Solar Powered Drip Irrigation System

ahunternjahunternj Posts: 9Registered Users
I had a thought of combining two "green" ideas but wanted to come up with a budget and plausibility exercise. I wanted to post here to draw from your solar expertise.
What I have:
In Central NJ I have a 20’x 20’ fenced in garden with rows 2’ apart (9 rows) of mixed density (row crop and high density) vegetables.
The problem:
Watering this garden is a problem since the house is about 1/8th of a mile away and water has to be carted back and forth.
Proposal:
I was thinking of installing a well, solar powered well pump, storage tank, and drip line irrigation system.
Goals:
I want to run the system for 1 hour a day everyday. Each dripper will supply .5GPH @ 20PSI. The system will contain ~200 drippers for a total of 100GPH @ 20PSI. I wanted to include a 250G storage tank to account for a “shady” day. It will have a float stop to turn off the pump to avoid overfilling. I figure a storage tank is a much cheaper alternative than batteries. I am looking to spend about $2000 for all equipment (not including the well drilling). The well will be 50ft deep.
Questions:
After looking at some DC powered pumps online, I am having trouble finding specifications that correlate with a PV panel. For example I found a pump (SunPumps SDS-D-128) which looks good but will a single Kyocera Solar KD-135 power it or will I need a bigger one like a SolarWorld SW-175 or more than one? Again, my goal is to fill about 100G/day. I would probably also use a SunPumps VCA pump controller to manage the pump.
My second big question is a plumbing question and whether the weight of the water in the tank can provide 20 psi on the ground or mounted no more than 6’ in the air? If not, I guess I would need a pump for that as well and some sort of timing device.
If this is way overkill, let me know but also this garden could be expanded to three times it’s width in the future with a new fence. Also, the $2000 budget is pretty firm. Right now I see the pump costing about $700, pump controller $400, solar panel $400, tank $300, drip equipment $100, mounts & wiring $100. I can fabricate a stand for the tank, panel, and controller with some unistrut on a concrete pad.
Let me know if I am on the right track and if you have any answers to my questions. Also if you have done anything like this or have some helpful insight it would be appreciated. I would like this in place by next year if it is feasible.

Comments

  • mike95490mike95490 Posts: 6,514Solar Expert ✭✭✭✭
    Re: Solar Powered Drip Irrigation System

    Water pressure:
    0.43 pounds/square inch for each foot of elevation 6' off the ground will give you less than 3 psi.

    You may be able to run the drip on lower than 20 psi, but it would be a much slower rate, may have to leave it on 24/7

    Solar pressure pump will be very expensive.

    Well drilling, is it permitted in your area ? What is a common depth for water? Any bad stuff generally in the water, Boron, iron....
    A solar well pump is feasable, to fill your tank and keep it topped off.
    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 ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    Yes, we currently have a well at our house for drinking water and we can drill another one. The water quality is fine, but a little hard on the pH side. Well water is what we are using now, just from our house and carted over.
    Maybe another thought would be to eliminate the storage tank and just use the well pump for pressure. If I read the pump specs correctly, this time looking at the SunPumps SQS-Q-135, it will pump 45 PSI (21PSI for ~50ft lift from well + ~20PSI for drip system) @ 15V / 4.61A which a Kyocera KC85TS looks sufficient (peak 17.4V/5.02A). It will pump 1.7GPM which is just over my 100GPH goal.
    Due to a less consistent output because of the elimination of the storage tank, I might want to put it on a 2 hr timer instead of running it 1 hour. The pump is more expensive, the panel the same price, but I can save $300 on the tank so I think I am still making out. The only worries I have would be a greatly shortened life of the well pump since I would be doubling the PSI.
    Any thoughts?
  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    Or could I spend $100 and get a cheap pump like a Shurflo 8000 and run that off the same panel to pump out of the expansion tank? Maybe a relay that would change from well pump to tank, then back? Or just wiring them in series with a timer on the tank pump? Even that Shurflo is a bit over kill so I think reducing its voltage by running it with the well pump will help keep things in control. That is if I remember that old saying "Amps - Series, Volts - Parallel" correctly. I assume it is more important to keep the amps constant between the pumps and split the voltages.
  • Dave AngeliniDave Angelini Posts: 2,475Solar Expert ✭✭✭✭
    Re: Solar Powered Drip Irrigation System

    If you have power at the house. Pump water to a storage tank at the garden. Use a $100 shurflo pump, a $150 15 watt solar panel, a $75 Kirkland battery deep cycle group 27, and your normal drip irrigation with a battery timer.

    Carting water around by hand? Is this NJ or Cental America?
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    Well, that is a much simpler solution but it will not work as there is a road between our house and our garden so I can’t lay a pipe between the two. If this is getting built it has to be built in the garden. I hadn’t thought about using a battery to run the pump and using the panel to charge the battery. I guess the money from the battery system would be made up by being able to use a smaller panel.
  • mike95490mike95490 Posts: 6,514Solar Expert ✭✭✭✭
    Re: Solar Powered Drip Irrigation System

    Adding a battery, and recharging it, will cost you power in the long run.
    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 ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    Sure, because the battery loses efficiency while charging and over time.

    Plans are in the works now to increase the size from 20' x 20' to 80' x 80'.
    Obviously I will have to increase my budget.
    Napkin math tells me I will be growing a 76'x76' area on 2' row centers = 38 rows.
    76' rows * 38 rows = 2888' drip line = 1444 GPH with .5GPH drippers every 1'
    I plan to run a 1" feeder line perpendicular to the rows with 38' runs down each side. I will need a tank pump now with a dedicated panel and 3 500G tanks.
    I will use a normal (up=open circuit) float switch at the top of the tanks to turn the well pump off and a reversed float switch (up=closed circuit) near the bottom to turn the tank pump off. I should still be OK with the panel and well pump previously selected. I will need to double my budget for additional tanks, pumping, panels, and piping. That's actually not bad considering I am quadrupling my sq.ft.
  • mike95490mike95490 Posts: 6,514Solar Expert ✭✭✭✭
    Re: Solar Powered Drip Irrigation System

    You may still come out ahead, if you go with a small genset, to run the well pump for filling the tanks.
    I don't know if there is a solar "pressure booster pump" Small RV pumps are for a gallon or so, to wash dishes, not a 3 hr soaker hose run.

    http://store.solar-electric.com/shacdcwapu.html
    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 ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • solarvicsolarvic Posts: 954Solar Expert
    Re: Solar Powered Drip Irrigation System

    Another idea! What kind of road seperates your house from your garden? Where I live in Pa. they have been drilling gas wells all the time and go under the road a lot. If you are on a country road you might be able to get someone to bore under the road for you so you can run a water line from the house at a lot lower cost than drilling wells and all the equipment you are proposing. Also there are people that horizontal bore under the ground for ground source heating that probably could get water lines under the road for you. I know someone that direct tv paid for one of those guys to bore under thier blacktop drive and it only cost about $175.00. S:Dlarvic
  • Dave AngeliniDave Angelini Posts: 2,475Solar Expert ✭✭✭✭
    Re: Solar Powered Drip Irrigation System

    I would also go with solarvic and go under the road. Local telephone companies do this all the time. Just use a galvonized pipe. You may also want to consult a master gardener on mulching techniques and low water use gardening. I have seen huge gardens powered from small RV pumps. No one uses three hour soak times offgrid because the pumps cannot take continuous operation. There are so many ways to do this if you are there in the garden daily. If this is a big city project where you are not home (at the office) then you probably should just dig a well and spend the stimulous money! Good for the economy and all....
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    Thansk you for your advice on this subject. I am currently in the process of getting well quotes. I realized this whole time I was calculating on 2' row centers when it should be 3.5' row centers (mostly heirloom tomatoes) so that drops me down from 1444 gallons per day to 800. As far as the pumps, aren't the "surface mounted" pumps listed on this site from companies like SunPumps and Dankoff rated for continuous duty? If the well comes out too much $$$ or if the idea won't work, then running a line under the road will be the only choice. It's also a little more than just burying the pipe under the road, it would have to be buried all the way back to the house and again on the other side of the road. I don't want the pipe just laying across the lawn! Granted pvc pipe is cheap and so is renting a ditch witch for a day, but it's not nothing either. I didn't want to tax the well in our house which was one of the original drivers of the whole idea but we'll have to see how the quotes come in.
  • Dave AngeliniDave Angelini Posts: 2,475Solar Expert ✭✭✭✭
    Re: Solar Powered Drip Irrigation System

    The devil is always in the details is it not? Good Luck!
    PS our heirlooms are in the ground and barely escaped monday night snow. Yep, definately global warming!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • System2System2 Posts: 6,290 admin
    Re: Solar Powered Drip Irrigation System

    Don't know if it is too late to reply to this, but I sure hope that you have not spent a fortune. It is entirely possible for you to just use a simple pump system fueled by a PV panel to pump water to a holding tank with a flow valve & piping to your garden. If you are still interested please let me know and I will be happy to share more information with you. We used this method to irrigate an entire community garden (however we are not using drip irrigation as we are tilling the entire acre each year) so we instead use gravity from the tank to feed about 15-20 spigots throughout the garden. Our set up is much larger than what you would need and cost us under $4000 as we purchased an 800+gallon tank, solar panels, 2 pumps, etc, etc....
  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    No, I haven't spent anything on this yet. Right now I am busy at work and around the house. My plan is to buy things in the fall/winter and have everything ready by the spring. Please share your experiences here for my benefit and all those who also may be interested!
    In other news I have lost about half of my ripe tomatos this year to blossom end rot! Trying to remedy it by adding lime with the water but it is very dissapointing.
  • System2System2 Posts: 6,290 admin
    Re: Solar Powered Drip Irrigation System

