Hybrid Car – More Fun with Less Gas

How many panels ? ( to run 230 volt sprinkler pump 30 minutes a day?) - Page 4

register ::  Login Password  :: Lost Password?
Posted by Ron Rosenfeld on July 8, 2008, 3:41 am
 
On Sun, 6 Jul 2008 23:37:26 -0700 (PDT), bealiba@gmail.com wrote:


You are the only one who is making those entries.  I don't use that
spreadsheet, and I surely would not have you make data entry for me.

Just to refresh your memory, here is the math:

---------------------
AC Load        2500W x 0.5hrs/day --> 1250 watt-hrs/day
Inverter Efficiency    85%
Adjusted AC Load    1471 Watt-hrs/day

Nominal system voltage    12V  (This is appropriate for your panels)
Total load in AH    123 amp-hrs per day
System Losses, etc      20%

Total Required        147 amp-hrs per day

Worst month insolation     5.08 kWh/m^2 per day (effective full sun hours)

Required array current    28.95A (total/insolation)

Numbe of panels        28.95/2.94 --> 9.85 --> 10 panels
-----------------------------------

Nothing in there about batteries.

Nothing in there about using your spreadsheet or any of your calculations.

--ron

Posted by bealiba on July 9, 2008, 5:27 am
 

Ok, let's look at a system to run 2500Watts of pump for 30 Minutes.

Tweedledee has proposed a system without batteries.

This is the proposal;

---------------------
AC Load         2500W x 0.5hrs/day --> 1250 watt-hrs/day
Inverter Efficiency     85%
Adjusted AC Load        1471 Watt-hrs/day

Nominal system voltage  12V  (This is appropriate for your panels)
Total load in AH        123 amp-hrs per day
System Losses, etc       20%

Total Required          147 amp-hrs per day

Worst month insolation   5.08 kWh/m^2 per day (effective full sun
hours)

Required array current  28.95A (total/insolation)

Numbe of panels         28.95/2.94 --> 9.85 --> 10 panels
-----------------------------------

Simple enough, but then Tweedledee is pretty simple.

First is 1250 Watt hours a day @ 230 Volts AC {This is actually
2941.18 Watts that the inverter is drawing}

The inverter is 85% efficient so we adjust the Whs to 1471Whs {2941.14
Watts}

Nominal system voltage  12V {keep this in mind}

Total load in AH        123 amp-hrs per day {245.1 Amps}

System Losses, etc       20%

Total Required          147 amp-hrs per day {At 12V = 294.12 Amps}

Worst month insolation   5.08 kWh/m^2 per day (effective full sun
hours)

Required array current  28.95A (total/insolation) {Will produce 147.07
Ahs at 12 Volts over 5.08 hours the pump is required to run for half
an hour}

Numbe of panels         28.95/2.94 --> 9.85 --> 10 panels

BUT, the pump requires 2500 Watts to run (2500 Watts / 12V = 208.33
Amps) and something like five times that to start (1041.65 Amps)and
this doesn't even take into account the inverters efficiency.

No matter how you slice it 28.95 amps at 12 volts ain't gonna run that
pump.

Without batteries, Tweedledee's proposal is pure nonsense.

Now Tweedledee will say that of course there are batteries.

BUT, if there are batteries they must be part of the calculation.

Tweedledee is up to his ass in shit and sinking fast.

Posted by Ron Rosenfeld on July 10, 2008, 1:18 am
 On Tue, 8 Jul 2008 22:27:08 -0700 (PDT), bealiba@gmail.com wrote:


I see you are blathering again, George.

You clearly are not interested in having any kind of serious conversation.
You are more interested in parsing out bits and pieces of what has been
written so you can engage in some uncreative name-calling.

You obviously didn't understand why I asked the OP about methods and the
need for energy storage, as compared with your recommendation of a 154
panel system.
--ron

Posted by bealiba on July 10, 2008, 1:58 am
 
As you wished, no batteries, no spreadsheet. Using your calculations.

So predictable. Tell us how 29 Amps of panels at 12 Volts is going to
run a pump that requires 2500 Watts at 230 Volts without batteries.
Because that's what you said. You can't get much more serious than
that.

Perhaps you now want to add the batteries to the equation now.


Posted by wmbjkREMOVE on July 8, 2008, 12:39 am
 On Sun, 06 Jul 2008 22:44:54 -0400, Ron Rosenfeld



Some save time by substituting rules of thumb for manufacturers'
specs. This makes sense on Planet Ghio because somebody with a few
years of experience with a propane tank and a 1kWh per day solar setup
is obviously sure to know more than companies that build batteries...
or anybody for that matter. In fact, our very own power consultant
ghinius' brain has so many RoTs crammed into it that there simply
isn't any room left for learning anything useful, er... new. It's
apparently a case of stagnation due to knowing too much!  <snorf>

Wayne

This Thread
Bookmark this thread:
 
 
 
 
 
 
  •  
  • Subject
  • Author
  • Date
please rate this thread