Posted by *bealiba* on July 22, 2008, 12:49 pm

*> On Mon, 21 Jul 2008 19:36:54 -0700 (PDT), beal...@gmail.com wrote:*

*> >Again. The 180Ah is the minimum battery capacity required. NOT a*

*> >battery recommendation.*

*> >The formula requires the user to input data for chosen equipment. YOU*

*> >chose T105s for the battery but were unable to supply the rest of the*

*> >required information.*

*> No, I asked you if the T105, which has more than a 180Ah capacity at 100*

*> hrs, would work in your system. As usual, you waffled.*

No, you suggested the T105s and failed to provide the fill specs for

the sizing.

*> >I never recommended a battery.*

*> Good thing for the OP and anyone else reading.*

*> That's because one does not exist that meets the specifications *YOU* put*

*> into *YOUR* sizing formula spreadsheet and would work for the OP's system*

*> (180Ah at the 100 hr rate).*

The 180 Ah is the minimum battery capacity required, not a battery

recommendation. At the required half hour discharge rate the minimum

battery capacity is still 180AH.

*> You also didn't recommend a particular panel, again for the same reason:*

*> *YOU* could not find a panel that would meet the specifications *YOU* put*

*> into *YOUR* sizing formula spreadsheet that could work in the OP's system*

*> (I at 14V at NOCT 2.94A).*

Ya gotta laugh. User information required, the user supplies the specs

for the panel. You pick a panel and put its specs into the formula. if

you prefer I at 17V at NOCT 2.94A. Use it.

*> What you did show was your lack of knowledge about how batteries work, and*

*> how solar panels are rated; as well as what is required for a working*

*> system.*

What I did show is the correct formula for sizing a stand alone solar

PV system. That was my only intent. You have failed to supply true and

correct specs.This is not surprising in the least. You have no concept

of what is actually required for the correct sizing of a system.

The information supplied by the OP was just enough to calculate the

minimum battery capacity. Nothing more.

To seriously try to size a system to supply 2500 W for a half hour is

a waste of time. To attempt to build said system is a waste of money.

The formula is correct, you can't prove otherwise.

Posted by *Ron Rosenfeld* on July 22, 2008, 1:33 pm

On Tue, 22 Jul 2008 05:49:47 -0700 (PDT), bealiba@gmail.com wrote:

*>What I did show is the correct formula for sizing a stand alone solar*

*>PV system. That was my only intent. You have failed to supply true and*

*>correct specs.This is not surprising in the least. You have no concept*

*>of what is actually required for the correct sizing of a system.*

*>> That's because one does not exist that meets the specifications *YOU* put*

*>> into *YOUR* sizing formula spreadsheet and would work for the OP's system*

*>> (180Ah at the 100 hr rate).*

*>The 180 Ah is the minimum battery capacity required, not a battery*

*>recommendation. At the required half hour discharge rate the minimum*

*>battery capacity is still 180AH.*

It is sad that, after all so many people have been trying to teach you, you

can still spout the same old drivel.

*>The information supplied by the OP was just enough to calculate the*

*>minimum battery capacity. Nothing more.*

And you couldn't even do that correctly.

*>>To seriously try to size a system to supply 2500 W for a half hour is*

*>a waste of time. To attempt to build said system is a waste of money.*

Certainly your widely disparate results have proven that that is the case,

for you.

*>The formula is correct, you can't prove otherwise.*

Since it gives incorrect results, there's no need. And since you can't

even understand your errors, there's no point.

--ron

Posted by *bealiba* on July 23, 2008, 11:43 pm

*> On Tue, 22 Jul 2008 05:49:47 -0700 (PDT), beal...@gmail.com wrote:*

*> >What I did show is the correct formula for sizing a stand alone solar*

*> >PV system. That was my only intent. You have failed to supply true and*

*> >correct specs.This is not surprising in the least. You have no concept*

*> >of what is actually required for the correct sizing of a system.*

*> >> That's because one does not exist that meets the specifications *YOU* put*

*> >> into *YOUR* sizing formula spreadsheet and would work for the OP's system*

*> >> (180Ah at the 100 hr rate).*

*> >The 180 Ah is the minimum battery capacity required, not a battery*

*> >recommendation. At the required half hour discharge rate the minimum*

*> >battery capacity is still 180AH.*

*> It is sad that, after all so many people have been trying to teach you, you*

*> can still spout the same old drivel.*

*> >The information supplied by the OP was just enough to calculate the*

*> >minimum battery capacity. Nothing more.*

*> And you couldn't even do that correctly.*

The correct minimum battery capacity is 180Ahs. IF you feel that this

is not correct you can try to prove it wrong.