    I will give you more specifics on the irrigation as soon as I can gain access to those files & links, but in the interim please take a look at this link about Late Blight. Hope that some of this information helps! I will be back in touch! :D
  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    What I have is different then the fungal blight. What is happening here is blossum end rot due to a lack of calcium being absorbed by the plant. This is commonly due to too much water, not enough water, too much fertilizer, or an overused plot of land. It has been really dry here this year so it would seem to be the lack of water causing it. It has really only rained a decent amount twice in about 3 months.
  • spurlocktoolsspurlocktools Posts: 11Registered Users
    Re: Solar Powered Drip Irrigation System

    You might want to look at the Nemo pumps: http://nemosolar.com/dcsubmersiblepumps/
    These are a Flojet surface pump installed into a waterproof case, basically similar to the ShurFlo 9300 submersible pumps but around 1/3 the price at $240 ppd. They have the same longevity problems as the Shurflo (brushes, diaphragms and bearings can wear out) but the low price might make sense for your limited use. I have used one for several years of intermittent irrigation with no problems. They are user rebuildable as well. Mine is on an intermittent timer (low producing well needs recovery time) and pumps directly into a drip system.

    Because the pump output will never match the emitter output exactly, you need somewhere for extra water to go, so I have a T at the well head leading to a tank a few feet above ground. So during pumping, extra water beyond the drip system's usage goes into the tank, which then continues feeding the system when the pump cycles off. Works for me for low budget limited water needs situations.

    If pumping PV direct, always use a linear current booster which will allow the pump to start in low light and keep running during cloudy conditions, thus yielding much more water.

    I use both individual emitters and drip hose with emitters built in every few inches, and both work fine for me at 4' head pressures. So you can get by with a low elevation tank by ignoring the stated 20 psi minimum pressure and just using longer run times.
  • ahunternjahunternj Posts: 9Registered Users
    Re: Solar Powered Drip Irrigation System

    That sounds almost exactly what I would like to do.
    Could you provide a diagram/schematic or just describe your system in a little more detail?
    My main questions:
    How much area do you irrigate?
    How long do you run your system for?
    How big of a tank do you use?
    What is your solar panel system (which panel(s), 12v or 24v)?
    On the Nemo page you linked are you running your system like #5 but with a T before the holding tank with the other branch going to the drip system? How did you replumb the tank into the drip system? Just a valve you have off while pumping and you open it when want to water but not use your pump?
  • spurlocktoolsspurlocktools Posts: 11Registered Users
    Re: Solar Powered Drip Irrigation System
    ahunternj wrote: »
    That sounds almost exactly what I would like to do.
    Could you provide a diagram/schematic or just describe your system in a little more detail?
    My main questions:
    How much area do you irrigate?
    How long do you run your system for?
    How big of a tank do you use?
    What is your solar panel system (which panel(s), 12v or 24v)?
    On the Nemo page you linked are you running your system like #5 but with a T before the holding tank with the other branch going to the drip system? How did you replumb the tank into the drip system? Just a valve you have off while pumping and you open it when want to water but not use your pump?

    My Nemo pump is on a VERY low producing well (about one pint per minute) so my system will be a bit different from what you would do to handle more water. But the basic principles of supply line Teed into a slightly elevated holding tank should apply. Because this well produces so little water, I run it on a switching power supply salvaged from an old desktop computer. These are very efficient. I just use the power supply's 12v lead. I made a little timer that turns the power supply on for about 30 seconds every 11 minutes. This way I can run it 24 hrs per day and get around 80-100 gallons during that time. Pumping daylight hours only with PV power would not yield nearly as much, and would be a waste of PV panels. I just run four 2.5 gal per hour emitters off of this for a tiny bit of supplemental irrigation here and there.

    To answer your other questions:
    The plumbing is just 5/8" drip tube running from the pump about 200 ft. to the emitters. I put a T in the line between the pump and emitters. A hose goes from the T to two 55 gallon plastic barrels. The barrels are elevated about 10 feet and have male hose fittings at the bottom edges to accept the line from the pump and to connect the two barrels to make 110 gallons of storage. There is no valve in the tank. When the pump comes on it produces more water than the four emitters will use, so the water level rises in the barrels. When the pump shuts off the level in the barrels drops as they continue to feed the emitters. I've matched the emitter consumption to the well output so the emitters are always running even though the pump runs only 5% of the time. If the well produced more water I would need a larger tank and a "tank-full" shut off switch so the tank would not overflow.

    I have two other wells that do run on PV panels and produce more water. One uses s ShurFlo 9300 pump which is hooked up essentially as described above, except that the tank is 270 gallons, and the pump has a controller and a "well dry" pump shut off as well as a "tank full" shutoff. This one is also just supplementary irrigation using emitter tubing circled around orchard trees two at a time and moved daily.
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