A few more gallons? [RE-wrenches]

matthew tritt solarone at charter.net
Wed Apr 2 19:52:49 PST 2003


Gary,

Are you running the pump at 12 or 24 volts? One thing that'll happen if you
run on battery is that the flow will diminish (compared to solar-direct)
because the max voltage level will be limited by the batteries. How about
dropping another shurflo down the hole to increase your daily output?

You can't use the pump controller if you're running off battery power.

Good luck.

Matt T
----- Original Message -----
From: "Gary Higbee" <gary at windstreamsolar.com>
To: <RE-wrenches at topica.com>
Sent: Wednesday, April 02, 2003 5:24 PM
Subject: A few more gallons? [RE-wrenches]


> Wrenches,
>
> I installed a basic (SHURflo) submersible pump system for a client a while
> back. The system fit their budget and has worked fine. Their garden and
new
> orchard is expanding, though, and we'd like to squeeze more water from the
> system. I'm considering options for an economical solution.
>
> Here's the current configuration: SHURflo 9300 submersible pump and
> controller with low-water sensors, 2x75 watts PV modules, pump placement
at
> 80 feet. Static level around 20 feet much of the year, dropping somewhat
as
> summer progresses. Well tested at 7gpm. We've got plenty of storage, just
> not as much water out of the hole as we'll want in the summer.
>
> I need to go up the mountain and stick my clamp meter on the pump wire,
but
> believe that in peak sun the pump is using reasonably less than the PV
array
> could provide. We may only be using around 1/2-2/3 of the peak PV
potential,
> since the static water level is fairly high until late summer (we've got a
> nominal 150 watts and are likely using around 70). The idea here would be
to
> use a battery supplement to transfer the peak sun PV excess into later-day
> pumping--essentially broadening out the pumping curve.
>
> I'm contemplating adding deep-cycle batteries, a small charge controller,
> and a low-voltage disconnect. It seems that in principle this idea should
> work, though I know the system suddenly becomes more complex. It seems,
too,
> that the controller LCB wouldn't be doing anything, since the battery
would
> be the current source.
>
> In this scheme I think the system would start pumping later in the day,
> since we'd first be charging the battery. Then it should run at a fairly
> uniform rate until the low-voltage cutoff turned things off. Since there
> would be a lot of cycling in this I'd think we'd want to keep a relatively
> high battery voltage. To reduce annual cycling I'd also probably set up
> something to switch to normal PV-driven pumping in the many months when we
> don't have the demand (taking care to float the batteries). I could also
> consider adding a bit more PV.
>
> Would this be worth it?
>
> Any thoughts, suggestions, other ideas?
>
>
> THANKS!
>
> Gary
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>              Gary Higbee  (gary at windstreamsolar.com)
>                      (541 )607-1818 (Eugene)
>                         (541) 954-3881 (Cell)
> Solar, wind, and hydro site analysis and system design
>     Components dealer and installation assistance
>                       ~WindStream Solar~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
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