Not understanding calculations

Paul
Paul Registered Users Posts: 1
in Solar Beginners Corner #1
I am new to this whole solar power thing and can't quite figure it out. I want to start out small first. I live on a farm and recently put in a pond. To far from a power source, so I planned on solar power for my aerator. My question is, I have a 110v, 5amp pump. I was looking at a 175amp solar panel so I could run the pump only while the sun was up and therefor would not need the batteries. When I contacted the supplier, he told me I would 1400watts to operate as I wanted. Why? Is he trying to sell me more than I need or are his calculations correct?
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  • froggersix
    froggersix Solar Expert Posts: 35 ✭
    #2
    well panel is dc and pump is ac so it won't work directly without batteries and inverter anyway but otherwise 110 volts and 5 amps is 550 watts so 175 watt panel wouldn't make enough power anyway.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
    Hi Paul, welcome to the forum.

    With what little information provided, it's really impossible to answer at this time. We don't know the make and model (thus the specs) of the pump you have - - will it operate on a wide range of voltages, is it run by an AC motor, or a DC motor, is it a special slow start, no surge motor, or a standard off the shelf motor etc.
    Re your "175 amp" solar panel, do you by chance mean it is a 175 WATT panel? What is the Max Power Point voltage of that panel?
    Either way, this isn't going to be a cheap or small system and a 175 watt panel (if that's what it is) is VERY unlikely to come anywhere close to running your pump.
    More information needed.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,590 admin
    #4
    And how far is the pond from a utility power source? If it is hundreds of feet, probably worth running 120/240 VAC to the pond. If much farther, perhaps solar is possible.

    In general, need to get the most efficient pump/air mixing system you can, then look at sizing the solar system to power it.

    If you can live with using solar power only during the day/sunny weather, then looking at a system that does not use a battery bank can save you lots of money/maintenance costs (a battery based solar power system probably costs 4x that of a straight solar panels to pump motor type system).

    The problem with anything that moves water/air/etc... These things use a lot of power--And Off Grid solar (+battery bank + AC inverter + Charge controller + etc.) usually costs something in the $1-$2+ per kWH--Or roughly 10x the cost of utility power.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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