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

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Posted by Eeyore on July 3, 2008, 4:10 am
Has anyone worked it out yet ?

I'm dying to hear the answer ! With or without battery storage and how
the 2 methods compare in cost.


Posted by Ron Rosenfeld on July 3, 2008, 12:01 pm
On Thu, 03 Jul 2008 05:10:11 +0100, Eeyore

Without some kind of storage, daily pumping won't be possible.  But the
recommendations made for number of panels, of the type specified by the OP,
and (at least in my case) optimally sited and positioned (fixed-tilt and
azimuth) are:

RR:  10 panels

GG: (1st try) 154 panels

GG: (2nd try)  17- 50W Panels

GG: (3rd try)  (C5 / C12) = 10.3 (11)

The OP has not posted back with any clarifying information, so it's hard to
speculate regarding storage.  If he were grid-connected, though, then
storage would be unnecessary and the number of panels could be sized based
on average annual insolation instead of worst month insolation, depending
on the economics of grid-tie in his location.

Posted by bealiba on July 4, 2008, 12:33 am
This is the indication of rons true (in)ability

"so it's hard to speculate regarding storage"

There is no speculation involved. If you know the daily load, which we
do (122.55Ah), the battery is sized to meet this load.

The daily load (122.55Ah) is a given. That is the pump as specified by
the OP.

The other given is the panels 50W (2.94A) also specified by the OP.

Every thing in between is a straight forward calculation.

Here is a bit of silliness to ponder;

Panels - inverter - no batteries:

Load 2500W
Inverter 85% efficient
Panels 2.6 A each(adjusted for real output)

The load  of 2500W at 12V(Panel voltage)  =  208 Amps

Adjusted for inverter inefficiency  = 244.7Amps

244.7 / 2.6 = 94.12 panels

Problem - Not enough to start pump. Pump requires ~ 5 times 2500 Watts
to start = 12500W

Adjusted for inverter inefficiency  = 14706 Watts (1225.5A)

1225.5A / 2.6A =

471.3 panels required.

Go on, add it up yourself.

It's as silly as a bent wheel, sure, but what a hoot. And it requires
only half an hours full sun a day.

Posted by wmbjkREMOVE on July 4, 2008, 2:23 pm
 On Thu, 3 Jul 2008 17:33:58 -0700 (PDT), bealiba@gmail.com wrote:

...only for those who don't have the experience to know about readily
available alternatives. For example, I'll be installing a 10gpm setup
for a friend soon. Array will be ~350W (depends on what modules are
available at best price) See curves for 11SQF-2 here
http://lib.store.yahoo.net/lib/wind-sun/SQFlex.pdf . Daily output will
be in the 3000 to 4500 gallon range (some 15 times the OP's volume
needs). So while you're busying yourself hilariously trying to fit
every application into your GIGO spreadsheet no matter how
inappropriately, normal people choose the best and most cost-effective
hardware to suit their application.

Only a true ghinius could start off with such a mind-bogglingly
moronic assumption. The rest of your calculations are equally idiotic.

Oh I see, this exercise was a transparent attempt to excuse your
original 154 panel recommendation. Lame. I hope you wasted lots of
time on it.

Your first and only response to embarrassment is always to try to
distract attention from your mistakes by writing ever more ridiculous
BS. Since your preference is to pretend that you're something you're
not, why not pretend to be a normal person, and simply own up to your

"The first rule of holes: When you're in one, stop digging."


Posted by bealiba on July 4, 2008, 11:27 pm
 On Jul 5, 12:23 am, wmbjkREM...@citlink.net wrote:

Sorry wayne, it remains a straight forward calculation. Only the
numbers change.

God help him.

Ah, the famous guess "Principle" Less than 350 Watts. What does the
pump actually use?

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How many watts does the pump draw?

The question was answered based on data provided.

2500(W)/12(V) = 208.33(A) rounded off to 208. No assumption involved.

Item was marked as "SILLINESS" to begin with. It seems that this is
necessary for you. Sorry you missed the point.

Tell us about your system. What are your loads? What do they draw? How
long are they run? And let's not forget, How does increasing the load
reduce resistance in conductors?

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