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Allan,<br>
<br>
General purpose relays seem to be rated for 30 volts dc.<br>
Here are a couple possibilities for a dc relay that will handle the PV
power:<br>
Panasonic AEP51012 (Mechanical relay - very expensive and difficult to
get)<br>
Crydom D2D12
or D2D40 (Solid state relays)<br>
It looks like the D2D40 will handle the necessary current without a
heat sink.<br>
<br>
Kent Osterberg<br>
Blue Mountain Solar<br>
<br>
<br>
<br>
Allan Sindelar wrote:
<blockquote cite="mid:4E186530.5040302@positiveenergysolar.com"
type="cite">
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Phil and Wrenches,<br>
Thank you for the response; good food for thought. <br>
<br>
We looked at Aerovironment as a result of your suggestion, but it
appears to be out of production and unavailable. <br>
<br>
Kent's suggestion to use the gennie starting battery also makes sense,
as the battery would be recharged daily and the load is negligible. I
also suspect that a Morningstar SunLight controller with a small PV
module would provide the daily start/stop signal to the Relay Driver. <br>
<br>
However, as Kent points out, finding a relay would be difficult, as the
customer is looking at controlling multiple (four?) SQF pumps from AC
or their respective arrays. That's too many poles at too high a DC
voltage to prevent arcing - multiple relays with 240V AC coils
paralleled would handle control of the relays, but can anyone suggest a
relay that can handle 100-150 VDC array voltage? MDI mercury
contactors, as were used in early APT/Pulse powercenters, come to mind,
available in 1-3 poles. Any better ideas?<br>
<br>
While solutions to some of the issues are workable, ultimately I don't
see an easy way to accomplish what he wants to do. He's talking 10-12
gpm continuously 24/7. That's 30gpm raised 400' if array-direct, more
than any solar pumps I know can supply. Thus the diesel generator for
night operation. Ranchers are used to diesel generators.<br>
<br>
<div class="moz-signature">
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<title></title>
<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a moz-do-not-send="true"
href="mailto:Allan@positiveenergysolar.com"><font color="#000099"
face="Times New Roman, Times, serif"><u>Allan@positiveenergysolar.com</u></font></a></small><font
face="Times New Roman, Times, serif"><br>
<span style="font-size: 10pt;">NABCEP Certified Photovoltaic Installer<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
<b>Positive Energy, Inc.</b><br>
3201 Calle Marie<br>
Santa Fe, New Mexico 87507<br>
<b>505 424-1112</b><br>
<a moz-do-not-send="true" href="http://www.positiveenergysolar.com/"
target="_blank"><u>www.positiveenergysolar.com</u></a><o:p></o:p></span></font>
<p class="MsoNormal" style="margin-right: 722.25pt;"><span
style="font-size: 10pt;"><font
face="Times New Roman, Times,
serif"><st1:place w:st="on"><st1:city
w:st="on"></st1:city><st1:state w:st="on"></st1:state><st1:postalcode
w:st="on"></st1:postalcode></st1:place></font><b style=""><br>
</b></span></p>
<span style="font-size: 10pt;"><br>
</span> </div>
<br>
On 7/5/2011 6:57 PM, Phil Undercuffler wrote:
<blockquote
cite="mid:CAPLQxE+_HuF1k1wqxzt0Q5_7FHyC_Kd=5Cs0Dr=aJujbUWgt9g@mail.gmail.com"
type="cite"><font size="2"><font face="arial,helvetica,sans-serif">Use
an ac charger to charge a small battery when the generator runs each
evening, and then power a timer or photosensor from the battery.
