until it would meet his
> energy demand, at least during daylight hours.
So this is just a spitting match between you and Wayne?
>
> The other option is to design to the expected load and build a system that that works to spec from
> the moment it is switched on.
You can write a spec and design and build to it perfectly ... and it
can fail because the spec was wrong. That's why even the most
knowledgeable engineers build pilot plants first.
>
>
>
>
>
> Not exactly the same thing but close enough, to increase production it was required that a new
> assembly line be built.
You miss the point again. Even if the auto manufactures had demand of
10,000 cars a day before opening their first plant, they couldn't have
opened a 10K car plant. They didn't have the knowledge. They couldn't
take the risk. In any endeavor, especially new ones, you walk before
you run.
>
>
>
>
>
> See above.
You see above!
>
>
>
>
>
>
> I'm not "selling" anything. It is all free to those who are willing to remove their head from their XXX.
You sure come off as if you're selling something ... if nothing more
than you are an expert and others should just behave and listen.
>
>
>
>
> Crap. The demand pattern is a total nonsense in a well designed system. Over this 24 hour period X
> kWh is consumed. If the system has the correct capacity who cares when the load is run.
Oh really? Try this: You are sawing wood remotely from 10:00AM to
2:00PM on sunny days only. You consume 5kWh on days you use the
system. What does the design look like?
Then try this: You are home only in the evening hours when there is no
PV output. You have a small modeling shop and run shop tools 6 hours
each evening. You also have normal micro wave, lighting, and home
entertainment demands. You consume 5kWh per day on average. What does
the design look like?
They're different aren't they?
>
> Except for wayne who must needs do as much while the sun shines as he can.
Right ... everyone has the same demand pattern except Wayne.
>
>
>
>
>
> Well, 1+1 is a formula that yields the answer of 2.
Right. But people not trying to impress with the complexity of their
knowledge base refer to that as addition rather than a formula.
>
> But of course the formula for the sizing of a solar power system is a little bit more involved than
> this. I can see that you may require help to understand it, but most people would be able to grasp
> the basics in a few minutes.
And how is it you can see that? So far, every illustration you have
given is simple addition?
>
>
>
>
>
>
> Yes, use the correct formula to workout your required load in kWh at the beginning and use only
> equipment that fits to the final solution and be prepared to dispose of a large part of this
> equipment in the process of growing a system.
See above. You admit that the demand pattern is not a concern, yet it
is a trivial exercise to show you are wrong.
>
> Far cheaper to just design and build the required system.
Actually, probably far more expensive. To design and build the
required system when you don't know what is required (which you have
demonstrated you don't) means you over design the system or it under
performs. An over designed system will always be more expensive than a
scalable system where you add components as you learn the requirements
through real experience. Further, learning by experience can avoid the
folly of buying an expensive PV system when a simple diesel driven
alternator charging the batteries can outperform it at a fraction of
the cost.
| |
| philkryder 2007-06-16, 1:25 pm |
| On Jun 16, 6:00 am, George Ghio <g...@nobodyhome.com.au> wrote:
> philkryder wrote:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> Un-realistic but I'll play.
>
>
>
>
>
> No, and neither should you add a second string in parallel, unless you can find a set of batteries
> that are of the same capacity and age(use) as the first string. Adding batteries to a series string
> does not add capacity but increases voltage.
>
>
> That would be the best choice. It may be that batteries of the capacity may not be available so the
> second best choice would be to run two parallel strings of lesser capacity and double your battery
> maint.
>
>
>
>
> The usual for home power would be 48V. I did meet a guy who had a 240volt system. Funny thing, he
> had a bunch of batteries in his trailer at the time. He wouldn't say what he was doing with his
> batteries but did mention that the ones in the trailer were to replace the ones that exploded in use.
>
>
> No, you can have an inverter custom built to suit. Most people would use 12 - 24 - 48 volts. The
> rule of thumb is 12V for 1000Whrs 24V for 2000Whrs and 48V for 3000Whrs +. In reality these loads
> will have a fair amount of gray area in actual use.
>
>
>
>
> See above. That said, it would not happen. You can add all the batteries you want to what ever
> voltage but, you can only add capacity by using batteries with higher capacity. Changing the
> capacity of a single string of series batteries will not change the voltage and adding batteries to
> a single string will change the voltage but not add to the capacity.
>
>
>
>
> No, they should be the "same" capacity to insure equal charging. That said I do know of a system, 23
> - 840Ah and 1 - 1000Ah that still works but the 1000Ah is always undercharged. The owner is saving
> for a new set of batteries. In a discussion such as this it would be wise to learn the difference
> between cells and batteries.
>
>
> Of course you can. I would suggest that you start a Christmas club account at the bank for the new
> battery bank the same day you add your rogue cells.
>
>
>
>
>
> These are straight forward answers to your hypothetical question. Your question is a nonsense as far
> as home power goes. As an industrial system, series - parallel batteries would be used. The charging
> system would most likely cost more than the batteries and the batteries would be replaced as often
> as every five years irregardless of their condition. It would all be written off on the taxes anyway.
