using array to power a couple things.

moyboy06
moyboy06 Registered Users Posts: 6 ✭
in General Solar Power Topics #1
I want to use a solar array in my field to just power like 1-2 devices for my farm. can i use an inverter and take the power straight from that to the device? For example, if I have a 1 kW array, can I take an on-grid inverter, and take the cables and tie them directly to power the device? Is that even practical/logical?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: using array to power a couple things.

    No. A grid-tie inverter requires the grid in order to function.

    The only way to power off grid is with an inverter that runs off batteries. Some grid-tie types have 'battery back-up' capability, but there is no point in paying for grid-tie if you can't use it.

    This means to get power you need:
    1). An inverter large enough to handle the total maximum load.
    2). Battery bank capable of supplying sufficient Amp/hrs to run the load over the time it will be used.
    3). Solar array able to produce sufficient charge rate to recharge the batteries.
    4). Charge controller to regulate the charge.
    5). Correctly sized wires, fuses/breakers et cetera to hook it all together.
    6). Enough sunlight to make it work all the time, or a back-up power source for when the sun doesn't shine.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: using array to power a couple things.

    MB06,

    Your question is a little confusing--do you have AC Grid to the point of use in the field and what a standard Grid Tied inverter? Or are the remote field points remote and have no grid connection?

    If you have grid at the location--yes, you can simply install a GT array+GT Inverter there... As long as you meet code and your utility lets you do this (and supports a reasonable billing plan).

    And--if you are grid tied--you need to define where the billing meter is (at the site or at a single common point at edge of the property).

    Placing the GT array remotely is not a requirement--it would work just as well anywhere on your property between the meter and the load--and may actually use "less copper" if mounted near the meter instead of remotely in the field (if the load is a constant 24 hour per day 2,000 watt load, and you want to offset 100% with GT solar--The solar array will generate most of its power ~5-6 hours per day--so it will peak at ~10,000 watts mid-day (and wiring to match back to the meter/utility drop) to average 2,000 watts of power 24 hours per day.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: using array to power a couple things.

    Bill -

    It sounded to me as though he was trying to "skip a step" and just go panel to GT inverter to device.
    Maybe not? :confused:
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: using array to power a couple things.

    Marc,

    :confused:

    MB06,

    In the end, what is the application... Water pumping to a holding tank (stock watering)... Solar panels and a pump (above ground or in ground) designed to operate from DC solar will be a good application.

    If the power usage requires power when the sun is not up--then an off-grid setup (panels, charge controllers, batteries, inverters) is required (and lots more expensive and maintenance requirements).

    Operating an AC inverter only from the Solar Array is more or less impractical. DC loads (like well pumps) will vary their pumping speed to meet the available power.

    AC loads require 100% of their power requirements. If the solar panel does not (morning/afternoon/clouds) meet 100% of the inverter's input power requirements--then the inverter's output power will shutdown.

    The battery is needed to meet surge/no sun power requirements for inverter/stable AC power usage (and adds lots of costs--very roughly 2x-4x as much cost with battery+inverter vs solar PV panels only).

    There are specialized applications where this may make sense--but there is nothing commercial where I can think of that this has been done.

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