Is this feasible?

Therealkoop
Therealkoop Registered Users Posts: 2
in Off Grid Solar & Battery Systems #1
Hello, new member. Been lurking for a while, and have always said "when I get a house I'm going to solar this and that". Well I bought my first home about 6 months ago and have been thinking about this since.

Anyway, My idea was a system to run a 220v 1/2hp 6amp well pump. That is about it, and the only thing I was really worried about. Is it feasible to make a system for around 3-4k to run this item? Other things I would like to run are perhaps a few simple light bulbs/12vdc charging units, and perhaps my furnace. The furnace looks to be 110v/1amp, and runs on gas.

I have already lost my power once, and lost water/hot water/heat as a result. It was out for 2 days due to the recent hurricane. Im mashing my brain with how many amp hours, charging rate, and what battery voltage to use, but as I'm learning id like to know if this is even feasible at this price point. If not I may just opt for a generator.

Thanks for any advice.
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Is this feasible?

    Solar is almost never cost effective as emergency backup power for a few days at a time... More or less, a full time off grid power system in a reasonably sunny part of the country will (very roughly) cost around $1 to $2+ per kWH when operated 9+ months of the year (assuming 20 year system life, 10 year electronics life, 5-10 year battery life).

    If you reduce the power used to only a few days a year--The cost becomes hugely more expensive.

    You can buy a generator (or two)--One small genset for the basic power (lights, fridge, sump pump, TV, computer, etc.)--something like a 1-2 kW Honda (or Yamaha) type inverter-generator and store 10-20 gallons of fuel (with stabilizer+recycle to car once a year)--And perhaps a "cheap" 3.5-5kW genset to power your well pump a couple times a day (plus any shop tools, etc.). That will last you 5-10 days or so pretty easily.

    Otherwise, you could make a "small" solar power system to power your lights+computer+heater and use a genset for well pump/bad weather.

    To size a system... Need to know how many watts * how many hours. Say you need 100 watts * 10 hours per day, that is 1,000 Watt*Hours (or 1 kWH).

    Then we just size the battery bank, solar panels, backup generator from there.

    A Kill-a-Watt type meter is handy for the smaller loads (15 amp @ 120 VAC plug-in loads).

    Given that batteries age out whether they are used or just float charged--It makes it very difficult to justify usage as a purely emergency power system that is only used a few days a year. Unless your power is very unreliable or you have critical loads (fridge with medicines, HAM/CERT emergency comm gear, etc.) that need 24x7 power.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Therealkoop
    Therealkoop Registered Users Posts: 2
    #3
    Re: Is this feasible?

    Thanks for the insight. Perhaps Ill just make a small setup for the hobby aspect. Charging ipods and whatever else.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
    Re: Is this feasible?

    being on the grid means you won't need to selectively power something with solar as a gt system can offset the power used. now a generator can also fill in the gaps of small outages. as an option one could go with a battery backed gt system. this won't necessarily last longer than a generator, but is great for a fast and reliable unattended switchover.
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