>
> Reality says;
>
> 70kWh/day
>
> 5 days autonomy
>
> Battery capacity 12000Ah
>
> Daily dod 13.5%
>
> 296 - 175W panels - 4 in series - 74 parallel strings.
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com
Why do you say it is unrealistic?
I don't need 5 days autonomy, but rather only 2.
35kwh per day.
It sounds like if I need to "expand later," that I would need to
remove the existing setup and re-install.
Did you imply that or did I mis-understand?
thanks
Phil
| |
| philkryder 2007-06-16, 1:25 pm |
|
>
> I think that's true more often than not. For example, I've talked to a
> couple of guys in the last year who pretty much refuse to do any math
> no matter how much I encourage them. They both insist that their
> personal experience will trump any planning, and they're mostly right.
> They both have 48V Outback inverters and MX60s. So their systems are
> easily expanded except for batteries which worse case can be sold and
> replaced.
>
One of the reasons for being reluctant to make precise measurements
and calculations is that "thing happen."
As someone said, "prediction is terribly difficult, ESPECIALLY about
the FUTURE."
I want to have a system that is easily expandable, because operations
can change.
With a grid-tie system, one can let the grid carry extra load for "a
while".
With a generator system, FUEL costs dominate the long term costs
rather than CAPITAL costs. Therefore the system is easily scaled by
buying a new generator.
But consider what I must do with the series batteries that George
recommends.
I must "sell them all and get new ones all of which are the SAME
size."
Is it any wonder that folks are reluctant to jump in with both feet?
Is it any wonder that folks want to start small?
The problem is not the "error bars" on measurement or calculation.
The problem is the error bars on predicting the FUTURE.
And the massive size of each individual step in larger systems.
Of course, I really don't know.
I'm just inferring this from reading the posts and my own experience
with the past - which in my life was once the FUTURE.
Phil
| |
|
| > > Can I easily add additional batteries in series to reach the new
>
> No, and neither should you add a second string in parallel, unless you can find a set of batteries
> that are of the same capacity and age(use) as the first string. Adding batteries to a series string
> does not add capacity but increases voltage.
Wrong. Adding batteries, whether in series or in parallel, adds
capacity. Adding in series adds power capacity and voltage capacity.
Adding in parallel adds power capacity and current capacity. Buck and
boost DC-DC converters do the trading off of voltage for current and
vice versa and consume a little power for themselves in the process.
>
>
> That would be the best choice. It may be that batteries of the capacity may not be available so the
> second best choice would be to run two parallel strings of lesser capacity and double your battery
> maint.
Just what is the nature of this maintenance? I don't dispute that
adding batteries adds to maintenance. I'm just wondering how the
maintenance differs when adding in series or in parallel?
I also have a question regarding the batteries in series. I've done
some experimenting with 3 and 4 of my 12V batteries in series being
charged directly from my auto alternator putting out say 38V across
the 3 or 50V across the 4. The batteries are all identical and about
the same age. They are not all necessarily at the same potential to
start. I found 1 of the batteries would quickly get up to 15V before
the others and so I would have to throttle back letting the others
(say at only 12.5 to 13.5) catch up. What kind of control systems are
available to detect this condition and control it?
>
>
>
>
> The usual for home power would be 48V. I did meet a guy who had a 240volt system. Funny thing, he
> had a bunch of batteries in his trailer at the time. He wouldn't say what he was doing with his
> batteries but did mention that the ones in the trailer were to replace the ones that exploded in use.
So, what was he using as a 240+ volt source for charging? What was he
using for inverting that could take a 240V source?
>
>
> No, you can have an inverter custom built to suit.
And you think that's practical?
> Most people would use 12 - 24 - 48 volts. The
> rule of thumb is 12V for 1000Whrs 24V for 2000Whrs and 48V for 3000Whrs +. In reality these loads
> will have a fair amount of gray area in actual use.
What is the principle behind that rule of thumb? It seems to me a
better rule of thumb is to go as high in voltage as your charger and
inverter can support because the connecting wires are smaller and thus
the losses are lower. The downside is what you have to do to keep all
the cells in the system equalized.
>
>
>
>
> See above. That said, it would not happen.
I saw the above. And it would happen. You even state that getting a
custom built inverter is practical. Do you then have that custom built
inverter rebuilt? Of course not!
> You can add all the batteries you want to what ever
> voltage but, you can only add capacity by using batteries with higher capacity. Changing the
> capacity of a single string of series batteries will not change the voltage and adding batteries to
> a single string will change the voltage but not add to the capacity.
Again ... absolute nonsense. If I have a 1 12V battery, 70AH string I
have 840Wh. If I have a 2 12V battery string, each with 70AH capacity,
I have 1.68kWh. I have doubled my capacity. I have doubled my voltage
if I put them in series. I have doubled my current if I put them in
parallel.
