Thoughts on Grundfos running off 12v with step-up converter

I have a 130’ well and I’ll be pumping into a 40 psi pressure tank, so for simplicity sake I’ll call it 220’. Well yields 2-3 gpm.
I’d like to run a DC pump off my 12v battery system (four 125AH AGM 12v in parallel). looking at Grundfos 3SQF-2. Grundfos accepts 30-300VDC with best performance being at or above 120vdc. To boost my 12v I’m looking at a 12 to 48v 4amp converter like this:
http://www.ebay.com/itm/New-DC-Converter-12V-to-48V-4A-192W-Step-Up-Boost-Power-Supply-Module-Car-/221828979379?pt=LH_DefaultDomain_0&hash=item33a6099ab3
Is there something better out there to do this job? I’d like to try and get a flow rate of around 2.5 gpm, and I think this might do that but unfortunately I find the Grundfos info difficult to interpret.
Since I’ll be running off of batteries at a constant voltage/current I’m thinking I can get away with wiring the pump direct without a controller?
I’d appreciate any comments or suggestions from knowledgable folks on this before I put down $$ for it - Thanx!
I’d like to run a DC pump off my 12v battery system (four 125AH AGM 12v in parallel). looking at Grundfos 3SQF-2. Grundfos accepts 30-300VDC with best performance being at or above 120vdc. To boost my 12v I’m looking at a 12 to 48v 4amp converter like this:
http://www.ebay.com/itm/New-DC-Converter-12V-to-48V-4A-192W-Step-Up-Boost-Power-Supply-Module-Car-/221828979379?pt=LH_DefaultDomain_0&hash=item33a6099ab3
Is there something better out there to do this job? I’d like to try and get a flow rate of around 2.5 gpm, and I think this might do that but unfortunately I find the Grundfos info difficult to interpret.
Since I’ll be running off of batteries at a constant voltage/current I’m thinking I can get away with wiring the pump direct without a controller?
I’d appreciate any comments or suggestions from knowledgable folks on this before I put down $$ for it - Thanx!
Comments
Welcome to the forum.
I don't know much about your system or the design criteria that went into it, but four AGM batteries in parallel is a red flag that the design is not optimal. Before you compound your errors by spending more money, perhaps you should give some thought to raising your system voltage to 24 or 48 volts.
You are not the first to paint yourself into a 12 volt corner. Learn from others... sooner or later, that if you need more capacity than one 12 volt battery can provide, you should be at a higher voltage.
--vtMaps
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Right now I’m running a Baker Monitor, that was installed in 1975. My generator powers a DC motor, in between there is a converter to change the AC to DC. It pumps to a 2500 gallon redwood water tower. From there I have low flow into my dwelling (an old caboose) I use that water for showering and washing dishes but I carry fresh water in a jug from the well for drinking. So the plan is to install a pitiless adapter and a direct line into the caboose, and into a pressure tank so I don’t have to worry about freezing and can have fresh water and normal flow.
I inherited this property from my dad and it’s been a continuos education trying to keep everything going and trying to understand what he was doing and how. I have pretty low needs and up till now have seen no reason to change from 12v. I would like to add more solar panels though and I know higher voltages are more efficient, so it's something else to research for sure.
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The interface box (CU) does a few more things also like vary the house pressure which is important with the advent of sprinklers in the home for fire code on new homes in my state and others to follow. The differences are below from Grundfos.
SQ, SQE pumps feature an innovative motor design
incorporating permanent-magnet technology. By
combining permanent-magnet motors and a Grundfos
micro-frequency converter, we are able to deliver
unmatched performance and the ability to control and
communicate with the pump in ways never before
possible. A few of the features that result from this
combined technology are Constant Pressure Control,
Soft-Start, and Integrated Dry-Run Protection, but
these are just a few of the features these pumps offer.
SQ pump models operate at a constant speed much
like today’s conventional pumps. The difference is that
SQ delivers the benefits of an electronically controlled
permanent-magnet motor that cannot be achieved with
a conventional induction motor.
SQ pumps are available for single-phase power; a
simple 2-wire design makes installation easy.
SQE pumps are equipped with a Grundfos "Smart
Motor." Like the SQ models, SQ pumps have a high
efficiency permanent-magnet motor — but we add the
ability to communicate.
The "Smart Motor" communicates via the CU301
status box through the power leads.
It is not necessary to run any additional wires down the
well. Communication with the pump provides Constant
Pressure Control and the highly useful ability to
change the pump performance while the pump is
installed in the well. Like the SQ motor, this is also a 2-
wire motor designed for single-phase operation.
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http://members.sti.net/offgridsolar/
E-mail [email protected]
But before that happens, you need to get the pump curves for the voltage/head you are planning on.
Will the flex cycle on and off, on it's own, to maintain pressure or will it run continuously until the batteries go flat at 1AM ?
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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