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How many panels ? ( to run 230 volt sprinkler pump 30 minutes a day?) - Page 18

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Posted by bealiba on July 17, 2008, 12:04 am

Ron, In my first reply I made it quite clear that there was not enough
information and suggested;

"Perhaps you would like to re-phrase the question. Do you envision the
use of batteries and inverter?"

In my second post I said;

"Best ditch the pump."

The whole idea of running a 2500W pump for half an hour off a PV
installation is ludicrous.

For a fraction of the money the OP could set up a farm windmill pump
and tank or even a solar pump and tank. Gravity still works.

But the problem is that the OP probably has a pumping set up in place
and wants to take it off grid.

You keep saying that I have suggested equipment. This is untrue. So
far in this discussion the only equipment suggested was by you. This
equipment being T105 batteries.

As far as the formula is concerned the only recommendation was the
minimum battery capacity.

Now, you have the formula, it requires user input. Can you do it? I
don't think you can. You talk the talk, but, you can't walk the walk.
I have already calculated the system. The thing is though, if I post
it now, you will whine and cry and carry on like a two bob watch. So,
you want to see my hand, put your cards on the table.

Posted by wmbjkREMOVE on July 17, 2008, 2:33 pm
On Wed, 16 Jul 2008 17:04:16 -0700 (PDT), bealiba@gmail.com wrote:

Yes, but *first* you supplied your mind-numbing calculations to
demonstrate that he needed 154 panels!

Yes, but only *after* you'd been corrected, and had read others'
recommendations to consider alternatives.

Baloney. Powering pumps with PV is done routinely, which you'd know if
you got out more. Lots of folks have the experience you lack, and have
written about it. Why not learn by reading that rather than making
idiotic declarations?

You don't know what you're talking about. Pressurizing water to normal
levels takes energy, and unless one has some scrounging ability or
whatever, they'll generally have to spend some serious money. The job
can't be accomplished by "gravity", or by one of your previous
nitwitted suggestions, solar suction. If you think it can be done "for
a fraction of the cost", then let's see you explain how, including
curves. Here, I'll supply the parameters  - 8gpm, 80ft of head. Now,
*exactly* what do you recommend, and how much will it cost?

The only "problem" here is that a nitwit has managed to turn a simple
question into a glaring advertisement for his lack of experience.

George Ghio, June 19/2008 "14 panels in series to give you 238V @ 3A
11 parallel strings to give you 2530A = 154 panels"
George Ghio, June 19/2008 "300Ah Battery 17- 50W Panels"
etc, etc.

... several times!

For a hundred posts you've been claiming that calculating this stuff
is "simple", and as usual you insist on proving it <snorf> by posting
multiple and variously wrong answers to a single question. But now
you're saying that you have yet *another* result that is finally
correct, except it's a secret. Too funny.

Reminds me of the time you backed yourself into a corner and demanded
non-disclosure agreements before you'd explain the secret solution.
You'll never learn.


Posted by Ron Rosenfeld on July 17, 2008, 6:55 pm
 On Wed, 16 Jul 2008 17:04:16 -0700 (PDT), bealiba@gmail.com wrote:

You made multiple recommnedations as to numbers of PV Panels.  Your last
one was for 11 panels with a particular specification:

Not so -- you recommended a minimum battery capacity at the 100 hr rate,
and also with a certain efficiency and maximum DOD levels.

I'll grant that you did not specify any makes or models of equipment, but
you did post specifications which you claimed would work.

If you have a real system that will work, and that also comes close to
meeting your previously posted specifications, I'd be very surprised.

GG specifications for battery bank:

B2      Maximum allowable depth of discharge = 70%
B13     Capacity of battery bank at 100 hr rate (B12 x B10) = 180
C4     Battery efficiency = 90%

GG specifications for panels:

C8      Selected module I at 14 volts at NOCT 2.94A
C9      Selected module nominal operating voltage. = 12V
C10     Guaranteed current (C8 x 0.9) = 2.65A
C11     Number of modules in series (A7 / C9) = 1
C12     Output per module (C10 x C6) = 13.2Ah
C13     Number of parallel strings of modules (C5 / C12) = 10.3

Specifically, I believe the battery you specify will have a MUCH larger
capacity at the 100 hr rate than the 180Ah you specified.

And I believe, if you stick with 50 watt panels, that the I at 14 volts at
NOCT will be very different from 2.94A.


Posted by Ron Rosenfeld on July 17, 2008, 7:09 pm
 On Wed, 16 Jul 2008 17:04:16 -0700 (PDT), bealiba@gmail.com wrote:

All the OP has provided is the pump specifications and how often he wants
to use it.  We don't know how much he is paying for electricity (although
PVWATTS says the state average is $.18USD per kWh).  If he needs to extend
the grid in order to use the pump, it might well be cost effective.

And as I wrote in my (only) response to the OP:

"But it should be clear that if you want to run your pump every day, you
will need some kind of storage ...

"You can store electricity, or you can store water.  Five days supply is
the usual recommendation.  If you store water, you'll need to have room for
a large enough tank.  But if you do that, you can use a different pump that
runs off DC, and not require batteries or an inverter.

A solar powered DC pump and water storage would make a lot more sense to me
than a windmill.

Posted by wmbjkREMOVE on July 17, 2008, 8:26 pm
 On Thu, 17 Jul 2008 15:09:26 -0400, Ron Rosenfeld

Second that. For submersible apps, a typical good-quality solar
installation is about $k (plus pipe etc.), or ballpark, pretty
similar to a conventional pump with batteries, inverter etc. For
small-demand applications the conventional setup is sometimes cheaper,
especially if it's part of a larger system. Once the demand increases,
the solar solution is more economical. But the wind alternative, at
least the old-fashioned high-torque Aeromotor setup, can easily be 3
times the price, *and* far more labor intensive to install and
maintain. http://www.deanbennett.com/windmill-catalog-page53.pdf  The
tower alone can cost more than the entire solar setup. Where the
ghinius ever got the idea that such things can cost "a fraction of the
money", is probably the same place where "gravity" can do the job. :-)
As hard as it is to imagine, I think he may be getting stupider with
each passing day.


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