>
>
>
>
> No, they should be the "same" capacity to insure equal charging. That said I do know of a system, 23
> - 840Ah and 1 - 1000Ah that still works but the 1000Ah is always undercharged. The owner is saving
> for a new set of batteries. In a discussion such as this it would be wise to learn the difference
> between cells and batteries.
It would also be important to bring into the discussion the issues of
equalizing battery cells when the batteries are in series vs when they
are in parallel!!!
>
>
> Of course you can. I would suggest that you start a Christmas club account at the bank for the new
> battery bank the same day you add your rogue cells.
>
>
>
>
>
> These are straight forward answers to your hypothetical question. Your question is a nonsense as far
> as home power goes. As an industrial system, series - parallel batteries would be used. The charging
> system would most likely cost more than the batteries and the batteries would be replaced as often
> as every five years irregardless of their condition. It would all be written off on the taxes anyway.
>
> Reality says;
>
> 70kWh/day
>
> 5 days autonomy
>
> Battery capacity 12000Ah
>
> Daily dod 13.5%
>
> 296 - 175W panels - 4 in series - 74 parallel strings.
COIK
| |
| clare at snyder.on.ca 2007-06-16, 8:25 pm |
| On Sat, 16 Jun 2007 09:30:20 -0700, Todd <Todd@WithGLEE.com> wrote:
>
>Wrong. Adding batteries, whether in series or in parallel, adds
>capacity. Adding in series adds power capacity and voltage capacity.
>Adding in parallel adds power capacity and current capacity. Buck and
>boost DC-DC converters do the trading off of voltage for current and
>vice versa and consume a little power for themselves in the process.
>
>
>Just what is the nature of this maintenance? I don't dispute that
>adding batteries adds to maintenance. I'm just wondering how the
>maintenance differs when adding in series or in parallel?
>
>I also have a question regarding the batteries in series. I've done
>some experimenting with 3 and 4 of my 12V batteries in series being
>charged directly from my auto alternator putting out say 38V across
>the 3 or 50V across the 4. The batteries are all identical and about
>the same age. They are not all necessarily at the same potential to
>start. I found 1 of the batteries would quickly get up to 15V before
>the others and so I would have to throttle back letting the others
>(say at only 12.5 to 13.5) catch up. What kind of control systems are
>available to detect this condition and control it?
>
If the batteries are identical and charged and discharged in series,
this will never happen. A "battery" is a number of cells in series.
Putting 2 12 volt (6 cell) "batteries" in series makes one 12 cell 24
volt battery. The cells will equalize on the first charge, and should
then stay equalized as they discharge and charge together.
Putting two 12 volt batteries in parallel makes 2 batteries.[color=darkred]
>
>So, what was he using as a 240+ volt source for charging? What was he
>using for inverting that could take a 240V source?
>
>
>And you think that's practical?
>
>
>What is the principle behind that rule of thumb? It seems to me a
>better rule of thumb is to go as high in voltage as your charger and
>inverter can support because the connecting wires are smaller and thus
>the losses are lower. The downside is what you have to do to keep all
>the cells in the system equalized.
>
>
>I saw the above. And it would happen. You even state that getting a
>custom built inverter is practical. Do you then have that custom built
>inverter rebuilt? Of course not!
>
>
>Again ... absolute nonsense. If I have a 1 12V battery, 70AH string I
>have 840Wh. If I have a 2 12V battery string, each with 70AH capacity,
>I have 1.68kWh. I have doubled my capacity. I have doubled my voltage
>if I put them in series. I have doubled my current if I put them in
>parallel.
>
>
>It would also be important to bring into the discussion the issues of
>equalizing battery cells when the batteries are in series vs when they
>are in parallel!!!
>
>
>COIK
>
--
Posted via a free Usenet account from http://www.teranews.com
| |
| George Ghio 2007-06-16, 8:25 pm |
| philkryder wrote:
> On Jun 16, 6:00 am, George Ghio <g...@nobodyhome.com.au> wrote:
>
> Why do you say it is unrealistic?
>
> I don't need 5 days autonomy, but rather only 2.
>
> 35kwh per day.
That is not quite what you said. What you said was;
"Let's for example say that I need 70 kwh of capacity."
Lack of useful information. Failure to us correct and complete information results in incorrect
sizing. If you want better results you will need better input information.
>
> It sounds like if I need to "expand later," that I would need to
> remove the existing setup and re-install.
> Did you imply that or did I mis-understand?
You failed to provide full and correct information. The answer is that you would need to replace
your battery bank (best solution) or double your battery bank with a parallel string of batteries of
the same capacity and age (second best solution).
The first solution would cost you less than the second because you would sell the first set of
batteries and offset the cost of the new set.
Please note that I have spent years trying to get people to realize the importance of using full and
correct figures in design of solar power systems. You preferred to listen to those who tell you what
you want to hear. Place yourself in category one. Being told what you want to hear makes you feel
good, listening to what is correct will make you feel better in the future.