*> >>To seriously try to size a system to supply 2500 W for a half hour is*

*> >a waste of time. To attempt to build said system is a waste of money.*

*> Certainly your widely disparate results have proven that that is the case,*

*> for you.*

*> >The formula is correct, you can't prove otherwise.*

*> Since it gives incorrect results, there's no need. And since you can't*

*> even understand your errors, there's no point.*

Ah, a point, yes indeed. The point is that the formula is correct. The

minimum battery capacity is correct. You have yet to prove otherwise.

The problem here is that unless you have someone to hold your hand

throughout the process of system sizing you are simply unable to do

it. You need to be led by the hand through each step. Every little

piece if information spoon fed to you. Between you, Tweedledee, and

your bunk mate Tweedledum, who thinks that increasing the load will

reduce voltage drop, it is hard to tell which of you is the more

incompetent.

To those that have been watching this bit of street theater, the

formula is correct. BUT be aware, you need to supply an amount of

actual equipment specifications to use the formula. If you are

unwilling to provide this information then you would be better off to

hire someone to design your system.

Lets look at what Tweedledeed cant manage. i.e. User Input

Daily Load - 4250AH

System Voltage - 48V

A2 Daily load = 4250Wh - User Input

A4 Inverter Efficiency = 90% - User Input

A5 Account for inverter inefficiency - Load (A2/A4) = 4722Wh

A7 System Voltage = 48 - User Input

A8 Total A-hr demand per day (A5 / A7) = 122.55

B1 Number of days of autonomy = 5 - User Input

B2 Maximum allowable depth of discharge = 70% - User Input

B3 Battery capacity (A8 x B1 / B2) = 702.71Ah

B4 Lowest 24 hour average temperature =10c - User Input

B5 Temperature correction factor =.96 - User Input

B6 Adjusted battery capacity (B3 / B5) = 731.99

B7 Selected Battery - AS770 - User Input

B8 Selected battery discharge rate 120 - User Input

B9 A-hr capacity of selected battery = 840Ah - User Input

B10 Number of batteries in parallel (B6 / B9, rounded off) = 1

B11 Number of batteries in series (A7 / battery voltage) =24

B12 Check Capacity of selected battery at l20 Hr rate = 840 - User

Input

B13 Capacity of battery bank at 120 hr rate (B12 x B10) = 840

B14 Daily depth of discharge (100 x A8 / B13) = 11.71%

C1 Design tilt - 45 degrees - User Input

C2 Design month - June - User Input

C3 Total energy demand per day (A8) =98.38Ah

C4 Battery efficiency = 90% - User Input

C5 Array output required per day (C3 / C4) = 109.31

C6 Peak sun hours at design tilt for design month = 5 - User

Input

C7 Selected module - BP 4175 - User Input

C8 Selected module I at 35.4 volts at NOCT 4.9A - User Input

C9 Selected module nominal operating voltage. = 24V - User Input

C10 Guaranteed current (C8 x 0.9) = 4.41A

C11 Number of modules in series (A7 / C9) = 2

C12 Output per module (C10 x C6) = 22.05Ah

C13 Number of parallel strings of modules (C5 / C12) = 5.51

I have marked all the points of user input. In all, there are 18

points where Tweedledee is out of his depth.

This formula does not take I have an average house as an argument.

The user must be prepared to supply the required information. If the

user is not prepared to do this work, then he or she should find a

designer in the phone book, say yes to everything the designer

suggests and hope that when something breaks the designer will show up

to fix it.

Posted by *Ron Rosenfeld* on July 24, 2008, 2:01 am

On Wed, 23 Jul 2008 16:43:15 -0700 (PDT), bealiba@gmail.com wrote:

*>The correct minimum battery capacity is 180Ahs. IF you feel that this*

*>is not correct you can try to prove it wrong.*

You wouldn't understand the proof. Your ignoring previous postings as well

as your ongoing piffle is evidence enough of that.

Again George demonstrates his lack of knowledge of battery chemistry, and

cannot even quote what he wrote correctly!

What George wrote in his specifications:

*> B2 Maximum allowable depth of discharge = 70% *

*> B13 Capacity of battery bank at 100 hr rate (B12 x B10) = 180*

*> C4 Battery efficiency = 90%*

And George expects a battery bank with these specifications to power a 2500

watt pump for 30 minutes daily in the real world.

He will not provide complete specifications for his magic battery. Nor can

he find a manufactured battery that even comes close to his specification.

When a battery was suggested that seems pretty close to *HIS*

specifications, he ridiculed it as being inadequate.

T105

Maximum allowable depth of discharge = 70%

Round Trip efficiency = 85%

Capacity at 100 hr rate = 240Ah

I guess maybe he thinks the 85% efficiency round-trip efficiency vs. his

90% efficiency will somehow make this battery a LOT worse than his

specification.

