Posted by *bealiba* on July 15, 2008, 11:12 pm

*> On Tue, 15 Jul 2008 05:51:06 -0700 (PDT), beal...@gmail.com wrote:*

*> >> On Sun, 13 Jul 2008 16:02:23 -0700 (PDT), beal...@gmail.com wrote:*

*> >> >> On Sat, 12 Jul 2008 17:21:56 -0700 (PDT), beal...@gmail.com wrote:*

*> >> >> >> GG: 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. Surprised you don't know this.*

*> >> >> No, I was not aware of a test standard that specified a particular*

*
voltage*
*> >> >> for the PV cell.*

*> >> >> What standard is that?*

*> >> >> The standards I've seen with regard to PV panels are STC and PTC.*

*> >> >> But they both refer to wattage ratings under specified conditions of*

*> >> >> irradiance, temperature and, for the PTC standard, wind speed. Neither*

*
one*
*> >> >> mentions a particular voltage.*

*> >> >> NOCT is not mentioned in either of those standards, and the irradiance*

*
used*
*> >> >> to determine NOCT is not the same as that used in either STC or PTC*

*> >> >> standards.*

*> >> >> --ron*

*> >> >Sad.*

*> >> Yes it is sad that you obviously have no idea of the meaning of STC, PTC or*

*> >> NOCT.*

*> >> --ron*

*> >Time to look at Tweedledee's claims about;*

*> >1) STC - DC watts-The nameplate rating of a solar module.*

*> >2) PTC - DC watts-the rating of a module in real-world conditions as*

*> >determined by the California Energy Commission.*

*> >PTC it seems is not used anywhere other than California to determine*

*> >the rebate paid for solar power installations.*

*> >Tweedledee left this part of the information out - CEC AC watts - the*

*> >total PTC DC of solar modules factoring in inverter efficiency. This*

*> >the number that the rebate is based on. This rebate is generally for*

*> >"Grid Connect" systems. Not stand alone systems.*

*> >But,*

*> >Notice where it says "the total PTC DC of solar modules factoring in*

*> >inverter efficiency." it looks suspiciously like "A5 & C10" in the*

*> >formula, and "STC DC watts-The nameplate rating of a solar module"*

*> >bears a striking resemblance to "C8"*

*> >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*

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

*> >input from the manufacturer's data.*

*> > Oops, Tweedledee has his foot in his mouth again.*

*> Substitute GG for Tweedledee and you've got the right foot in the right*

*> mouth!*

*> GG still has failed to produce any real world items for use, and the*

*> specifications he provides us with continue to need clarification which he*

*> is unable to supply.*

*> He has yet to justify the 14 Volt specification in C8.*

User input required at C8

*> He's now bringing in PTC. I'm waiting for him to start talking about the*

*> GTC (Ghinius Test Conditions -- a proprietary and secret method of rating*

*> panels, which no manufacturer uses, but should, if they expect GG to*

*> recommend their products).*

*> --ron*

You brought up PTC in hopes of muddying the water a bit more in your

quest to sound knowledgeable.

Posted by *Ron Rosenfeld* on July 14, 2008, 8:48 pm

On Sun, 13 Jul 2008 16:02:23 -0700 (PDT), bealiba@gmail.com wrote:

*>> On Sat, 12 Jul 2008 17:21:56 -0700 (PDT), beal...@gmail.com wrote:*

*>> >> GG: 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. Surprised you don't know this.*

*>>*

*>> No, I was not aware of a test standard that specified a particular voltage*

*>> for the PV cell.*

*>>*

*>> What standard is that?*

*>>*

*>> The standards I've seen with regard to PV panels are STC and PTC.*

*>>*

*>> But they both refer to wattage ratings under specified conditions of*

*>> irradiance, temperature and, for the PTC standard, wind speed. Neither one*

*>> mentions a particular voltage.*

*>>*

*>> NOCT is not mentioned in either of those standards, and the irradiance used*

*>> to determine NOCT is not the same as that used in either STC or PTC*

*>> standards.*

*>> --ron*

*>Sad.*

It is truly sad that reality does not match George's fantasy.

--ron

Posted by *bealiba* on July 15, 2008, 7:46 am

*> On Sun, 13 Jul 2008 16:02:23 -0700 (PDT), beal...@gmail.com wrote:*

*> >> On Sat, 12 Jul 2008 17:21:56 -0700 (PDT), beal...@gmail.com wrote:*

*> >> >> GG: 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. Surprised you don't know this.*

*> >> No, I was not aware of a test standard that specified a particular voltage*

*> >> for the PV cell.*

*> >> What standard is that?*

*> >> The standards I've seen with regard to PV panels are STC and PTC.*

*> >> But they both refer to wattage ratings under specified conditions of*

*> >> irradiance, temperature and, for the PTC standard, wind speed. Neither one*

*> >> mentions a particular voltage.*

*> >> NOCT is not mentioned in either of those standards, and the irradiance used*

*> >> to determine NOCT is not the same as that used in either STC or PTC*

*> >> standards.*

*> >> --ron*

*> >Sad.*

*> It is truly sad that reality does not match George's fantasy.*

*> --ron*

We're still waiting on your all inclusive spread sheet that allows for

all the solar equipment in the world and complete pricing for same.

We are also waiting for yor caluclation for the numbers you proposed

for this post;

From Tweedledee -

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:

With regard to your selected module:

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

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?

*>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?

