Hybrid Car – More Fun with Less Gas

How many panels ? ( to run 230 volt sprinkler pump 30 minutes a day?) - Page 2

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Posted by Ron Rosenfeld on July 5, 2008, 11:55 am
 
On Thu, 3 Jul 2008 17:33:58 -0700 (PDT), bealiba@gmail.com wrote:


George is now adding mind-reading to his so-called talents.

He "knows" the OP will want *battery* storage, even though the OP did not
mention anything about the kind of storage that might be appropriate for
his application.  And also that he will want only 1 day of autonomy to run
his pump daily.

But even with regard to this assumption of his, note that GG writes the
following:

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

GG:  it remains a straight forward calculation.

  In a previous post, he figured one day of autonomy.

GG:
    12V system
    2250 Wh/day
    1 Day autonomy
    300Ah Battery
    66% Daily DOD
    5 PSH/Day
    17- 50W Panels

In another post, he is also recommending one day of autonomy, but comes up
with a different sized battery:

GG:
    B1     Number of days of autonomy = 1
    B6     Adjusted battery capacity (B3 / B5) = 180.5
    B9     A-hr capacity of selected battery = 180Ah
    B13     Capacity of battery bank at 100 hr rate (B12 x B10) = 180
    B14     Daily depth of discharge (100 x A8 / B13) = 68%
    B14     Daily depth of discharge (100 x A8 / B13) = 68%


It seems GG's "straight forward calculation" can give different results
depending on ... whimsy?

Same pump; same number of days of autonomy; two very different sized
batteries?
--ron

Posted by bealiba on July 5, 2008, 1:35 pm
 

Ron, you are telling a lie. Yes Same pump; same number of days of
autonomy;

Different number of Ahs. It seems that wayne is not the only one who
misquotes.

This is what was said;

A2      Daily load = 1250Wh
A4      Inverter Efficiency = 85%
A5      Account for inverter inefficiency - Load (A2/A4) = 1470.5
A7      System Voltage = 12
A8      Total A-hr demand per day (A5 / A7) = 122.55

B1      Number of days of autonomy = 1
B2      Maximum allowable depth of discharge = 70%
B3      Battery capacity (A8 x B1 / B2) = 175Ah
B4      Lowest 24 hour average temperature c
B5      Temperature correction factor =.97
B6      Adjusted battery capacity (B3 / B5) = 180.5
B7      Selected Battery
B8      Selected battery discharge rate 100
B9      A-hr capacity of selected battery = 180Ah
B10     Number of batteries in parallel (B6 / B9, rounded off) = 1
B11     Number of batteries in series (A7 / battery voltage) =1
B12     Check Capacity of selected battery at l00 Hr rate = 180
B13     Capacity of battery bank at 100 hr rate (B12 x B10) = 180
B14     Daily depth of discharge (100 x A8 / B13) = 68%

This is correct and everyone can follow the calculation step by step.
There is nothing hidden.

You're not fooling anybody.

Posted by Ron Rosenfeld on July 6, 2008, 2:48 am
 On Sat, 5 Jul 2008 06:35:05 -0700 (PDT), bealiba@gmail.com wrote:


George,

Since it was you who specified different battery sizes given the same
question by the OP, it is clear who is being disingenuous.

You know, if you spent a fraction of the time educating yourself and
researching your stuff as you do trying to cover up your errors, you might
actually learn something worthwhile.

What data source did you use to get your values for what seems to be your
most recent guess at an acceptable system (11 - 50Watt panels and a 180Ah
battery)?

The data I have for Kilauea show that for 50 watt panels with a NOCT of
45.2C, temperature coeff of power of -0.5%/C, and an efficiency of 13% at
STC, that your recommendation of 11 panels and 180AH of battery storage
will result in a shortened battery life and a significant capacity
shortage.

I didn't have the figures for your 180Ah battery, so I used Trojan T-105
which have a 225 Ah capacity, a minimum state of charge of 30% and an 85%
efficiency. However, to make it more compatible with your 180Ah battery, I
changed the efficiency to 90%.

With 11 panels and 2 "Ghio-modifed" T-105's in series, there is a capacity
shortage of 23% over the course of a year, and battery life is 42% of what
it would be with an optimal system.  It is also more expensive than the
optimal system.

I suppose you will now try to explain how your 180Ah battery will prevent
the shortfall and have an improved battery life compared with a 225Ah
battery, that has the same allowable depth of discharge and efficiency.  Or
maybe you'll just revert to type and continue with your insults <sigh>.
--ron

Posted by bealiba on July 6, 2008, 3:01 am
 
You told a lie and got caught.

I learned that you will misquote, quote out of context and tell
outright lies.

Watts and panels from OP.

Show us the numbers. OH, sorry, I forgot, you're an idiot and can't
prove any claim you might make

Ah yes. The T105 Trojan, Trojan make condoms, don't they? Your amateur
status is showing.

Show us the numbers. OH, sorry, I forgot, you're an idiot and can't
prove any claim you might make. Damn, I did it again.

180Ah is the correct capacity for the job. You have yet to prove it
wrong.



Posted by bealiba on July 6, 2008, 6:11 am
 While we wait for ron's next tirade of nonsense let's see what happens
when we change the battery capacity to 225 Ahs.

Same formula, same data with the battery capacity changed to 225Ahs at
B9, which funnily enough is labeled "A-hr capacity of selected
battery". The reason for this label is that this is where "YOU" get to
specify the battery you choose to use. You see, while ron whinges
about the calculated minimum battery size, "YOU" get to specify "YOUR"
requirements within the formula. The only proviso is thet you do not
change any of the actual calculations.


A2      Daily load = 1250Wh
A4      Inverter Efficiency = 85%
A5      Account for inverter inefficiency - Load (A2/A4) = 1470.5
A7      System Voltage = 12
A8      Total A-hr demand per day (A5 / A7) = 122.55

B1      Number of days of autonomy = 1
B2      Maximum allowable depth of discharge = 70%
B3      Battery capacity (A8 x B1 / B2) = 175Ah
B4      Lowest 24 hour average temperature c
B5      Temperature correction factor =.97
B6      Adjusted battery capacity (B3 / B5) = 180.5
B7      Selected Battery
B8      Selected battery discharge rate 100
B9      A-hr capacity of selected battery = 225Ah
B10     Number of batteries in parallel (B6 / B9, rounded off) = 1
B11     Number of batteries in series (A7 / battery voltage) =1
B12     Check Capacity of selected battery at l00 Hr rate = 225
B13     Capacity of battery bank at 100 hr rate (B12 x B10) = 225
B14     Daily depth of discharge (100 x A8 / B13) = 54.47%

And there you have it, the Daily depth of discharge has dropped to
54.47%

C1      Design tilt
C2      Design month
C3      Total energy demand per day (A8) 2.55Ah
C4      Battery efficiency = 90%
C5      Array output required per day (C3 / C4) = 136.2
C6      Peak sun hours at design tilt for design month = 5
C7      Selected module
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

This formula is correct and will correctly size a stand alone PV
system. Neither Tweedledee nor Tweedledum can prove otherwise. Of
course they will keep saying it is incorrect, but never a shred of
mathematical proof will ever be forthcoming.

Of course there is still the problem of designing for an autonomy of
only one day. It is more common to design for several days autonomy.

So let's up the ante and change the system for 5 days autonomy. We
will keep the Trojans so we can clearly see the change;


A2      Daily load = 1250Wh
A4      Inverter Efficiency = 85%
A5      Account for inverter inefficiency - Load (A2/A4) = 1470.5
A7      System Voltage = 12
A8      Total A-hr demand per day (A5 / A7) = 122.55

B1      Number of days of autonomy = 5
B2      Maximum allowable depth of discharge = 70%
B3      Battery capacity (A8 x B1 / B2) = 875.35Ah
B4      Lowest 24 hour average temperature c
B5      Temperature correction factor =.97
B6      Adjusted battery capacity (B3 / B5) = 902.42
B7      Selected Battery
B8      Selected battery discharge rate 100
B9      A-hr capacity of selected battery = 225Ah
B10     Number of batteries in parallel (B6 / B9, rounded off) = 4
B11     Number of batteries in series (A7 / battery voltage) =1
B12     Check Capacity of selected battery at l00 Hr rate = 225
B13     Capacity of battery bank at 100 hr rate (B12 x B10) = 900
B14     Daily depth of discharge (100 x A8 / B13) = 13.62%

C1      Design tilt
C2      Design month
C3      Total energy demand per day (A8) 2.55Ah
C4      Battery efficiency = 90%
C5      Array output required per day (C3 / C4) = 136.2
C6      Peak sun hours at design tilt for design month = 5
C7      Selected module
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



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