Maybe he thinks that the T105 has a HIGHER capacity than what he quoted is

also a cause for alarm.

But the fact remains that he continues to claim that HIS battery

specifications are adequate, and that those of the T105 are inadequate.

George would only use T105's in a golf cart. But he cannot tell us what

battery he would use in this system that would work and also match his

specifications.

For panels, George's input is equally baffling:

*>C8 Selected module I at 14 volts at NOCT 2.94A*

*>14 volts is the test standard at 25C. 17 volts is what the produces*

*>when not connected to a load. *

He can provide neither the test standard that requires 14 volts, nor a

commercially produced panel that meets these specifications which HE input.

The values also do not match those that the OP provided.

But he somehow expects this panel with these specifications to work in the

proposed system.

Nick Pine had it correct years ago when he wrote about you: "Who would

hire this nitwit?"

--ron

Posted by *bealiba* on July 24, 2008, 5:14 am

*> On Wed, 23 Jul 2008 16:43:15 -0700 (PDT), beal...@gmail.com wrote:*

*> >The correct minimum battery capacity is 180Ahs. IF you feel that this*

*> >is not correct you can try to prove it wrong.*

*> You wouldn't understand the proof. Your ignoring previous postings as well*

*> as your ongoing piffle is evidence enough of that.*

Which is to say Tweedledee can't prove that the minimum battery

capacity of 180Ahs is wrong. Nothing new there.

*> Again George demonstrates his lack of knowledge of battery chemistry, and*

*> cannot even quote what he wrote correctly!*

*> What George wrote in his specifications:*

*> > B2 Maximum allowable depth of discharge = 70%*

*> > B13 Capacity of battery bank at 100 hr rate (B12 x B10) = 180*

*> > C4 Battery efficiency = 90%*

Almost all deep cycle batteries will stand up to a 80% Maximum Depth

of Discharge. You really do need to learn the difference between

"Maximum DOD" and "Daily DOD". A world of difference between the two.

The 180Ah is the minimum capacity required to do the job.

And the Battery Efficiency, Surprise, surprise it works.

*> And George expects a battery bank with these specifications to power a 2500*

*> watt pump for 30 minutes daily in the real world.*

George never specified a battery. You specified T105s.

*> He will not provide complete specifications for his magic battery. Nor can*

*> he find a manufactured battery that even comes close to his specification.*

George never specified a battery. You specified T105s.

*> When a battery was suggested that seems pretty close to *HIS**

*> specifications, he ridiculed it as being inadequate.*

*> T105*

*> Maximum allowable depth of discharge = 70%*

*> Round Trip efficiency = 85%*

*> Capacity at 100 hr rate = 240Ah*

*> I guess maybe he thinks the 85% efficiency round-trip efficiency vs. his*

*> 90% efficiency will somehow make this battery a LOT worse than his*

*> specification.*

Crap battery. Barely up to the job of running a golf cart. Certainly

worthless for a rate of C0.5

*> Maybe he thinks that the T105 has a HIGHER capacity than what he quoted is*

*> also a cause for alarm.*

Not likely.

*> But the fact remains that he continues to claim that HIS battery*

*> specifications are adequate, and that those of the T105 are inadequate.*

*> George would only use T105's in a golf cart. But he cannot tell us what*

*> battery he would use in this system that would work and also match his*

*> specifications.*

George never specified a battery. You specified T105s.

*> For panels, George's input is equally baffling:*

*> >C8 Selected module I at 14 volts at NOCT 2.94A*

*> >14 volts is the test standard at 25C. 17 volts is what the produces*

*> >when not connected to a load.*

George never specified a panels.

*> He can provide neither the test standard that requires 14 volts, nor a*

*> commercially produced panel that meets these specifications which HE input.*

*> The values also do not match those that the OP provided.*

George never specified a panels.

*> But he somehow expects this panel with these specifications to work in the*

*> proposed system.*

George never specified a panels.

*> Nick Pine had it correct years ago when he wrote about you: "Who would*

*> hire this nitwit?"*

*> --ron*

Nick Pine, mmm, The man with the solar garage. Still laughing over

that one.

> On Mon, 21 Jul 2008 19:36:54 -0700 (PDT), beal...@gmail.com wrote:> >Again. The 180Ah is the minimum battery capacity required. NOT a> >battery recommendation.> >The formula requires the user to input data for chosen equipment. YOU> >chose T105s for the battery but were unable to supply the rest of the> >required information.> No, I asked you if the T105, which has more than a 180Ah capacity at 100> hrs, would work in your system. As usual, you waffled.