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

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

I would assume

Temperature coefficient of power = -0.5%/C

NOCT 45.2C

MPPT Efficiency at std test cond 13%

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%*

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

specifications:

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.

Well, come on you have the formula, these are the numbers you feel

should be used, show us the calculation.

Posted by *Ron Rosenfeld* on July 15, 2008, 8:02 pm

On Tue, 15 Jul 2008 00:46:05 -0700 (PDT), bealiba@gmail.com wrote:

*>> On Sun, 13 Jul 2008 16:02:23 -0700 (PDT), beal...@gmail.com wrote:*

*>> >> On Sat, 12 Jul 2008 17:21:56 -0700 (PDT), beal...@gmail.com wrote:*

*>> >> >> GG: 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. Surprised you don't know this.*

*>>*

*>> >> No, I was not aware of a test standard that specified a particular voltage*

*>> >> for the PV cell.*

*>>*

*>> >> What standard is that?*

*>>*

*>> >> The standards I've seen with regard to PV panels are STC and PTC.*

*>>*

*>> >> But they both refer to wattage ratings under specified conditions of*

*>> >> irradiance, temperature and, for the PTC standard, wind speed. Neither one*

*>> >> mentions a particular voltage.*

*>>*

*>> >> NOCT is not mentioned in either of those standards, and the irradiance used*

*>> >> to determine NOCT is not the same as that used in either STC or PTC*

*>> >> standards.*

*>> >> --ron*

*>>*

*>> >Sad.*

*>>*

*>> It is truly sad that reality does not match George's fantasy.*

*>> --ron*

*>We're still waiting on your all inclusive spread sheet that allows for*

*>all the solar equipment in the world and complete pricing for same.*

I'm sure *YOU* would require something like that, so you can blame any of

your misguided recommendations on whoever devised the database. But a real

solar power consultant would not.

*>We are also waiting for yor caluclation for the numbers you proposed*

*>for this post;*

And I'm waiting to see if you agree with any of them. Clearly, you cannot

recommend an efficient real-world system.

*>From Tweedledee -*

*>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:*

*>With regard to your selected module:*

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

*>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?*

*>>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?*

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

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

*>I would assume*

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

*> NOCT 45.2°C*

*> MPPT Efficiency at std test cond 13%*

*>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%*

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

*>specifications:*

*>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.*

*>Well, come on you have the formula, these are the numbers you feel*

*>should be used, show us the calculation.*

I was trying to help you formulate a real world system to run through the

simulation. Clearly, that is beyond your ability. Sad. Especially for

one who claims to be knowledgeable in this field.

In another post, GG writes about me: "He has learned more about solar

in the last two weeks than he ever learned in the last 10 years."

What I've learned in the last two weeks is that GG is even less competent,

and less able to learn, than I had originally concluded. That shouldn't be

a surprise, I know. But I did have hopes.

He can't specify either a real world panel or a real world battery for his

Kilauea water pump system. He can only come up with unrealistic

specifications, and, when real world specifications are proposed to him, he

can neither accept them, nor propose different ones.

And then, to compound his errors, he writes:

*>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.*

*>>*

If his 45C is an ambient temperature, he's someplace far from Kilauea, HI

where the highest annual temp is around 33C, and the average annual temp is

about 29C.

If he's trying to compare what happens at STC (which is at 25C), when we

change the conditions so that the operating cell temperature (OCT) is the

NOCT, then he doesn't know what NOCT is or how to calculate it.

Hint for GG: The OCT at STC will be higher than the NOCT.

--ron

Posted by *Solar Flare* on July 15, 2008, 9:20 pm

He seems smart enough to invoke many responses from the so-called

"brainchilds" here. Where does that put you?

Maybe a little maturity would help you out?

*> I was trying to help you formulate a real world system to run through the*

*> simulation. Clearly, that is beyond your ability. Sad. Especially for*

*> one who claims to be knowledgeable in this field.*

*> In another post, GG writes about me: "He has learned more about solar*

*> in the last two weeks than he ever learned in the last 10 years."*

*> What I've learned in the last two weeks is that GG is even less competent,*

*> and less able to learn, than I had originally concluded. That shouldn't *

*> be*

*> a surprise, I know. But I did have hopes.*

*> He can't specify either a real world panel or a real world battery for his*

*> Kilauea water pump system. He can only come up with unrealistic*

*> specifications, and, when real world specifications are proposed to him, *

*> he*

*> can neither accept them, nor propose different ones.*

*> And then, to compound his errors, he writes:*

*>>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.*

*>>>*

*> If his 45C is an ambient temperature, he's someplace far from Kilauea, HI*

*> where the highest annual temp is around 33C, and the average annual temp *

*> is*

*> about 29C.*

*> If he's trying to compare what happens at STC (which is at 25C), when we*

*> change the conditions so that the operating cell temperature (OCT) is the*

*> NOCT, then he doesn't know what NOCT is or how to calculate it.*

*> Hint for GG: The OCT at STC will be higher than the NOCT.*

*> --ron *

> On Tue, 15 Jul 2008 05:51:06 -0700 (PDT), beal...@gmail.com wrote:> >> On Sun, 13 Jul 2008 16:02:23 -0700 (PDT), beal...@gmail.com wrote:> >> >> On Sat, 12 Jul 2008 17:21:56 -0700 (PDT), beal...@gmail.com wrote:> >> >> >> GG: 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. Surprised you don't know this.> >> >> No, I was not aware of a test standard that specified a particular