[RE-wrenches] Generator/SQFlex problem

[Phil Undercuffler]

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.

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?

Phil
-----------
"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.  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.

There must surely come a time when heat and power will be stored in
unlimited quantities in every community, all gathered by natural forces."
-- Thomas Edison --



On Tue, Jul 5, 2011 at 4:28 PM, Allan Sindelar <
allan at positiveenergysolar.com> wrote:

> **
> Wrenches,
> 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.
>
> 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.
>
> 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.
>
> 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.
>
> Has anyone solved this problem? Any ideas for a reasonably simple and
> trouble-free approach would be welcome.
> Thank you,
> Allan
>
> --
> *Allan Sindelar*
> *Allan at positiveenergysolar.com* <Allan at positiveenergysolar.com>
> NABCEP Certified Photovoltaic Installer
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> *Positive Energy, Inc.*
> 3201 Calle Marie
> Santa Fe, New Mexico 87507
> *505 424-1112*
> *www.positiveenergysolar.com* <http://www.positiveenergysolar.com/>****
>
> *****************
> *
>
>
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