Help with Solar Pump system design? Please!

**Naptown** · 04-03-2012, 02:15 PM

Then consider using an appropriate size direct burial aluminum service entrance cable.
Do the voltage drop calculations to the well head and then connect the copper to the aluminum using approved lugs in an approved enclosure.
You could use the same trench as the water line is in just separate by at least a foot vertically with the wire on the top

A 1000 foot roll of # 4 or #2 will cost about $300.00
So you will have about $1000 cost to run the electric which will run the pump 24/7
Or invest a huge amount in batteries panels etc which will cost on the order of 4-5 times as much not including the additional costs for that expensive pump.

If you insist on solar I suggest a water tower to gravity feed to the house with perhaps a small pressure pump running on grid power. That way you pump during daylight and the pump shuts down at night.

**jungleexplorer** · 04-03-2012, 02:37 PM

Thanks. A friend of mine said it would be cheaper to go solar then to run wire, but I thought he did not know what he was talking. Solar is great but PV panels will have to come way down for it to be a feasible alternative for household use.

**Naptown** · 04-03-2012, 02:46 PM

Originally posted by jungleexplorer

Thanks. A friend of mine said it would be cheaper to go solar then to run wire, but I thought he did not know what he was talking. Solar is great but PV panels will have to come way down for it to be a feasible alternative for household use.

It's not the PV panels that are the issue
it is all the battery stuff and expensive pump that make it expensive.

**Sunking** · 04-03-2012, 04:15 PM

Originally posted by jungleexplorer

Thanks. A friend of mine said it would be cheaper to go solar then to run wire,

He just does not what he is talking about. Off-Grid Solar should only be used if there is no other option.

**Wy_White_Wolf** · 04-03-2012, 05:05 PM

Originally posted by jungleexplorer

..2. My purpose. I will be using this well for all of my household needs as well as irrigation for a garden. To keep it simple, I want to build a system that can pump 4 GPM continually 24 hours a day. I plan on using a 50 gallon pressure tank at 60 PSI pressure...

Off the top of my head I'd say you're looking at $25 to 30 THOUSAND if you want to do that on solar.

Now if you want to install a cistern and use a solar direct pump to fill and a gravity feed or second pump to pressurize everything one might get by for much less.

WWW

**Mike90250** · 04-03-2012, 09:35 PM

Solar and battery, for 24/7, is out. Or will be VERY pricey. Even for a lottery winner!

I agree with the trench and #2 aluminum wire. And specify a 240VAC pump with a 40-80 gallon pressure tank, at the pump (puts all the controls at one spot). The larger the pressure tank, the fewer on-off cycles for the pump. Starting is quite hard on pumps, so anything you can do to spare them, is good.

You will only need 1/3 or 1/2 hp pump, to supply 4GPM for your depth and pressure you want. Too large, will pump your well dry, and most "standard" pumps have no easy sensor for "Run Dry" shutdown. There are some electronic controllers that can sense a free-wheeling pump, and shut it down, but a 4GPM well is pretty small. Insist on inspecting the "Pump Curve" for the pump & motor combination you choose, to make sure it's what you need, and not what is overstocked at the moment.

**Naptown** · 04-03-2012, 09:41 PM

And don't forget if the tank is located at the well to compensate for the pressure drop and loss of volume from 700 feet of pipe.

**jungleexplorer** · 04-04-2012, 12:30 AM

Originally posted by Wy_White_Wolf

Off the top of my head I'd say you're looking at $25 to 30 THOUSAND if you want to do that on solar.

Now if you want to install a cistern and use a solar direct pump to fill and a gravity feed or second pump to pressurize everything one might get by for much less.

WWW

Holy Smoke!!! I was thinking it would cost around three thousand, not thirty! Thirty thousand just for a 12v DC water well pump to produce 4 gpm, are you serious? I talked with a dealer that said he had a Shurflow pump kit that would do 2000 gallons a day for $1,400.00, including batteries and PV panels. I knew it would cost more to do what I wanted, but I had no idea it would cost 20 times as much. Running wire seems like a bargain now!

**russ** · 04-04-2012, 12:57 AM

In a similar situation Mike ran wire and he is off grid - be well aware that you are being fed bull by your friend and sales people.

**jungleexplorer** · 04-04-2012, 01:32 PM

Originally posted by russ

In a similar situation Mike ran wire and he is off grid - be well aware that you are being fed bull by your friend and sales people.

Not that I am questioning the advice I am getting here, but where is the expense at that equals 25 to 30 thousands. I mean the pump I am looking at runs $830 and I can get Kyocera KD185GX-LPU 185 Watt panels for $300 from Northern Arizona Wind and Sun. I don't know about batteries, but I just don't see where you get to $30,000.00 to run a pump. I would expect 30,000.00 to be what I would spend to run my whole house, not just one little 12 volt water pump. Where is the hidden cost here?

**Naptown** · 04-04-2012, 01:58 PM

Originally posted by jungleexplorer

I moved out to a rural area and after several test drills, we finally found water. But the well is located over 700 feet from grid power and the cost of running the appropriate sized copper wire is pretty high. So I am looking at going with a solar pumping system. I have looked around and it appears that each system has to be custom designed. So here I am to ask for some help from people that know a lot more about this subject then I do. I know this can get complicated, so I will try to help by providing as much information as I can.