>
> thanks
> Phil
>
>
>
--
Posted via a free Usenet account from http://www.teranews.com
| |
| George Ghio 2007-06-16, 8:25 pm |
| Todd wrote:
>
> Wrong. Adding batteries, whether in series or in parallel, adds
> capacity. Adding in series adds power capacity and voltage capacity.
> Adding in parallel adds power capacity and current capacity. Buck and
> boost DC-DC converters do the trading off of voltage for current and
> vice versa and consume a little power for themselves in the process.
six 12V - 100Ah batteries in series will be 100Ah at 12V
twelve 12V - 100Ah batteries in series will be 100Ah at 24V
>
>
> Just what is the nature of this maintenance? I don't dispute that
> adding batteries adds to maintenance. I'm just wondering how the
> maintenance differs when adding in series or in parallel?
More care is required to maintain correct charge in parallel sets of batteries
It is a geometric progression
2 Parallel strings - twice the maint.
3 parallel strings _ four times the maint.
>
> I also have a question regarding the batteries in series. I've done
> some experimenting with 3 and 4 of my 12V batteries in series being
> charged directly from my auto alternator putting out say 38V across
> the 3 or 50V across the 4. The batteries are all identical and about
> the same age. They are not all necessarily at the same potential to
> start. I found 1 of the batteries would quickly get up to 15V before
> the others and so I would have to throttle back letting the others
> (say at only 12.5 to 13.5) catch up. What kind of control systems are
> available to detect this condition and control it?
Several hours later they should all read the same (well as near as) if they don't then you have a
problem. Look at your connections to start with.
Many charge controllers have come and gone. The best charge controller is between your ears.
Unfortunately the user manual was lost in the mail.
>
>
> So, what was he using as a 240+ volt source for charging? What was he
> using for inverting that could take a 240V source?
If you remember, eh did not say what he was doing with his batteries.
>
>
> And you think that's practical?
It would depend on the application.
>
>
> What is the principle behind that rule of thumb? It seems to me a
> better rule of thumb is to go as high in voltage as your charger and
> inverter can support because the connecting wires are smaller and thus
> the losses are lower. The downside is what you have to do to keep all
> the cells in the system equalized.
Cost and efficiency. What you want and what's true are not the same thing.
>
>
> I saw the above. And it would happen. You even state that getting a
> custom built inverter is practical. Do you then have that custom built
> inverter rebuilt? Of course not!
If it was cost effective for the job then it is practical.
>
>
> Again ... absolute nonsense. If I have a 1 12V battery, 70AH string I
> have 840Wh. If I have a 2 12V battery string, each with 70AH capacity,
> I have 1.68kWh. I have doubled my capacity. I have doubled my voltage
> if I put them in series. I have doubled my current if I put them in
> parallel.
No you still have only 70Ah capacity.
>
>
> It would also be important to bring into the discussion the issues of
> equalizing battery cells when the batteries are in series vs when they
> are in parallel!!!
Equalizing batteries is part and parcel with owning and using them, A good reg will do the job on a
regular basis.
>
>
> COIK
>
>
--
Posted via a free Usenet account from http://www.teranews.com
| |
| George Ghio 2007-06-16, 8:25 pm |
| Ah, here it is a nice bright Sunday morning and the comics are delivered right on time, and in full
colour. Keep up the good work, I love a good laugh.
wmbjkREMOVE@citlink.net wrote:
> On Fri, 15 Jun 2007 20:46:41 -0400, "merlin-7" <merlin-7@sc.rr.com>
> wrote:
>
>
> When he first arrived in the group I thought he was a well-meaning
> boob. I even emailed another poster asking him not to mock George
> quite so much. But after watching him repeatedly write wild
> exaggerations and outright lies about knowledgeable posters who'd
> corrected his frequent and blatant errors, I came to the conclusion
> that he'd washed out of his little solar biz for very good reason. The
> course he took couldn't make up for the lack of experience and
> critical thinking, which is why even after 20 years he's still limited
> to answering the most basic questions and posting the same elementary
> stuff over and over - info that one can read on any web site without
> it being contaminated with goofy criticisms.
>
>
> He has a problem with *everyone* who refuses to sign on to his tunnel
> vision opinions. Doesn't matter if you're trying to charge some AAAs
> or if you're one of the biggest solar outfits in the US. If you
> correct George you'll get Ghioed until you shut up, which is as close
> as he comes to accomplishment.
>
>
> I think that's true more often than not. For example, I've talked to a
> couple of guys in the last year who pretty much refuse to do any math
> no matter how much I encourage them. They both insist that their
> personal experience will trump any planning, and they're mostly right.
> They both have 48V Outback inverters and MX60s. So their systems are
> easily expanded except for batteries which worse case can be sold and
> replaced.
>
> I've done it both ways - I did a lot of measuring and estimating
> before moving off-grid or spending any money. But on the wind side I
> bought a small turbine to try before investing in a tower. Right now I
> have a new project in the works (for a friend) - a 24' tall,
> free-standing tower than can hoist a ton and be packed in to remote
> locations. There are several ways it could be done, but I think I'm
> going to spend a day doing the initial work on the most instinctive
> approach and then seen if I like it. I'm pretty sure the days labor
> will get me farther along than trying to think of the all the pros and
> cons of every alternative.
>
> Wayne
--
Posted via a free Usenet account from http://www.teranews.com
| |
| George Ghio 2007-06-16, 8:25 pm |
| philkryder wrote:
>
> One of the reasons for being reluctant to make precise measurements
> and calculations is that "thing happen."
>
> As someone said, "prediction is terribly difficult, ESPECIALLY about
> the FUTURE."
>
> I want to have a system that is easily expandable, because operations
> can change.
You can have an expandable system, just leave out the word "easily"
>
> With a grid-tie system, one can let the grid carry extra load for "a
> while".
Of course.
>
> With a generator system, FUEL costs dominate the long term costs
> rather than CAPITAL costs. Therefore the system is easily scaled by
> buying a new generator.
Fuel will continue to rise in price. The sun will be the same price tomorrow as it was yesterday.
>
> But consider what I must do with the series batteries that George
> recommends.
>
> I must "sell them all and get new ones all of which are the SAME
> size."
Yes, and it is cheaper because you get back money for you old batteries, and make no mistake there
is a growing list of people who will pay good money for good second hand batteries.
> Is it any wonder that folks are reluctant to jump in with both feet?
> Is it any wonder that folks want to start small?
Look, if you want to start small, feel free. But if you don't know what you are building towards you
will probably never arrive.
>
> The problem is not the "error bars" on measurement or calculation.
> The problem is the error bars on predicting the FUTURE.
I predict that energy from sunlight will cost the same for the next several thousand years.
The equipment needed to use that energy will come down in the same period.
>
> And the massive size of each individual step in larger systems.
Ah, now it comes down to the real bugbear, fear of the unknown.
>
> Of course, I really don't know.
> I'm just inferring this from reading the posts and my own experience
> with the past - which in my life was once the FUTURE.
>
> Phil
>
>
>
>
>
--
Posted via a free Usenet account from http://www.teranews.com
| |
| George Ghio 2007-06-16, 8:25 pm |
| Todd wrote:
> On Jun 15, 7:17 pm, George Ghio <g...@nobodyhome.com.au> wrote:
>
> You miss my point. Your first three comments are booga booga ....
> don't try this yourself at home boys and girls.
You miss the point. Anybody can do it. And at home. And get it right. And save money in the long run.
>
> You last comment is "this is all really trivial". So why the first
> three comments?
The first comment is not to let your wishes get in the way of the truth
The second comment is to not let it go to your head when your head is in fact empty
The third comment is to beware of smooth talking salesmen who only want your money and will stroke
your ego to get it.
In short the whole point is that there is no great, dark magic about design of solar power systems.
Just true and correct numbers and a simple formula.
>
> I have 10 12V batteries. Is single string series for this 120VDC? If
> so, where do I find an inverter that takes 120VDC? If not, what is
> "single string series"?
10 X 12V is 120V.
Ask an inverter manufacture that specializes in large grid tied systems.
>
>
> COIK.
>
>
> So this is just a spitting match between you and Wayne?
>
>
> You can write a spec and design and build to it perfectly ... and it
> can fail because the spec was wrong. That's why even the most
> knowledgeable engineers build pilot plants first.
IF the spec is wrong. Then you got it wrong and need to learn your limits before you try again.
The first system I built for myself did not work properly. The fault was entirely my lack of
knowledge. This was more than twenty years ago, there was no one to guide me and I believed what
made me feel good rather than the facts.
>
>
> You miss the point again. Even if the auto manufactures had demand of
> 10,000 cars a day before opening their first plant, they couldn't have
> opened a 10K car plant. They didn't have the knowledge. They couldn't
> take the risk. In any endeavor, especially new ones, you walk before
> you run.
Yes, you walk through your house doing an energy audit, you walk through the correct formula, you
walk through selecting the correct equipment, walk through the installation and turn the system on
setting the parameters for the charge controller and inverter. Put your feet up and relax.
>
>
> You see above!
>
>
> You sure come off as if you're selling something ... if nothing more
> than you are an expert and others should just behave and listen.
You could say that I'm selling something. The price is $0.00
The product is your solar power system sizing and design. In short Knowledge that allows you to do it.
>
>
> Oh really? Try this: You are sawing wood remotely from 10:00AM to
> 2:00PM on sunny days only. You consume 5kWh on days you use the
> system. What does the design look like?
It looks just like the system I use, only larger. I cut wood maybe one day a week, the system runs
continuously day to day. If I am not there for a day, well, what does it matter.
