Deep Well (400'-600' TDH) Water Pumping [RE-wrenches]

Sat Aug 25 07:36:20 PDT 2001

I wish to amend my original quote of 100% trouble rate with DC pumps to a
more accurate 75%.  Also please note I am talking about all DC pumps not
just submersibles.  It still feels like 100% though and the only other
product that comes even close to costing me as much money, time and
reputation was a bad batch of over 300 Leviton Occupancy Sensors we
installed at two La-Z-Boy factories.  Also, 2 of those DC pumps include
those made by a small manufacturer from New Mexico whose name starts with D
and have been sold in the last 2 years.  So, I'm not going for "they're
better today than they used to be".  Even though I truly believe they are
better I am from the "Show-Me" state!  One was a controller problem but that
still counts in my book.

Please don't get me wrong, as I am not trying to beat up on DC pumps.  They
HAVE already succeeded in beating me up.  There is no arguing that if you
need more than a few hundred gallons a day and don't need any AC then a DC
pump is the way to go.  Low head irrigation and stock tanks fed by  wells
under 200' (still can be pulled by hand) are perfect applications and I will
continue to actively promote those applications even knowing that odds are
heavily stacked against me.  I would be even more likely to promote DC
pumping if certain pump manufacturers/distributors didn't sign up new
dealers in my back yard who have never even seen a solar panel.

In this particular situation (too deep and the customer needs AC) that I'm
designing for I have pretty much ruled them out unless someone could show me
some radical savings compared to a dual inverter system.  Windy,  you are
more the welcome to put the numbers together and if you'll pay my labor to
repair and trouble shoot it the first year I'd love to put it in.  As I
don't expect that to happen, I'll be selling the customer a dual inverter
system that has never given me ANY trouble and let the well service company
sell him the pump that they know will last for 20 yrs and cost less than
$300.  The customer can enjoy all the power and water he needs and I can
enjoy not eating a bunch of labor when I could be out making money or even
better, home on a Saturday with my family.  It boils down to a personal
(lost time with family) and financial decision to choose a product that has
been reliable for over 30 years (not less than 2 years) or go with a new
product that has proven to be very unreliable and very expensive with no
recourse to reclaim money lost from servicing it when it fails.

Travis Creswell
Ozark Solar

----- Original Message -----
From: "Windy Dankoff, Dankoff Solar" <windy at dankoffsolar.com>
To: <RE-wrenches at topica.com>
Sent: Friday, August 24, 2001 8:19 PM
Subject: Re: Deep Well (400'-600' TDH) Water Pumping [RE-wrenches]

> >I don't see what all the fuss is about on DC pumps. I have sold and
installed
> >at least a dozen or so in the past 2 years, and have had next to no
problems
> >with them. Most of the problems I experienced were with bum pump
controllers,
> >and those were minimal. Windy, please jump in here.......
> >
> >SUNcerely,
> >Frank Fowler
>
> OK, OK ... Thanks for inviting me, Frank. I didn't want to jump in
> right away with what might be seen as a promotional rap, but thanks
> guys for helping to balance the conversation.
>
> There are two things to realize about DC pumps:
>
> 1. They represent a 100% re-invention of the well pump beginning only
> 15 years ago, as opposed to the 50-year history of AC submersibles.
> Our SunRise pump is the finest of the lot (for home-size pumps).
> We've seen our problems, but there have been about a dozen
> incremental improvements made just in the last 4 years. That's why
> dealers like Frank report satisfying results in the past 2 years.
>
> 2. The low-power DC pumps that are competitive for home systems are
> positive displacement pumps, as opposed to centrifugal/impeller AC
> pumps. They have more moving parts due to the reciprocating
> mechanisms that are used. They also pump more slowly (using low power
> / that's what makes them so special) but that means they run more
> hours per day. We and our customers must accept that these factors
> add up to more frequent maintenance. However, we are well past the
> stage where premature failures are significant. We can now reasonably
> expect maintenance intervals in the 5-10 year range with SunRise
> sealed-piston pumps (2-5 years with cheaper diaphragm pumps). The
> more frequent maintenance can be balanced by the fact that the power
> system can be FAR smaller. Not only is a large inverter load
> eliminated, but the daily energy (watt-hour) load is typically well
> under half.
>
> Admittedly, if your customer needs or wants a large inverter for
> other uses, and needs only a SMALL daily volume of water then an AC
> pump is a viable choice (watt-hours per day is not so big
> regardless). On the other hand, if the water need is substantial
> (gardening etc.) and there is NOT otherwise a need for a multi-KW
> inverter, then the DC pump can save $thousands of initial cost. In
> that case, a bit more maintenance is an acceptable trade-off. As
> Steve Willey just said "Don't rule them out for the smaller simpler
> systems where a larger inverter would not otherwise be needed."
>
> So ... Some swear by 'em and some swear at 'em ... but in
> consideration of #1 above, please realize that a lot of the
> swearing-at is in reaction to early products that have undergone
> considerable improvement in just the past couple of years.
>
> Patiently DC since '83,
>
> Windy Dankoff
> --
>
> Windy Dankoff
>     Founder
>     Vice President, Technical Development & Training
>     Direct e-mail: windy at dankoffsolar.com
>
> Dankoff Solar Products, Inc.
>     Wholesale distributor of solar equipment
>     Manufacturer & importer of solar water pumps
>
> 2810 Industrial Rd.
> Santa Fe, NM  87505  USA
> (505) 473-3800    FAX  (505) 473-3830
> E-mail:   info at dankoffsolar.com
>
> SEE OUR INFORMATIVE WEB SITE AT:
> http://www.dankoffsolar.com
>
> ===  EN ESPANOL:  ===
> http://www.dankoffsolar.com/index.htmls
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