Deep water... [RE-wrenches]

[allan]

Travis,
    For domestic water usage requirements on deep wells I am finding it hard
to beat a SunRise running off a 24V home battery system with a converter
(not array-direct controller), or a 48V home system with a float
switch-activated relay, no converter, and 80% output.  It becomes just
another DC load on the home system, one that is greatest in the summer when
there's an excess of PV capacity.  The 48V or 60V voltage to the pump can be
run a pretty long distance on #6-#10 AWG wire, so it's pretty versatile.
Down to about 300-350' we use the "hand method" of installation, with SDR9
poly pipe; below that it's pretty heavy to lift by hand.  They haven't been
fully trouble-free (in fact, we've probably seen most of the possible
problems, along with Bob-O, I hear), but basic installation and service is
within the capabilities of a good wrench, and Dankoff has provided me with
good support.
    Re the NEC: for us, so far no problems.  Heinemann 125VDC breaker in a
powercenter or Trace box to the converter; output is a load circuit with no
further need for overcurrent protection; use standard wiring techniques.
    Beats the hell out of transformers, big inverters, dual inverters, and
generators.  Does require a storage tank and pressure pump, though.
    I'm biased, though, and should lay that out.  Dankoff and I have some
conflicts of interest--I bought his retail biz 3-4 yrs ago--so I'm not
completely objective.  Still, they have been as good a distributor and
manufacturer as any I have found, and lots better than some.
Allan @ Positive Energy
-----Original Message-----
From: Travis Creswell, Ozark Solar <ozsolar at ipa.net>
To: RE-wrenches at topica.com <RE-wrenches at topica.com>
Date: Wednesday, July 05, 2000 7:38 PM
Subject: Re: Deep water... [RE-wrenches]


>
>----------
>>From: "Steve Willey, Backwoods Solar" <steve at backwoodssolar.com>
>>To: RE-wrenches at topica.com
>>Subject: Re: Deep water... [RE-wrenches]
>>Date: Tue, Jul 4, 2000, 7:09 PM
>>
>
>>They run on 60 or more volts
>>array direct and have inverter and AC motor within the sub-pump as I
recall.
>>But big $$
>
>
>
>I think Steve is pretty much on to something here.  For this application,
>this depth and daily volume solar direct water pumping can't even be
>anywhere close to cost effective.  As others have already suggested the
>volume does sound pretty high.  Given your customers lack of budget I don't
>see solar direct as an option.  They are probably better spending their
>money on the biggest cistern they afford on top of the hill and filling it
>every few days.  If it was just a water pumping application it might be a
>little closer to being cost effective.  Since we are talking about a entire
>house system the only additional cost is the extra inverter to get 240 plus
>a very small amount of additional propane per year.
>
>This would be a good time for some hardcore solar water pumping people to
>help me with the numbers.
>I'd like to see the math come anywhere near a dual inverter system not to
>mention the added complexity of a 180 volt DC water pumping system whose
>only purpose is for pumping water which means there is another array for
>charging batteries. By the way NEC has some real problems with DC voltages
>over 48 in residences.  A dual inverter system would really be the way to
>go. Forget the the T240's.
>
>Don't get me (too) wrong I am running a 1/8 page solar water pumping add in
>my local Big Nickel for 13 weeks as we speak but I just don't like to do
>solar direct systems in houses with inverters.  It might be because most of
>our wells around here are well over 200' feet.
>
>How many of us wrenches are licensed to set and service well pumps?  Try to
>get a well service guy out to service a DC pump.  It "ain't gonna" happen
>here in the Ozarks.
>
>Travis Creswell
>
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