Posted by *bealiba* on July 14, 2008, 12:57 am

*> On Sun, 6 Jul 2008 19:07:12 -0700 (PDT), beal...@gmail.com wrote:*

*> >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 =15c*

*> >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%*

*> >C1 Design tilt*

*> >C2 Design month*

*> >C3 Total energy demand per day (A8) =122.55Ah*

*> >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*

*> >Prove it wrong.*

*> Let's get back to this challenge of yours, as to whether your*

*> specifications will run the OP's 2500watt pump 1/2 hour per day, every day.*

*> You give incomplete specifications, so it's a tough to run a simulation.*

*> But perhaps, if you can fill in a few details, or agree with some of my*

*> assumptions, we can proceed with a simulation:*

You have the formula, put in your chosen parameters.

*> With regard to your selected module:*

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

If you like, It's closer to the truth than anything you have said

*> Does this mean it has an STC nameplate power rating of 14*2.94 = 41.16*

*> watts? Or is the STC nameplate power rating something else?*

When was the last time you ever saw a panel of (Enter Number Here)

rated watts produce that rating outside of lab conditions. You name a

temperature and we can use it.

*> >C13 Number of parallel strings of modules (C5 / C12) = 10.3*

*> I will round this up to 11.*

*> Do you want to consider the effect of temperature on the module?*

You name a temperature and we can use it.

*> If you do, then we need to use some assumptions about the temperature*

*> coefficient, NOCT and MPPT efficiency at std. test conditions.*

Ah. you want to guess.

*> I would assume*

*> Temperature coefficient of power = -0.5%/C*

*> NOCT 45.2C*

*> MPPT Efficiency at std test cond 13%*

This is your best guess is it? From the standard test temp of 25C my

checking shows that at 45C:

1) there is an increase of around 1%in the short circuit current

2) A decrease of around 8.5% in the open circuit voltage

3) A decrease of around 6% in the maximum power.

*> but we can use different values if you like, or ignore temperature affects*

*> completely.*

*> With regard to the battery, you have supplied this information:*

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

*> >B13 Capacity of battery bank at 100 hr rate (B12 x B10) = 225*

*> >C4 Battery efficiency = 90%*

Ah, no. That was your battery recommendation. If you will remember the

180 Ah was the minimum capacity required. Battery specs to be supplied

by user. You said T105s at 225Ah. Feel free to change this if you

like.

*> The real world battery I could find (in my database) closest to these*

*> specifications:*

Is this the database that contains T105s and L16s as the worlds supply

of batteries.

*> Trojan T105*

*> Maximum allowable depth of discharge = 70%*

*> Capacity at 100 hr rate = 240*

*> Efficiency 85%*

*> So I would use two of these in series to provide a 12V battery bank.*

*> Let me know.*

You have the formula, go for it

*> --ron*

Posted by *Ron Rosenfeld* on July 14, 2008, 8:46 pm

On Sun, 13 Jul 2008 17:57:39 -0700 (PDT), bealiba@gmail.com wrote:

*>> On Sun, 6 Jul 2008 19:07:12 -0700 (PDT), beal...@gmail.com wrote:*

*>> >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%*

*>>*

*>> >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*

*>>*

*>> >Prove it wrong.*

*>>*

*>> Let's get back to this challenge of yours, as to whether your*

*>> specifications will run the OP's 2500watt pump 1/2 hour per day, every day.*

*>>*

*>> You give incomplete specifications, so it's a tough to run a simulation.*

*>> But perhaps, if you can fill in a few details, or agree with some of my*

*>> assumptions, we can proceed with a simulation:*

*>You have the formula, put in your chosen parameters.*

*>>*

*>> With regard to your selected module:*

*>>*

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

*>If you like, It's closer to the truth than anything you have said*

*>>*

*>> Does this mean it has an STC nameplate power rating of 14*2.94 = 41.16*

*>> watts? Or is the STC nameplate power rating something else?*

*>When was the last time you ever saw a panel of (Enter Number Here)*

*>rated watts produce that rating outside of lab conditions. You name a*

*>temperature and we can use it.*

*>>*

*>> >C13 Number of parallel strings of modules (C5 / C12) = 10.3*

*>>*

*>> I will round this up to 11.*

*>>*

*>> Do you want to consider the effect of temperature on the module?*

*>You name a temperature and we can use it.*

*>>*

*>> If you do, then we need to use some assumptions about the temperature*

*>> coefficient, NOCT and MPPT efficiency at std. test conditions.*

*>Ah. you want to guess.*

*>>*

*>> I would assume*

*>> Temperature coefficient of power = -0.5%/°C*

*>> NOCT 45.2°C*

*>> MPPT Efficiency at std test cond 13%*

*>This is your best guess is it? From the standard test temp of 25C my*

*>checking shows that at 45C:*

*>1) there is an increase of around 1%in the short circuit current*

*>2) A decrease of around 8.5% in the open circuit voltage*

*>3) A decrease of around 6% in the maximum power.*

*>>*

*>> but we can use different values if you like, or ignore temperature affects*

*>> completely.*

*>>*

*>> With regard to the battery, you have supplied this information:*

*>>*

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

*>> >B13 Capacity of battery bank at 100 hr rate (B12 x B10) = 225*

*>> >C4 Battery efficiency = 90%*

*>Ah, no. That was your battery recommendation. If you will remember the*

*>180 Ah was the minimum capacity required. Battery specs to be supplied*

*>by user. You said T105s at 225Ah. Feel free to change this if you*

*>like.*

*>>*

*>> The real world battery I could find (in my database) closest to these*

*>> specifications:*

*>Is this the database that contains T105s and L16s as the worlds supply*

*>of batteries.*

*>>*

*>> Trojan T105*

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

*>> Capacity at 100 hr rate = 240*

*>> Efficiency 85%*

*>>*

*>> So I would use two of these in series to provide a 12V battery bank.*

*>>*

*>> Let me know.*

*>You have the formula, go for it*

*>>*

*>> --ron*

Well, I gave you a serious opportunity to supply some clarification to your

incomplete specifications, so as to run a real-world simulation, and you

clearly are unable to do that.

I'd call that pretty sad for someone who purports to be a solar power

consultant.

--ron

Posted by *Ron Rosenfeld* on July 15, 2008, 1:56 pm

On Sun, 13 Jul 2008 17:57:39 -0700 (PDT), bealiba@gmail.com wrote:

*>> With regard to your selected module:*

*>>*

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

*>If you like, It's closer to the truth than anything you have said*

*>>*

*>> Does this mean it has an STC nameplate power rating of 14*2.94 = 41.16*

*>> watts? Or is the STC nameplate power rating something else?*

*>When was the last time you ever saw a panel of (Enter Number Here)*

*>rated watts produce that rating outside of lab conditions. You name a*

*>temperature and we can use it.*

*>>*

*>> Do you want to consider the effect of temperature on the module?*

*>You name a temperature and we can use it.*

*>>*

*>> If you do, then we need to use some assumptions about the temperature*

*>> coefficient, NOCT and MPPT efficiency at std. test conditions.*

*>Ah. you want to guess.*

*>>*

*>> I would assume*

*>> Temperature coefficient of power = -0.5%/°C*

*>> NOCT 45.2°C*

*>> MPPT Efficiency at std test cond 13%*

*>This is your best guess is it? From the standard test temp of 25C my*

*>checking shows that at 45C:*

*>1) there is an increase of around 1%in the short circuit current*

*>2) A decrease of around 8.5% in the open circuit voltage*

*>3) A decrease of around 6% in the maximum power.*

This post clearly demonstrates that George doesn't know what NOCT is, even

though he uses it in his useless spreadsheet. He also doesn't know how to

measure or estimate it, nor does he realize the consequences of making

measurements at a test temperature of 25°C vs measurements at a NOCT of

45°C.

--ron

Posted by *bealiba* on July 15, 2008, 11:04 pm

*> On Sun, 13 Jul 2008 17:57:39 -0700 (PDT), beal...@gmail.com wrote:*

*> >> With regard to your selected module:*

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

*> >If you like, It's closer to the truth than anything you have said*

*> >> Does this mean it has an STC nameplate power rating of 14*2.94 = 41.16*

*> >> watts? Or is the STC nameplate power rating something else?*

*> >When was the last time you ever saw a panel of (Enter Number Here)*

*> >rated watts produce that rating outside of lab conditions. You name a*

*> >temperature and we can use it.*

*> >> Do you want to consider the effect of temperature on the module?*

*> >You name a temperature and we can use it.*

*> >> If you do, then we need to use some assumptions about the temperature*

*> >> coefficient, NOCT and MPPT efficiency at std. test conditions.*

*> >Ah. you want to guess.*

*> >> I would assume*

*> >> Temperature coefficient of power = -0.5%/C*

*> >> NOCT 45.2C*

*> >> MPPT Efficiency at std test cond 13%*

*> >This is your best guess is it? From the standard test temp of 25C my*

*> >checking shows that at 45C:*

*> >1) there is an increase of around 1%in the short circuit current*

*> >2) A decrease of around 8.5% in the open circuit voltage*

*> >3) A decrease of around 6% in the maximum power.*

*> This post clearly demonstrates that George doesn't know what NOCT is, even*

*> though he uses it in his useless spreadsheet. He also doesn't know how to*

*> measure or estimate it, nor does he realize the consequences of making*

*> measurements at a test temperature of 25C vs measurements at a NOCT of*

*> 45C.*

*> --ron*

3) NOCT Normal Operating Cell Temperature. This is "C8" and is user

input from the manufacturer's data.

Posted by *Ron Rosenfeld* on July 16, 2008, 1:53 am

On Tue, 15 Jul 2008 16:04:49 -0700 (PDT), bealiba@gmail.com wrote:

*>3) NOCT Normal Operating Cell Temperature. This is "C8" and is user*

*>input from the manufacturer's data.*

Unfortunately, many do not supply it. So what will George do in that case?

--ron

> On Sun, 6 Jul 2008 19:07:12 -0700 (PDT), beal...@gmail.com wrote:> >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 =15c> >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%> >C1 Design tilt> >C2 Design month> >C3 Total energy demand per day (A8) =122.55Ah> >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> >Prove it wrong.> Let's get back to this challenge of yours, as to whether your> specifications will run the OP's 2500watt pump 1/2 hour per day, every day.> You give incomplete specifications, so it's a tough to run a simulation.> But perhaps, if you can fill in a few details, or agree with some of my> assumptions, we can proceed with a simulation: