Off grid from a NAWS kit: Suggestions?

biggerhammer
biggerhammer Registered Users Posts: 10 ✭
in Solar Beginners Corner #1
Hello. I'm sort of a newbie- I have lived on a teeny system for a year, but want to build a grown-up system now.
The old:
  • one 200w 24v panel
  • four T105 batteries
  • Missouri Wind and Solar 10KW PWM Charge Controller
  • Cheapo Chinese 2500 W modified sine inverter
  • almost sufficient wiring.
The prospective new system:
  • nine 250 watt panels
  • eight or sixteen L-16 batteries
  • NAWS prebuilt kit
  • Much better wiring.
I may add a 1600 watt wind turbine to this system.
What have I forgotten? What would be a better way to go?
This system is going to set me back about $12,000. I'm not going to be able to put much more money in this system for a few years (we will be saving money each month for eventual battery replacements).

Thank you for the advice.
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Comments

  • 2twisty
    2twisty Solar Expert Posts: 199 ✭✭✭
    #2
    Re: Off grid from a NAWS kit: Suggestions?

    What are your daily loads? That will be the first starting place to make recommendations.
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  • biggerhammer
    biggerhammer Registered Users Posts: 10 ✭
    #3
    Re: Off grid from a NAWS kit: Suggestions?

    Sorry, I mentioned that when I wrote this (then the internet ate it). My monthly consumption right now is 360 KWH. I'm planning to get rid of my top two consumers (ancient furnace and large fridge) so I expect our energy appetite to reduce significantly.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #4
    Re: Off grid from a NAWS kit: Suggestions?

    How will you be heating and cooking? Heating water?

    Likely I'd suggest forgetting everything you've been sold(or do I mean told?) Is your current panel a true 24 volt panel? with a vmp of around 35 volts? Most sold as 24 volt have a vmp of around 30volts, too low to charge a 24 volt system.

    Do you have alternate means of charging your battery. 200watts is very minimal to charge a 220ah 24 volt battery bank, though if your loads are minimal you might get away with it.

    9-250watt panels should provide about 35 amps of current on normal days to a 48 volt system, so around a single string of l-16's would be the most this would support in an active system, but as others have said, loads will determine the size system you need.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • biggerhammer
    biggerhammer Registered Users Posts: 10 ✭
    #5
    Re: Off grid from a NAWS kit: Suggestions?

    Heating, cooking and water heating are all propane.

    Our loads were minimal (one laptop, one mobile phone). We are increasing loads by moving a house on to the property, hence the upgrade.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #6
    Re: Off grid from a NAWS kit: Suggestions?

    I just don't see 11 kwh a day, with a furnace fan and fridge, and you're increasing loads with another home? or is this a replacement?

    West Texas is very good, should have lots of available sun most places.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • 2twisty
    2twisty Solar Expert Posts: 199 ✭✭✭
    #7
    Re: Off grid from a NAWS kit: Suggestions?

    Biggerhammer is a neighbor and good friend and I sent him here to get schooled....lol

    His "24v"panel is a standard Grid-tie 60-cell panel. I have not looked at the spec sticker, but I expect that it is as we expect.

    That said, we are building this new system totally from scratch. From NapkinQuickMath, we think that a system twice the size of mine will power all his loads apart from the furnace. And that's simply because the furnace fan is REALLY hungry. His current refigerator is an older, non-EnergyStar model (as is mine) and while they consume more power than EnergyStar models, they will run just fine.

    The usage data he quoted comes from his last power bill, which should be a fair idea of what his winter power use would be. The house also has a swamp cooler that will need to be rethought since it runs on a furnace fan, as well. So, we are speccing the system without those loads since he doesn't intend to run them as they are now. We will have to figure out a way to heat and cool the place, and perhaps we can find some fans that aren't so dang hungry. If not, we will find other ways to heat, either by space heating or by installing things like RV furnaces.

    NOTE: Where we live, we are not subject to any codes at all. The goal is to wire this system to NEC, but its not strictly required, nor will it be inspected.
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  • CDN_VT
    CDN_VT Solar Expert Posts: 492 ✭✭✭
    #8
    Re: Off grid from a NAWS kit: Suggestions?

    Place is huge ? mobile ? poor insulated & no sun roof ? think mini split ?
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  • 2twisty
    2twisty Solar Expert Posts: 199 ✭✭✭
    #9
    Re: Off grid from a NAWS kit: Suggestions?

    It's a 1950s-era mobile home. Single wide, full of leaks, etc.

    With the array that we're proposing, we can probably power the swamp cooler, since the time of day that we need the cooling most is also the time when we will have peak solar. The furnace fan, however, will be used most in the winter at night. If we could find a gas (propane) furnace that had a really low-power fan, then perhaps it could be run at night...but we'd like to find alternate options if we can't find the low-power option.

    I suppose a mini-split is possible, but since the place has multiple rooms, it could get really expensive. Since we're in the high desert, swamp coolers are VERY effective here. Rarely ever do we require AC.

    Hopefully Biggerhammer will see this soon and update the thread. I'll go poke him on facebook, but I think that he's making dinner at the moment.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #10
    Re: Off grid from a NAWS kit: Suggestions?

    I run a window air pretty much around the clock in the summer, off a 4kw array. I will likely add a mini split at some point to run when the battery is topped off, in the main living area. I heat with a woods stove, but my 'tin can' (mobile home) is a 2000 model 16x60 and in Missouri so likely less demand. Might look into replacing your fan in the furnace, or at least replacing the bearings.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • biggerhammer
    biggerhammer Registered Users Posts: 10 ✭
    #11
    Re: Off grid from a NAWS kit: Suggestions?

    1964 mobile home, 12x74 feet. Has one roof-mounted swamp cooler that would be nice to have, and as my Twisty friend points out, would be used mostly at peak solar hours.

    The furnace is original, huge, cranky and eats watts like there's no tomorrow. I plan to replace it with a propane wall heater (almost no electrical draw) and an RV furnace. The RV furnace will hook in to the existing underfloor ductwork to heat the two bedrooms; the rest of the trailer is open space so should all get enough heat from the wall heater.
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #12
    Re: Off grid from a NAWS kit: Suggestions?

    We unplug our fridge in the winter and use what cold mother nature provides. We then plug in our Toyo Laser 73 to heat 1,500sqft, when the woodstove can't be tended. In the winter we get no solar to help, so we charge daily with a genny. Around the end of February the Sun is back contributing.

    In My Opinion, If one is off-grid you should run from those mobile home furnaces, run fast and run far.

    TOYO http://toyoheat.com/
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