>
> Then try this: You are home only in the evening hours when there is no
> PV output. You have a small modeling shop and run shop tools 6 hours
> each evening. You also have normal micro wave, lighting, and home
> entertainment demands. You consume 5kWh per day on average. What does
> the design look like?
Exactly the same.
>
> They're different aren't they?
No
>
>
> Right ... everyone has the same demand pattern except Wayne.
Yeah, pretty much.
>
>
>
>
> Right. But people not trying to impress with the complexity of their
> knowledge base refer to that as addition rather than a formula.
It is still a formula.
>
>
> And how is it you can see that? So far, every illustration you have
> given is simple addition?
Yeah, good isn't it, solar power is so simple it's amazing.
>
>
> See above. You admit that the demand pattern is not a concern, yet it
> is a trivial exercise to show you are wrong.
Is it really.
>
>
> Actually, probably far more expensive. To design and build the
> required system when you don't know what is required (which you have
> demonstrated you don't) means you over design the system or it under
> performs. An over designed system will always be more expensive than a
> scalable system where you add components as you learn the requirements
> through real experience. Further, learning by experience can avoid the
> folly of buying an expensive PV system when a simple diesel driven
> alternator charging the batteries can outperform it at a fraction of
> the cost.
The fact that you believe in a scalable system is just that you want it to be true. Put yourself in
category one.
--
Posted via a free Usenet account from http://www.teranews.com
| |
| philkryder 2007-06-17, 3:25 am |
| On Jun 16, 5:04 pm, George Ghio <g...@nobodyhome.com.au> wrote:
> philkryder wrote:
<snip>
>
> You failed to provide full and correct information. The answer is that you would need to replace
> your battery bank (best solution) or double your battery bank with a parallel string of batteries of
> the same capacity and age (second best solution).
>
> The first solution would cost you less than the second because you would sell the first set of
> batteries and offset the cost of the new set.
>
< snip >
How did I get a large enough inverter to meet the increased demand?
Wouldn't I need to replace the inverter as well?
| |
| Anthony Matonak 2007-06-17, 3:25 am |
| philkryder wrote:
> On Jun 16, 5:04 pm, George Ghio <g...@nobodyhome.com.au> wrote:
.... <snip stuff about increasing battery pack size> ...
>
> How did I get a large enough inverter to meet the increased demand?
> Wouldn't I need to replace the inverter as well?
You wouldn't need to change your inverter unless your instantaneous
power demand was higher. If the demand at any one moment was the
same but for a longer period of time, then you could stick with
the same inverter.
For example, (in simple numbers), say your need was for 7kW continuous
for 10 hours. This is 70kWh and you would need an inverter that could
put out 7kW. Now say you go to around 14 hours instead of 10. This
comes out to about 100kWh but you still only need 7kW at any one time.
Now say you stick with 10 hours but need 10kW continuous. This is still
100kWh but you'll need an inverter that can produce 10kW instead of 7kW.
Anthony
| |
| philkryder 2007-06-17, 1:25 pm |
| On Jun 16, 11:28 pm, Anthony Matonak
<anthony...@nothing.like.socal.rr.com> wrote:
> philkryder wrote:
>
> ... <snip stuff about increasing battery pack size> ...
>
>
>
>
> You wouldn't need to change your inverter unless your instantaneous
> power demand was higher. If the demand at any one moment was the
> same but for a longer period of time, then you could stick with
> the same inverter.
>
> For example, (in simple numbers), say your need was for 7kW continuous
> for 10 hours. This is 70kWh and you would need an inverter that could
> put out 7kW. Now say you go to around 14 hours instead of 10. This
> comes out to about 100kWh but you still only need 7kW at any one time.
> Now say you stick with 10 hours but need 10kW continuous. This is still
> 100kWh but you'll need an inverter that can produce 10kW instead of 7kW.
>
> Anthony
< unless your instantaneous
> power demand was higher.
Exactly - but that was the scenario that I was describing.
| |
| George Ghio 2007-06-17, 5:25 pm |
| philkryder wrote:
> On Jun 16, 5:04 pm, George Ghio <g...@nobodyhome.com.au> wrote:
>
> <snip>
> < snip >
>
> How did I get a large enough inverter to meet the increased demand?
>
> Wouldn't I need to replace the inverter as well?
>
>
>
>
>
>
Well Anthony has said it quite well, so all that's left to point out is:
"Welcome to the joys of an expandable system." Rather makes the point quite nicely. It takes very
careful planning to build a system that is expandable. Far better to plan ahead with a good idea of
what you want/need.
You are looking an an industrial power supply. That is big money. If you are not making big money
from the business then it is impracticable.
Solar energy is free, the equipment to use it is not.
--
Posted via a free Usenet account from http://www.teranews.com
| |
| philkryder 2007-06-17, 8:25 pm |
| On Jun 17, 2:38 pm, George Ghio <g...@nobodyhome.com.au> wrote:
> philkryder wrote:
>
>
>
>
>
>
> Well Anthony has said it quite well, so all that's left to point out is:
>
> "Welcome to the joys of an expandable system." Rather makes the point quite nicely. It takes very
> careful planning to build a system that is expandable. Far better to plan ahead with a good idea of
> what you want/need.