Sears, <$40. I wouldn't worry about the phantom load of the timer
-- you're running an 8kW diesel genset throughout the night. It oughta
keep up. <br clear="all">
</font></font>
<div>
<div><font class="Apple-style-span"
face="arial, helvetica,
sans-serif"><br>
</font></div>
<div><font class="Apple-style-span"
face="arial, helvetica,
sans-serif">The question I can't
answer is how this makes sense, with diesel above $4/gallon and service
every 100 hours. Did you look at an Aerovironment UPC controller
running array direct with a standard AC pump? </font></div>
<div><font class="Apple-style-span"
face="arial, helvetica,
sans-serif"><br>
</font></div>
<div>Phil
<div>-----------</div>
<div><span
style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 15px;">"</span><span
style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 15px;">When
we learn how to store electricity, we will cease being apes ourselves;
until then we are tailless orangutans. You see, we should utilize
natural forces and thus get all of our power. Sunshine is a form of
energy, and the winds and the tides are manifestations of energy. </span><span
style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 15px;">Do
we use them? Oh, no! We burn up wood and coal, as renters burn up the
front fence for fuel. We live like squatters, not as if we owned the
property. </span></div>
<div><span
style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 15px;"><br>
</span></div>
<div><span
style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 15px;"></span><span
style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 15px;">There
must surely come a time when heat and power will be stored in unlimited
quantities in every community, all gathered by natural forces."</span></div>
<div><span
style="font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 15px;">--
Thomas Edison --</span></div>
<br>
<br>
<br>
<div class="gmail_quote">On Tue, Jul 5, 2011 at 4:28 PM, Allan
Sindelar <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:allan@positiveenergysolar.com">allan@positiveenergysolar.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000"> Wrenches,<br>
A good client of ours is a rancher in the New Mexico/Arizona border
area. He has a specific need for which I couldn't offer a simple system.<br>
<br>
He needs to raise water from a lake 400+/- vertical feet to a 100K
gallon storage tank for agricultural use. The site is remote. The
amount is substantial - about 10-12 gpm continuously, 24/7. He would
like to use 4 Grundfos SQ Flex pumps at about 2.5-3 gpm, each running
array-direct feeding a common pipe to the tank. He then wants to use
about an 8kW (derated to 6kW for 7,500' elevation) diesel generator
(with standard two-wire automatic start) to run all four pumps when the
sun goes down, and shut off and transfer back to PV when the sun comes
up the next morning.<br>
<br>
How might this be done? If we assume that each pump has four 210W
modules, that would be an 80Vnom array with MPP around 120V and Voc
around 150V. I would assume that both of these voltages are too high to
use any stand-alone AGS, such as Atkinson or Magnum. We considered a
separate tiny 12V or 24V battery with small PV module, used just to
power an AGS voltage sense signal, with the voltage difference between
float (13.6V) and rest (12.7V) triggering a voltage-actuated start
signal, but rejected this as problematic as battery temperatures
affected charge voltages. A self-contained time switch, such as some of
the newer Intermatic units, might work, if the right model can be
identified and isn't a substantial phantom load.<br>
<br>
We would also have to adapt a relay to switch between sources, with a
120 or 240 V AC relay coil current, energized by the generator. The
Grundfos IO101 AC interface unit is manual only.<br>
<br>
Has anyone solved this problem? Any ideas for a reasonably simple and
trouble-free approach would be welcome.<br>
Thank you,<br>
Allan<br>
<br>
<div>-- <br>
<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a moz-do-not-send="true"
href="mailto:Allan@positiveenergysolar.com" target="_blank"><font
color="#000099"
face="Times
New Roman, Times, serif"><u>Allan@positiveenergysolar.com</u></font></a></small><font
face="Times New Roman, Times, serif"><br>
<span style="font-size: 10pt;">NABCEP Certified Photovoltaic
Installer<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
<b>Positive Energy, Inc.</b><br>
3201 Calle Marie<br>
Santa Fe, New Mexico 87507<br>
<b><a moz-do-not-send="true" href="tel:505%20424-1112"
value="+15054241112" target="_blank">505 424-1112</a></b><br>
<a moz-do-not-send="true"
href="http://www.positiveenergysolar.com/" target="_blank"><u>www.positiveenergysolar.com</u></a></span></font>
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style="font-size: 10pt;"><b><br>
</b></span></p>
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