Water for a Community Garden

Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
Hi,
I am new to solar power and would appreciate a lot of help. I am planning a community garden (45'x50') in my association and need a way to provide water for the garden. It is in a remote location but there is a lake 70 ft away from the garden. I am thinking of using a 12v submersible pump that will run off of 12v batteries, and will be charged by a solar battery charger or solar panel. The total run of the water line would be about 150ft and the pump will have about 5ft rise in elevation. There will will be 2 bibs with garden hose attached. My question is what size pump would I need, how many batteries and type, what size solar panel or solar battery charger and how to control the pump when someone wants to use the garden hose. Would I need a pressure tank set up or can it be done by a switch. There is a concrete overflow for the lake that I think I can install a pump next to. Also can you give me an estimate on the cost because I have a budget I have to stick to.
  Like I said I am new to all this so be gentle with me .
Since I do not see anyway of posting a picture I will give a link of a pic I took off of google earth
http://oi63.tinypic.com/fcp9y1.jpg

Thank you for any help you can give

Comments

  • BB.BB. Super Moderators, Administrators Posts: 28,768 admin
    You should be able to add photos (there is a black square/piece of paper with the corner pulled back in the edit window above)--And you should be able to drag and drop the photo directly into the edit box:
    bra hrefhttpoi63tinypiccomfcp9y1jpg target_blankView Raw Imagea
    Note, the above picture has "white space" around it--would need to be edited to get rid of this for a "clean" drag&drop. But it does work.

    When designing a solar power system--We really need to understand your loads and where it will be installed (nearest large city such as Scranton PA or wherever--How many hours of sun you will have, and what is your pumping season)... And with water pumping, there are many ways to design a system (pump to pressure, pump to a pressure tank, pump to a cistern then a pressure pump, pump to elevated tank, etc.).

    Also, how far from the solar panels+battery bank to the pump? Longer wire runs typically work better at higher voltages (24 volts or other).

    In general, if you are looking for a "cheap" off grid solar power solution--Ideally if you can pump to an elevated tank/cistern (on hill, or 20 foot tower), that basically makes the water tank your stored energy instead of the battery bank. More or less, if you can design a battery less system, the price of solar power will be about 1/4 the cost of an equivalent power system with battery bank (batteries are expensive, only last 3-5 years for golf cart batteries, require monthly battery maintenance, etc.)--At the cost of elevated water tank and (more expensive) direct connected solar power pump.

    So--Before designing the solar power system, can we have more information on your pump/hours of use per day. Also, will this be "flood" irrigation, low pressure drip, or higher pressure sprinkler type system (more pressure/volume, larger rated pump, more electrical energy needed). And how much water/how many hours of pumping per day (i.e., 2 hours pumping * 8 amps = 16 AH @ 12 volts).

    You pump itself can run from an RV type diaphragm pump (brushes and diaphragms last limited amount of time, but the pumps are cheap). To high end submersible pump ($2,000+?) that can take solar panels/dc battery bank/AC inverter/AC genset and last 10+ years.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,320 ✭✭✭✭✭
    Are you a gardener ?  The reason I ask is that makes it easy for you to calculate how much water you need.  Hard enough to be gentle/design  for someone who does not know what they need?
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    Are you a gardener ?  The reason I ask is that makes it easy for you to calculate how much water you need.  Hard enough to be gentle/design  for someone who does not know what they need?
    No I am not a gardener but I can tell you we are planning to have 30 4' x 8' plots, if that helps. So if it is dry I figure a good amount of water will be used.
  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    edited July 2016 #5
    Q. How many hours of sun you will have, and what is your pumping season)

    A. It will have a full southern exposure

    Q. how far from the solar panels+battery bank to the pump?

    A. Around 80'

    Q can we have more information on your pump/hours of use per day.

    A There will be 30 8' x 4' garden plot that will need watering especially in dry conditions

    Q. will this be "flood" irrigation, low pressure drip, or higher pressure sprinkler type system 

    A. basically it will be people using a garden hose

    Q  And how much water/how many hours of pumping per day

    A really not sure about that one, a rough guess would be about 4 hours total a day

    hope that helps
  • BB.BB. Super Moderators, Administrators Posts: 28,768 admin
    OK... I can take a guess:

    https://bonnieplants.com/library/how-much-water-do-vegetables-need/

    A good general guideline is an inch of water per week, either by rain or watering; in arid climates, it is double that. In hot weather, vegetables need even more water, up to about ½ inch per week extra for every 10 degrees that the average temperature is above 60 degrees.

    By definition, the average temperature is the daytime high plus nighttime low, divided by 2. So, if the high is 95 and the low is 73, the average is 92 + 73, divided by 2. The answer is 82.5. In this case, the garden needs at least another inch of water. This explains why most vegetable gardeners in hot climates just laugh at the “1 inch of water per week” recommendation. That simply doesn’t work in really hot weather for squash, eggplant, tomatoes, and other crops that need lots of water and have big leaves that wilt easily.

    So, lets go with 2" of water per week, and 60 gallons of water per 100 sq ft per inch of water.
    • 30x8'x4' = 960 sq ft
    • 960 sq ft * 2" of water per week * 60 gallons per 100 sq ft. per inch of water = 1,152 gallons per week
    • 1,152 gallons per week / 2 days per week (worst case) = 576 gallons per day
    A 10 gpm pump (pretty large pump, a typical garden hose is probably 5-10 GPM @ 40 to 60 PSI) would be ~1-2 hours of pumping per day, 2x per week (just a really rough estimate of what your garden space would take). You should probably design for 2x more at least (we are dealing with people). If people will be spread out (i.e., over 6-7 days per week), your daily pumping may be less.

    Before I make any more guesses, do you have a link to a pump you are thinking of using?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Solar Expert Posts: 1,257 ✭✭✭✭
    My preferences are battery-less, low pressure drip (much more energy efficient),  automatic watering, soil moisture sensor controlled.  A wild guess - 750 gallons every 3 days.

    I am available for custom hardware/firmware development

  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    BB. said:

    Before I make any more guesses, do you have a link to a pump you are thinking of using?


    This is all new to me so I am trying to get some idea how to set this up. Any recommendation will help for my setup.

    Thank you

  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    Mik_Kan said:
    BB. said:

    Before I make any more guesses, do you have a link to a pump you are thinking of using?


    This is all new to me so I am trying to get some idea how to set this up. Any recommendation will help for my setup.



    I was looking at an On Demand pump since we are dealing with people who are looking at convenience of just spaying water on their plants. I don't know if they make a submersible pump like that.
  • BB.BB. Super Moderators, Administrators Posts: 28,768 admin
    Lets get down to brass tacks... How much are you willing to pay for a pump? $100? $800 too much? $2,000+ too much? (more expensive pumps will last longer and usually have higher flow rates).

    You can pull about 10 (perhaps 15) feet lift with a pump--Can you have a "surface pump" (rather than in well/under water pump) on the bank of the lake or possibly even in a float?

    Can you see a two pump solution... A "slow pump" from lake to a 600+ gallon cistern (1 gallon per minute is 60 gallons per hour--6+hours of sun will give you close to 360 gallons per day to the cistern)? And a local pump to pressurize (perhaps even a cheaper RV pump may work well).

    If you can experiment with your hose and a pressure valve and see what an acceptable pressure would be (i.e. 2 gpm @ 40 psi or what)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    BB. said:
    Lets get down to brass tacks... How much are you willing to pay for a pump?
    I am on a tight budget so I would say around $200 for a pump.
    I saw this pump this morning and was wondering if this would work for my setup. I just have a problem with someone coming by and messing with it if it is above ground and they see it. I do not know if something like the pump I looked at will handle the length of the pipe run even though it will be on level ground with no rise.
    Like I said this whole thing is new to me, so I am just trying to see what would work. I would hate to do something and spend the money just to find out I have to toss everything out and start again.