>
> You are looking an an industrial power supply. That is big money. If you are not making big money
> from the business then it is impracticable.
>
> Solar energy is free, the equipment to use it is not.
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com
Thanks George
It sounds like the implication, based on your insight and experience,
is that with current technology and economics, you believe that PV is
economical for "small" installations, but not for larger.
Is there some "sweet spot" that you have observed?
What is the Kwh size of that sweet spot?
Or am I again, misinterpreting?
Thanks again.
Phil
| |
| wmbjkREMOVE@citlink.net 2007-06-17, 8:25 pm |
| On Sun, 17 Jun 2007 22:33:52 -0000, philkryder <alt.google@Kryder.com>
wrote:
>It sounds like the implication, based on your insight and experience,
>is that with current technology and economics, you believe that PV is
>economical for "small" installations, but not for larger.
If you've been keeping up with the posts here you may have noticed
that there are folks with 6kW and larger setups who believe they've
made a sound investment.
>Is there some "sweet spot" that you have observed?
>What is the Kwh size of that sweet spot?
There's really no such thing as a sweet spot, each application is
different. Yours requires that 70+ kwh be generated during a 7 day
period and stored for use during 2 of those 7 days. That's about 50%
less energy than I make with 2 kW of tracking arrays and a 1 kW
turbine (contributes about 25% of the total) in a similar climate, so
your generating capacity will be similar as well. The difference is
that you need more than double the storage. Your choices at this point
are to make a better estimate of your consumption (it might be less
than you think), or whittle down your needs (new appliances or
whatever), or change to a combination of PV and generator etc. to
lessen the cost.
Even if you stick with the simplest make-it-and-store-it strategy, the
idea that you need 52kW of PV or even half that is pure lunacy. Since
you're obviously getting hopelessly confused here by conflicting
advice, I suggest that you spend a few minutes calling an independent
professional. Explain that you want 70 kWh (before losses) per week,
and perhaps 80 kWh of storage (keeping in mind that some of your
consumption won't be going through the batteries). The professional
will need to know exactly what climate zone you're in, and if he
doesn't ask then find someone else. Good data is readily available for
Santa Maria (only about 50 miles up the coast), so if you think your
location gets about the same amount of fog, tell the guy that and in
minutes he'll recommend an array capacity for fixed and tracking.
Beyond that he can help you decide if a turbine makes sense.
Here are some places you can call
http://store.solar-electric.com/info.html (AZ)
http://www.beyondoilsolar.com/contact_us.htm (CA)
Wayne
| |
|
| > >Just what is the nature of this maintenance? I don't dispute that
>
>
> If the batteries are identical and charged and discharged in series,
Identical batteries will never happen either. My batteries were
identical when I bought them. Discharging one and leaving a second
fully charged makes them non-identical.
> this will never happen.
Wrong. It "always" happens.
> A "battery" is a number of cells in series.
Well duh!
> Putting 2 12 volt (6 cell) "batteries" in series makes one 12 cell 24
> volt battery.
Well duh!
> The cells will equalize on the first charge, and should
> then stay equalized as they discharge and charge together.
Perhaps ... but while they're charging, the voltage across each
battery will be different. You can't just put 3 12-V batteries in
series and put 39V across the them and expect 13V across each battery.
One will leave the pack and get over 15V across it. You must then
lower the total voltage or you'll ruin that battery as you bring the
other two up to charge.
> Putting two 12 volt batteries in parallel makes 2 batteries.
Putting 2 12 volt batteries in series makes two batteries. There's a
voltage across each (nominally but not exactly 12V) and there's a
voltage across the pair (nominally and maybe exactly 24V. One could be
11.8V and the other 12.2 and there's nothing to force them to become
the same. This is exactly why you have to equalize the 6 cells in a
single 12V battery ... because over time and because the cells are in
series, some cells have a higher voltage than others. Equalizing
brings them all up to the same voltage.).
Putting 2 12 volt batteries in parallel makes two batteries. The only
way you can consider them one battery is to put their cells and
electrolyte together (and of course you don't do that). Putting 2 12V
batteries in parallel forces both batteries to be at the same
potential (nominally 12V). You then have 2 strings of 6 2V batteries
where the strings are in parallel.
| |
|
| On Jun 16, 7:23 pm, George Ghio <g...@nobodyhome.com.au> wrote:
> Todd wrote:
>
>
> six 12V - 100Ah batteries in series will be 100Ah at 12V
>
> twelve 12V - 100Ah batteries in series will be 100Ah at 24V
So far so good, George.
>
>
>
>
>
> More care is required to maintain correct charge in parallel sets of batteries
> It is a geometric progression
I asked what was the nature of the maintenance. If more care is
required, what is that care doing?
>
> 2 Parallel strings - twice the maint.
Doing what?
