Announcement

Collapse
No announcement yet.

Question regarding replacing a small generator with solar/battery for a cabin

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

  • Question regarding replacing a small generator with solar/battery for a cabin

    Up front, I have very little knowledge about electrical systems general and solar in particular. I have an off grid log cabin, built last year, that the builder set up for use with a generator. I have a small (3500 w dual fuel Champion) generator that I use for basic things like a few lights, an overhead fan and charging the phone and laptop. There won't be any power hungry devices like an a/c unit, fridge or the like. I don't know the technical terms for what I have, but on the outside of the cabin there is a power inlet box with a cord and plug that I plug into the generator's 30 amp RV output plug, and inside the cabin there are about 5 receptacles for things to be plugged into. I hope I haven't screwed up the terminology too much...

    I'd like to have a solar system to power the cabin in addition to the generator (the generator is too dang loud, and I'm a bit of a trip away from the nearest propane station).

    I know I'll need a solar panel, deep cycle batteries and an inverter, but I have no idea whether that's all I'd need.

    In particular, can I use the batteries that are charged by the solar system to plug into the exiting power inlet and have it provide electricity through the existing receptacles?

    Again, sorry for any weird wording or missing information, and thanks for any help.

  • #2
    Welcome, and get your checkbook out !!
    Panels. Solar Charge Controller. Wires & J-boxes & Combiner boxes, Fuses or Circuit Breakers, Inverter. AC Transfer Switch. That would get you started.

    First step, what are your power needs. The more accurate your inventory and hours of usage, the closer you can dial in the amount of gear you need to buy, and not over buy. Adjusting the size of a system is difficult - like buying a mini-car and then next week finding out you need a full size van. More money.
    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
      Originally posted by Mike90250 View Post
      Welcome, and get your checkbook out !!
      Panels. Solar Charge Controller. Wires & J-boxes & Combiner boxes, Fuses or Circuit Breakers, Inverter. AC Transfer Switch. That would get you started.

      First step, what are your power needs. The more accurate your inventory and hours of usage, the closer you can dial in the amount of gear you need to buy, and not over buy. Adjusting the size of a system is difficult - like buying a mini-car and then next week finding out you need a full size van. More money.
      Thanks! This is a really basic cabin. I have a three lamps, each with a 60 watt bulb, that I use for a few hours after sundown and before sunrise, and an overhead fan that runs at 75 watts during the heat of the day. Beyond that, I'll recharge a cell phone and a laptop for an hour or two every day. That's everything I expect to have drawing power.

      Comment


      • #4
        With 3 x 60Watt used for say 2 hours that is 360 watt hours. The fan would consume another 300 watt hours running it for 4 hours. Add anything else and you start to get close to 1kWh a day or (night)

        Based on the latest prices of panels and batteries it will cost you about $1500 to $2000 to build a system that safely generates 1kWh a day. The good news is that 4 years ago that value was above $2500 so at least pricing is coming down but unless you have a very small load the cost of a generator and simple battery with a charger will be much less then getting into going with the entire solar/battery setup.

        Comment


        • #5
          I would add that you should do everything you can to reduce the load. For example, all lights should be LED. When you say you have 3x60watt lights, those should be replaced with LED bulbs. Once you do that and just run a laptop and cellphone, your load is really low.... probably <100watts.

          I had a similar setup for my offgrid cabin and had a generator, solar panel, batteries and a charger/inverter and it all worked really well. The trick is to keep you batteries charged up and not leave discharged for any length of time.

          btw - I think you are on the right track, I have neighbors near my cabin and they run a generator just to have a few lights on and charge their cellphone... it's crazy to be doing that.

          Comment


          • #6
            Originally posted by Remsen View Post
            I have a three lamps, each with a 60 watt bulb,
            Why on earth would you use 60 watt incandescent light bulbs for?

            MSEE, PE

            Comment


            • #7
              IF you are willing to buy another generator, a portable Honda EU2000i, or the like may better suit your needs. They are super quiet. I have a Champion 3500 and it is quite loud, but I need it for construction type field work.

              Also, depending on your needs a generator and battery bank combo might be a good way to go. Before my homestead got solar, the owner had an industrial generator (80 amps). As he ran that during the day, he also charged the battery bank for use at night.
              Last edited by citabria; 06-05-2018, 11:58 AM.

              Comment


              • #8
                Thanks to all for the responses. It sounds like I might be able to simply charge batteries as the generator is running for other purposes and then use the charged batteries later. There is a lot of appeal in this, but I'm still at a loss as to how I would connect the batteries to my cabin's power inlet box. I am pretty sure I have to have an inverter to get the DC power into AC form, but can I then just connect the inverter into the 30 Amp RV plug that I then plug into the power inlet box?

                Comment

                Working...
                X