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What size solar for well pump?

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  • Decidion
    replied
    Originally posted by Naptown View Post
    It's not quite that bad
    ...
    Now for the generator
    About 10K installed
    .85 gallons of propane per day x365 = 310gallons per year.
    Propane here is about $3.00 per gallon so $950 per year in fuel costs.
    figure 6-7 oil changes per yer in there at ?
    With oil changes figured at $20 each and not counting other breakdowns in the generator let's look at life cycle costs over 20 years.
    Total install and operating over 20 years $31,400
    ...
    I see where you are going with this, but it's not quite that bad with the propane genny either. Propane is only $2.20/gallon here and the maintenance interval on the genny is 500 hours. So the cost for the generator is probably closer to $20K. But that is still double what you came up with for solar costs.

    I'm kind of thinking out loud here...but our house is 300' from the well. How far could I run a line that was pushing 110-120v before the loss was impractical or the size of the cable too expensive to justify?

    Leave a comment:


  • Naptown
    replied
    It's not quite that bad
    Panels about 3500
    Racking (roof mount flush) 600
    Charge controller about 600
    Batteries 800?
    Inverter about 1000
    Total about 6500.00
    Fuel costs 0

    Now for the generator
    About 10K installed
    .85 gallons of propane per day x365 = 310gallons per year.
    Propane here is about $3.00 per gallon so $950 per year in fuel costs.
    figure 6-7 oil changes per yer in there at ?
    With oil changes figured at $20 each and not counting other breakdowns in the generator let's look at life cycle costs over 20 years.
    Total install and operating over 20 years $31,400

    Solar 6500
    If you buy good batteries you should be able to get 5 years out of them.
    So over 20 years $3200
    Inverter and charge controller will probably die and need to be replaced.

    Solar initial investment 6500
    Less 30% federal credit 1950
    Net solar cost 4550
    Battery replacement 4x 800 = 3200
    Inverter and charge controller replacement 1600
    Total install and operating over 20 years. $9350

    The numbers are based on a diy install using UL listed components.
    Last edited by Naptown; 01-23-2012, 04:57 PM.

    Leave a comment:


  • russ
    replied
    NE Washington is one of the better locations for sun! NW Washington doesn't get enough sun for much of anything but you are better off - if a bit colder

    The cost may be more like 5$ per DC watt

    Look at solar hot water heating or air heating if you want a solar project with better efficiency/return.

    Leave a comment:


  • Decidion
    replied
    Wow, at the US Dept of Energy avg of $8 - $10 per watt, that comes to about $18,000 just to run my well pump. I'm just shocked that it would cost that much.

    If I bought a 1000 gallon propane tank + 800 gallons of propane to fill it = $6500 (roughly)
    6Kw propane generator + installation = $3500 (roughly)

    So about $10,000 total.

    I would only need to run the pump about an hour a day (at 4 gallons of water per minute). The generator consumes .85 gal/hour at 50% load, so if I only used it for the well, I could run that well pump for over 20 years for a little more than half of what it would cost to run it on solar (assuming the batteries lasted 20 years, which I don' think they would).

    After everything I have been finding out about solar power, at least for the area I am in (NE Washington state), I don't ever see a break even point (much less getting ahead). This is depressing.

    Leave a comment:


  • Sunking
    replied
    Based on your specification:

    Panel wattage = 2000 watts
    Charge Controller = MPPT 80 amps
    24 Volt Battery Capacity = 300 AH AGM type
    Inverter = 3000 Watt True Sine Wave

    Leave a comment:


  • Decidion
    started a topic What size solar for well pump?

    What size solar for well pump?

    I have a Grundfos 5SQ-180 that is sitting 250' down a 260' well that has a static water level of 30' (so lots of water sitting down that hole). The replenish rate of the well is only about 2 gpm, but I just pump it to the surface into water storage containers (55 gallon food grade barrels) for now.

    For the last year since I have had the well drilled, my little Honda EU2000i has worked admirably (on gas, won't run the pump on propane though), but I really want to get a solar system set up to run the pump.

    I know the Grundfos is a 1/2 hp motor and the pump pulls about 12amps @ 115v.

    With this in mind, I believe i need a 1500 watt inverter (and I can only seem to find modified sine wave inverters below 2000 watts), but what size battery bank would I need to run the pump for say an hour before I was at 50% DOD?

    And how many watts in solar panels would I need if my winter peak sun hours is 1.5? I know I'll also need a charge controller....but am I missing anything else?

    Would a system like this function when it was 10 degrees Fahrenheit out?

    Thanks
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