I need help for a Small system for a solar dummy.

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  • SunEagle
    replied
    Originally posted by Wy_White_Wolf

    The wattage of the array does not change with battery voltage. It needs to be 1000 watts with either 12 or 24 vdc.

    WWW
    Oops. You are correct. Thanks for checking my math.

    Leave a comment:


  • Wy_White_Wolf
    replied
    Originally posted by SunEagle

    Well that freezer is going to draw about 200 watts (115v x 1.7amp = 196watts). But not continuously. So lets say it runs 10 hours a day at that load. That calculates to 2kWh.

    I am still not sure what that fan draws but lets say you are correct and it is .6kWh/day or ~600wh.

    Now add that 600wh to the 2000wh and you have two loads at about 2.6kWh a day.

    To size your battery system, you need one that can delivery ~ 2600wh x 4 = 10400wh.

    A 12volt battery system would have to be 10400wh / 12v = 870Ah.
    A 24volt battery system would be about 10400wh / 24v = 435Ah

    Depending on where you live you will need an 80A MPPT and about 1000 watts of panels for a 12volt battery. And about 1/2 that 40A MPPT and 500 watts for a 24v battery system.

    Now that does not include any wiring, framework, inverter, fuses, etc. So go check out the prices of that battery system and lets us know if it would be cheaper than running a 110v AC line?
    The wattage of the array does not change with battery voltage. It needs to be 1000 watts with either 12 or 24 vdc.

    WWW

    Leave a comment:


  • Sunking
    replied
    Originally posted by Janachovsky
    Got ya, so in series would need 2- 12v @ 450ah
    No such thing as a 12 volt 450 AH battery. You are stuck inside a 12 volt Toy Box. Batteries are 2-volts. If you need 24 volts @ 450 AH, you buy 4 x 6-volt 450 AH batteries and wire them in series. Never Ever parallel batteries unless absolutely necessary, and rarely ever necessary unless you need more than 4000 AH. Large batteries come in 2, 4, and 6 volts. Get out of the 12 volt box.

    FWIW if a 12 volt 450 AH battery existed, and there maybe some made for railroads, would weigh 300 or more pounds. Even a 6-volt 450 AH battery has some weight of 150 to 160 pounds.
    Last edited by Sunking; 04-09-2017, 10:57 PM.

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  • SunEagle
    replied
    Originally posted by Janachovsky
    Got ya, so in series would need 2- 12v @ 450ah

    ​​​​​
    The problem is finding (or even moving) a 12volt 450Ah battery. They would be very heavy even if you could find them.

    The only way to build a 12v 450Ah battery system would be to use 6 x 2v 450Ah batteries wired in series.

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  • Janachovsky
    replied
    And in parallel would need 2- 24 volt batteries at 225ah?

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  • Janachovsky
    replied
    Got ya, so in series would need 2- 12v @ 450ah

    ​​​​​

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  • Mike90250
    replied
    incorrect. Batteries in series adds VOLTAGE Parallel adds AMPS 2, 12v batteries at 225ah in series = 24v 225ah

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  • Janachovsky
    replied
    I can get 2-12v batteries at 225ah in series to make 24v 450ah correct?

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  • Sunking
    replied
    Originally posted by Janachovsky
    Yeah it probably is, but it can't b that expensive for a fan running all the time that uses .6kwh/day and a 115v 1.7amp chest freezer with externally controlled thermostat so I can use it as a fridge. Can it?
    Yes 5 to 10 times more expensive. If you can use commercial power, do so. You should not take anything off-grid if other options are available and nothing is less expensive and reliable than commercial AC power.

    Its the batteries and system efficiency that bites you in the butt and no way around it. Just in battery cost alone is what drives it to 5 to 10 times more expensive. If Sun Eagles guess is correct, and he is close at 2 Kwh per day is 20 to 30-cents/day, $6 to $8/month, $72 to $96/year and in 4 years of a good battery life $288 to $384. A good 4 year battery will weigh 600 pounds and cost you $1500 to $2000.

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  • PNPmacnab
    replied
    I run a 7CF chest fridge and it takes me a KW of panels to do it and my system is far smarter than anything that can be dreamed up here. Where are you that 4.5 hours of sun per day is what you estimate? Usually people are overestimating sun.

    Leave a comment:


  • SunEagle
    replied
    Originally posted by Janachovsky
    Yeah it probably is, but it can't b that expensive for a fan running all the time that uses .6kwh/day and a 115v 1.7amp chest freezer with externally controlled thermostat so I can use it as a fridge. Can it? I'm having a hard time calculating what I need, and just keep confusing myself more thoroughly.
    Well that freezer is going to draw about 200 watts (115v x 1.7amp = 196watts). But not continuously. So lets say it runs 10 hours a day at that load. That calculates to 2kWh.

    I am still not sure what that fan draws but lets say you are correct and it is .6kWh/day or ~600wh.

    Now add that 600wh to the 2000wh and you have two loads at about 2.6kWh a day.

    To size your battery system, you need one that can delivery ~ 2600wh x 4 = 10400wh.

    A 12volt battery system would have to be 10400wh / 12v = 870Ah.
    A 24volt battery system would be about 10400wh / 24v = 435Ah

    Depending on where you live you will need an 80A MPPT and about 1000 watts of panels for a 12volt battery. And about 1/2 that 40A MPPT and 500 watts for a 24v battery system.

    Now that does not include any wiring, framework, inverter, fuses, etc. So go check out the prices of that battery system and lets us know if it would be cheaper than running a 110v AC line?

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by Janachovsky
    Yeah it probably is, but it can't b that expensive for a fan running all the time that uses .6kwh/day and a 115v 1.7amp chest freezer with externally controlled thermostat so I can use it as a fridge. Can it? I'm having a hard time calculating what I need, and just keep confusing myself more thoroughly.
    Suit yourself, but yes, it can be a PITA and cost a lot of money relative to other ways of accomplishing the required tasks, especially if grid power in available. I'd run a 110 V AC line or maybe even an extension cord if not too far a distance and call it done until you learn more about solar and PV, especially if you are a solar neophyte. Hobby is one thing, a lot of fun and a good learning experience. Thinking you'll save money before you know what's involved is another.

    Leave a comment:


  • Janachovsky
    replied
    Yeah it probably is, but it can't b that expensive for a fan running all the time that uses .6kwh/day and a 115v 1.7amp chest freezer with externally controlled thermostat so I can use it as a fridge. Can it? I'm having a hard time calculating what I need, and just keep confusing myself more thoroughly.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by Janachovsky
    Not sure what u mean by 120v line to the hopper? U mean just regular grid power?
    Yes. If that's possible, it may well be cheaper and more reliable w/a lot less hassle. Just sayin'.

    Leave a comment:


  • Janachovsky
    replied
    Not sure what u mean by 120v line to the hopper? U mean just regular grid power?

    Leave a comment:

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