>
> 3 parallel strings _ four times the maint.
Doing what? And why is it climbing geometrically.
>
>
>
>
> Several hours later they should all read the same (well as near as) if they don't then you have a
> problem. Look at your connections to start with.
If that's the case, then why doesn't the voltage across each cell
remain the same when fully charged? Why do I have to go through a
monthly equilization exercise if not to coax each cell back to being
the same?
>
> Many charge controllers have come and gone. The best charge controller is between your ears.
> Unfortunately the user manual was lost in the mail.
If you're going to be insulting, you shouldn't be stupid at the same
time George.
>
>
>
>
>
> If you remember, eh did not say what he was doing with his batteries.
I didn't ask what he was doing with his batteries. I asked what he was
using to charge them. I then asked what he was using to tap that
charge (i.e. to invert from DC to AC). If you're going to be glib
George, at least pay attention.
>
>
>
>
>
> It would depend on the application.
Oh really? Name an application where you have a new custom inverter
built to suit as the demands change.
>
>
>
>
>
> Cost and efficiency. What you want and what's true are not the same thing.
George. You completely evade my question. I asked "what's the
principle behind that rule of thumb". And your answer just hangs out
in air. It neither addresses my question nor my statement. What are
you doing George?
>
>
>
>
>
> If it was cost effective for the job then it is practical.
And if it's not, you don't. And if it never is cost effective you
don't. Name a case where it's cost effective.
>
>
>
>
>
> No you still have only 70Ah capacity.
That's current capacity. But real battery capacity (or bank capacity)
is it's ability to store and deliver energy (power). And that power is
volts x current or watts. It stores charge. When that charge moves
over time it's called current. And when that move is caused by a
voltage differential it's called power. And battery capacity is both a
function of the charge it can deliver and voltage under which it
delivers it. Are you really this stupid George?
>
>
>
>
>
> Equalizing batteries is part and parcel with owning and using them, A good reg will do the job on a
> regular basis.
But equalization is complicated with a series string. You must assure
that no cell in the string gets too much voltage while the other cells
catch up. With batteries in parallel you never have more than 6 cells
in a string. With batteries in series (say 4 12V batteries), you now
have 24 cells in the string. It's more likely that some cells can be
overvoltaged when charging batteries in series than when charging them
in parallel.
>
| |
| philkryder 2007-06-18, 3:25 am |
| On Jun 17, 5:57 pm, wmbjkREM...@citlink.net wrote:
......
> Even if you stick with the simplest make-it-and-store-it strategy, the
> idea that you need 52kW of PV or even half that is pure lunacy....
> Wayne
Wayne - where did the 52kw of PV come from?
| |
| wmbjkREMOVE@citlink.net 2007-06-18, 9:25 am |
| On Mon, 18 Jun 2007 06:25:43 -0000, philkryder <alt.google@Kryder.com>
wrote:
>On Jun 17, 5:57 pm, wmbjkREM...@citlink.net wrote:
>.....
>
>
>Wayne - where did the 52kw of PV come from?
Ghio, June 16, 2007 - "296 - 175W panels - 4 in series - 74 parallel
strings" (51.8kW)
Here are some of his previous (and very typical) GIGO calculations.
Ghio, June 1, 2007 - "48 Volt system> 3500wh/day> 250Ah batteries
Total Ah demand 81.02 > Days Autonomy 2> Daily depth of discharge 33%
20 - 80W panels (1.6kW)"
Ghio, June 1, 2007 - "a bit over 2100 Ah and 128 - 80W panels"
(10.2kW)
Ghio, May 26, 2007 - "You are using 4kW hours a day" (you wrote 4kW
load for 7 hours on 3 days per week, which is an average of 12kWh per
day)
His recommendations thus far range from 1.6kW to 51.8kW. Now, even a
blind squirrel trips over a nut occasionally, so you could keep up the
current dialogue in the hope that he might eventually stumble onto the
right numbers. But how will you know if he does? Meanwhile
knowledgeable posters will be less likely to spend time helping you
when they can see that you value gibberish as highly as thoughtful
opinions.
As I said, if you're having trouble separating the outer space numbers
from the earthly ones, then you should get an opinion from a genuine
professional. Most of them will give you a preliminary estimate over
the phone for free. You might also go back and review Sylvan's
comments.
Wayne
| |
| George Ghio 2007-06-18, 5:25 pm |
| philkryder wrote:
> On Jun 17, 2:38 pm, George Ghio <g...@nobodyhome.com.au> wrote:
>
> Thanks George
>
> It sounds like the implication, based on your insight and experience,
> is that with current technology and economics, you believe that PV is
> economical for "small" installations, but not for larger.
Oh, Christ no. PV can be economical for any size system. But only the user can make the choice
according to their needs.
>
> Is there some "sweet spot" that you have observed?
> What is the Kwh size of that sweet spot?
There is always a sweet spot, but again it is subjective. The user must decide whether or not it is
worth the effort and/or co | | |