Announcement

Collapse
No announcement yet.

Advice for off grid farm system

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Advice for off grid farm system

    Hello everyone, let me just start out by thanking anyone who helps me out here and also apologizing for my lack of understanding. I've been reading as much as I can in the past couple weeks to months, but still haven't come to any real conclusions for my needs. Here's my situation:

    I've recently began farming on a 4 acre property that has no access to electricity and never will. This is not my decision but it remains the circumstance so I must move forward with my acceptance of that. My partner and I have built two greenhouses, figured out our irrigation using a gas powered suction pump to irrigate from a creek, and have been using a gas powered honda generator for the bulk of our temporary electric needs. With that said, we're at a point where we will have a couple things that need to run 24/7 that we'd like to take advantage of solar for. In addition, we're looking for a system that we can build upon as needed, if we ever need more demand of power.

    At the moment, the only thing we are looking to power is a small fan that inflates the double layer of plastic to our greenhouse. This is a larger computer fan which runs on 12v at .52A or 6.24W. Within the coming month we will be putting in a deer fence. The chargers for the deer fences come in AC, DC and also built in solar. I'd like to take advantage of the stand alone DC charger, rather than buying one with a small solar panel inside, so that I can tie in into our system. The issue with these is I haven't found much information on the requirements, they state simply that a charger should run for 2 weeks to a month on a battery that is fully charged.

    I'm not sure what else we will be adding in the future, possibly some temperature controllers or fans to the greenhouse if possible, but I'd just like to have that option, even if it's just an inverter to run 110v occasionally. I was considering the Renogy 12V starter kit but read something about the controller being a limitation and I've seen a few opinions that two 6v batteries wired in a series will do me better than a single 12v.

    I'm very open as this is my first jump into solar, I know that I can run both of these off of a battery and just recharge the battery as needed because that is what I'm currently seeing other farmers do but I'd like to run this properly. I currently have a lot on my plate and that's why I'm reaching out for some help as I just cannot cover as much material as I'd like to in order for us to make an informed decision in the time frame that we need. Thanks in advance for any help, it will be very much appreciated.

    P

  • #2
    Welcome. So, the first thing is to really define the loads. If you under size the system, you run out of power and the greenhouse deflates. And the cordless drill won't charge.
    Oversize and you have lots of power, but spent more $ than needed.

    So, I'd suggest something like a 300W PV panel, a TriStar 30 Amp 12/24/48 Volt MPPT Charge Controller, a pair of 6V Golf cart batteries, and a Morningstar Suresine 300w inverter.
    1 large panel. simplifies wiring, a solid controller and inverter, and sturdy cheap batteries. You would have room to grow loads a bit.

    continue to use the generator to pump water, doing that with solar will get very expensive .
    Powerfab top of pole PV mount (2) | 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

    Comment


    • #3
      Mike, thanks for the quick response! We definitely plan on continuing to use the generator for pump and larger applications, I'm just looking for something quiet to run the day to day stuff.

      In all honesty, I was looking to spend a bit less, maybe half of what you proposed as an option. These are definitely quality products though and it's hard not to take the dive, knowing I could always use something like this to hook into our camper to save on some of our electric bill. With that said, I could hold out on the inverter for quite a bit so I guess my only questions and concerns revolve around the controller.

      Is there a reason to go with a 30 amp controller over a 45 amp controller in my application? The 45 amp is less than half the price of the 30 amp, and even the 60 amp is cheaper than the 30.

      Comment


      • #4
        Originally posted by pjp View Post
        Mike, thanks for the quick response! We definitely plan on continuing to use the generator for pump and larger applications, I'm just looking for something quiet to run the day to day stuff.

        In all honesty, I was looking to spend a bit less, maybe half of what you proposed as an option. These are definitely quality products though and it's hard not to take the dive, knowing I could always use something like this to hook into our camper to save on some of our electric bill. With that said, I could hold out on the inverter for quite a bit so I guess my only questions and concerns revolve around the controller.

        Is there a reason to go with a 30 amp controller over a 45 amp controller in my application? The 45 amp is less than half the price of the 30 amp, and even the 60 amp is cheaper than the 30.
        You are confusing the PWM controllers with the MPPT ones. With the PWM controllers you would need, for example, 12 volt panels to run a 12 volt battery bank. These 12 volt panels are costlier, per watt, than the larger grid type panels. MPPT controllers can take high voltage input and step down the voltage to your batteries needs. Running your array at high voltage has many benefits including simpler cheaper wiring and the ability to have your panels long distances (for optimum sun exposure) from your controller and batteries.
        2.2kw Suntech mono, Classic 200, NEW Trace SW4024

        Comment


        • #5
          There are 2 styles (ok 3) of charge controllers
          PWM (been around since Fred Flintstone, it's a fancy on-off relay, works fine)
          MPPT (newer design, does DC-DC power conversion, very efficient and allows saving of expensive copper wire on the PV array run)
          flea-bay MPPT ( take a $10 PWM controller and slap a 10 cent MPPT sticker over the PWM label, sell for $60)

          Be sure you are comparing prices of MPPT controller to MPPT controllers. Some implementations of MPPT are not well optimized and you miss out on some solar harvest.

          You can buy cheap, and replace it a couple times. Maybe that's best for you. A friend of mine just called last night, his controller fried itself, he broke his hand at work, and we have a week of heavy rain coming in, and he has no way to charge his batteries now. I'm going to help him get groceries up the hill tonight, his road will turn to mud by noon tomorrow.
          Powerfab top of pole PV mount (2) | 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

          Comment


          • #6
            Sorry for the mistake, I now realize that I was looking at the PWM from morningstar along side the same (in appearance) model. I was too focused on the amps to notice. Thanks for pointing that out! That definitely answers my question about the controller. I truly apologize, I'm sure you guys are rolling your eyes at this.

            Mike,
            We too have some crazy rain hitting us right now, about to hit 8 inches in the past 4 days, which is giving me a bit of time to figure this out. Hope your friend is alright!

            Comment

            Working...
            X