    http://www.seaflo.us/product/diaphragm-water-pump-51-series/?gclid=Cj0KEQjwlNy8BRC676-W0JezxbwBEiQA4Ydg0QYdTtivlYWpec3T0sofOlxihBa34-ax9pSctAfADhAaApAc8P8HAQ

  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    If I do use a submersible pump would I have to switch it on and off when I want to use it? Like I said I am dealing with people who probably just want to come and water their plants without flipping switches or forgetting to turn the pump off.
  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    Let me add that I live in Northeast PA this pump will be used maybe 5 months out of the year.
  • jonrjonr Solar Expert Posts: 1,257 ✭✭✭✭
    There is a lot to be said for submersible pumps - fewer problems with priming, theft, corrosion, flooding.   Budget sounds very tight - any chance that people pull their car up to the plot and could plug something into the cigarette lighter?

    I am available for custom hardware/firmware development

  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    I would like to do this for $500 to $600 for everything it is a 150 run on a level ground the only rise will be the 2 foot that the pump is in the water. Even if I can get 25 psi at the hose that should be decent I think to water plants.
    If I do this with a submersible do I have to switch the pump on and off?
  • BB.BB. Super Moderators, Administrators Posts: 28,768 admin
    You can use a water pressure switch.

    What also may help is to get a mechanical twist timer. Twist to 1-2 hours of pump time. Then shuts off. Can help protect against somebody leaving the hose on and killing the batteries.

    That price is pretty low. How much per year for maintenance (battery replacement and pump overhaul funds).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Mik_KanMik_Kan Registered Users Posts: 10 ✭✭
    BB. said:

    That price is pretty low. How much per year for maintenance (battery replacement and pump overhaul funds).

    -Bill
    This is just for installation, after that the association can worry about it. I have to make a proposal to the finance committee and right now since there are other projects going on, my limit is $5000. I am really tight on materials right now, and may not be able to do everything I want to do. If I have to cut back on some garden boxes and leave room for additions later on that may work out. Can you give me some idea of the cost I am looking at and what kind of pump, batteries and solar panel I will need that will help a lot. How much do you figure the yearly upkeep cost will be? Thank you for putting up with my ignorance on this subject and I appreciate the help you are providing.
  • mike95490mike95490 Solar Expert Posts: 8,192 ✭✭✭✭✭
    Water pumping and gardens
     Forgo the hose and go for a drip system, it will save water, and therefor energy,
    Do you have any height to store water in an elevated tank, either a water tower like for an old time steam locomotive, or 20 feet up a hill?
     Pumps are most efficient when loaded properly and pumping to a tank or cistern is far more efficient than using a "Pressure Tank" with air bladder.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • AnawaAnawa Solar Expert Posts: 211 ✭✭✭
    I have a garden about twice the size you are planning that is watered entirely via solar-pumped water. I believe that determining your water delivery system is a first step in engineering the kind of "solar" system to implement. Deciding between a hose or drip system involves several considerations. After much time spent engineering "how" to water (hose or drip irrigation), the decision to go with drip has proven to be the right thing to do for me.

    There are advantages and disadvantages with both of the water delivery systems when solar energy is involved. Some of the basic principles of a hose system is that it is less complicated, more flexible, but requires the water to be pressurized which involves more equipment, possibly batteries, and more electronics. A drip system can be functional by gravity alone, efficient, programmable distribution, but requires the water to be stored (usually in tanks) at an elevation that provides enough pressure for water to flow, requires very clean filtered water, and requires re-installation of the tape (not header pipe) each season. For what it's worth, you can install a drip system header at each box that can be turned on/off depending on if it's being used. These are just some of the factors to consider in your decision making.

    Some other things to consider that are not directly associated with the system engineering are: Who is going to be the person responsible/accountable for keeping the system operational on a full time basis? Any system will require annual maintainence/upkeep, how will this be handled? Is it the responsibility of the Association to water the plots or just provide the water? 

    Since you plan to draw water from a lake, an important requirement is that it be filtered. Depending on the whether you hose-it or drip-it, determines the screen size of the filter cartridge. 

    Paul
    in Georgia

    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
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