First off though, could you just give me the basic list of components I would need to build the system; for instance, 1. Pump, 2. PV panels, 3. Controller and so on and so forth.

Here are the specifics of my system:

1. The well. My well is 100 feet deep. It had about 70 feet of water in it when not in use. It has a maximum sustained production rate of 4 GPM.

2. My purpose. I will be using this well for all of my household needs as well as irrigation for a garden. To keep it simple, I want to build a system that can pump 4 GPM continually 24 hours a day. I plan on using a 50 gallon pressure tank at 60 PSI pressure.

I have been looking around at pumps and found the SunPumps SDS-Q-135. It looks like it will produce the volume I would need for my 100 foot deep well, but I can't find any statistics for it when it comes to using it in a pressure system.

Could someone help me design a system to fit my needs? Thanks.

Originally posted by jungleexplorer

Not that I am questioning the advice I am getting here, but where is the expense at that equals 25 to 30 thousands. I mean the pump I am looking at runs $830 and I can get Kyocera KD185GX-LPU 185 Watt panels for $300 from Northern Arizona Wind and Sun. I don't know about batteries, but I just don't see where you get to $30,000.00 to run a pump. I would expect 30,000.00 to be what I would spend to run my whole house, not just one little 12 volt water pump. Where is the hidden cost here?

the statement in red above. The battery bank required to run that would be huge. Remember in winter you only get maybe 3 sun hours a day.
Now lets say that pump draws 10A at 24V
Thats 240 WH per hour or 5760 Watt hours per day
In order to have enough battery to sustain 2 days of no sun without discharging more than 40% would require a battery capacity of 28,800 Watt hours.
so you would need a battery bank of 1200 AH @24V or 600 AH at 48 volts. This would be 12 200AH batteries at 12v ea
Now you need to be able to recharge those batteries in one day after the 2 days of rain to prevent damage to the batteries.
So in two days you used 11,520 WH of power. With an MPPT controller the losses and calculation are as follows
WH *1.5 / sun hours
So with 3 hours of sun worst case
11,520 x1.5 / 3 = 5.67KW of PV round that up to 6kw.
Run the numbers yourself with real numbers based on the actual pump. It may not be 30K but it is substantially more expensive than running electric with a standard 240V AC pump

**Mike90250** · 04-04-2012, 03:06 PM

You asked for a HUGE amounbt of power. If you belive you will only have the pump running 2 hours total, out of a 24 hour day, that would be a much smaller system.

You will need a Pure Sine Wave inverter, or plan on both: a) replacing the pump early. b) adding another 20% to your power budget.

The 1/2 hp franklin motor I have, consumes from the inverter, 1,000 watts. Theory says it should consume 400watts. The difference is in losses that simple caculations don't show. (power factor, motor efficiency....)

We don't know what your water consumption plan is, I pump for up to 6 hours in the summer, for irrigation. Winter is only expected to be about 10-20 minutes a day.

**Sunking** · 04-04-2012, 03:36 PM

Originally posted by jungleexplorer

Not that I am questioning the advice I am getting here, but where is the expense at that equals 25 to 30 thousands. I mean the pump I am looking at runs $830 and I can get Kyocera KD185GX-LPU 185 Watt panels for $300 from Northern Arizona Wind and Sun. I don't know about batteries, but I just don't see where you get to $30,000.00 to run a pump. I would expect 30,000.00 to be what I would spend to run my whole house, not just one little 12 volt water pump. Where is the hidden cost here?

Ya but how much are 20 of those panels, and a 2000 pound battery?

What you are not getting is you want a huge amount of power. It is going to cost you anywhere from $3000 to $5000 for each Kwh you want per day. Of that 3 to 5K is $1000 for batteries that need replace every 3 to 5 years. So if you need 10 Kwh per day you are looking at $30 to $50K depending on your location. You will also need a generator.

**jungleexplorer** · 04-04-2012, 06:41 PM

Okay now I get it. I did not make my self clear in my first post. I am not talking about running the pump 24/7 365 days a year. I live in central west Texas with no trees and have about 330 sunny days a year. Since the pump will be hooked to a 50 gallon pressure tank, it will never run 24/7. It will run to pressurize the tank and turn off until the pressure drops to the turn on point. Some days will be heavier then others with almost no water usage at night and no irrigation usage in the winter. When I said I wanted system that could pump 4 GPM 24/7, I just meant I want a system that has the capacity to do this if on a very rare occasion I needed to do this for a day.

So let's say, that I needed a lot of water one day during the summer. Assuming I have enough PV panels to run the pump (see pump specs below) and charge the batteries at the same time, the only question is how much battery storage I would need to run the pump for a single night (40% discharge).

The pump I am talking about is the Sun Pump SDS-Q-135. Here are the specs on it copied from the spec data sheet (http://www.dcpower-systems.com/uploa...ts/22762_2.pdf).

22762_1.jpg

The specifications at full voltage (30V) are as follows:
Maximum Flow Maximum Head Maximum Power
Model GPM lpm Feet meters Motor Watts
SDS-Q-135 5.0 19 100 30 184

Voltage rating is 12

Help with Solar Pump system design? Please!

Help with Solar Pump system design? Please!

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