Pole barn tie-in to feed house?

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Brewgonia
Brewgonia Solar Expert Posts: 31 ✭
in Solar Beginners Corner #1
I have 100amp service run from the main house to the pole barn. If my battery bank is either in the pole barn or in a small shed next to it, can I tie it into the pole barn service and still expect to draw energy from the batteries in the main house?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Pole barn tie-in to feed house?
    Brewgonia wrote: »
    I have 100amp service run from the main house to the pole barn. If my battery bank is either in the pole barn or in a small shed next to it, can I tie it into the pole barn service and still expect to draw energy from the batteries in the main house?

    Welcome to the forum.

    Your question is somewhat ambiguous. The battery bank is where? And do you want to try and run DC power from there to somewhere else? That probably won't work due to the Voltage drop over distance.

    But if you have a battery bank and inverter at one location and want to run 120/240 VAC from there to the other location it is possible.
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  • Brewgonia
    Brewgonia Solar Expert Posts: 31 ✭
    #3
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    Re: Pole barn tie-in to feed house?

    Attachment not found.
    Cariboocoot wrote: »
    Welcome to the forum.

    Your question is somewhat ambiguous. The battery bank is where? And do you want to try and run DC power from there to somewhere else? That probably won't work due to the Voltage drop over distance.

    But if you have a battery bank and inverter at one location and want to run 120/240 VAC from there to the other location it is possible.

    I'll try to attach a diagram. If battery bank is located in position A in the Pole Barn, and the inverter feeds the 100A panel in the barn which is fed through 3AWG wires from the house main 200A panel, will the house be able to get any useable power or will the voltage drop over the 3AWG wires drop too much? Those wires are probably 100'.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
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    Re: Pole barn tie-in to feed house?

    So what we're looking at is the question of how much power loss will there be over 100' of 3 AWG wire at 120 Volts or 240 Volts? Is the wire by any chance aluminium?

    Let's try 120 VAC and copper: over 100' of 3 AWG 100 Amps of current results in a V-drop of just over 3% which is well within tolerance. On 240 VAC it's even less of a problem. Aluminium wire would be half as good.
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  • Brewgonia
    Brewgonia Solar Expert Posts: 31 ✭
    #5
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    Re: Pole barn tie-in to feed house?
    Cariboocoot wrote: »
    So what we're looking at is the question of how much power loss will there be over 100' of 3 AWG wire at 120 Volts or 240 Volts? Is the wire by any chance aluminium?

    Let's try 120 VAC and copper: over 100' of 3 AWG 100 Amps of current results in a V-drop of just over 3% which is well within tolerance. On 240 VAC it's even less of a problem. Aluminium wire would be half as good.

    The wire is copper and 3% is certainly acceptable.

    I don't know if I'll be going the 120VAC or 240VAC route yet.

    One option is to have the battery bank in the shed at position B. That would be approximately 12' from the panel in the pole barn. Is that acceptable? I assume to make it possible the wire would need to be pretty thick stuff.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
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    Re: Pole barn tie-in to feed house?

    Another 12 feet isn't going to make much difference against 100 feet.
    You do realize that 100 Amps @ 120 Volts is far more power than any inverter is going to put out, don't you? That's 12kW. It would take two XW 6048's to produce that kind of power, and then that would be @ 240 VAC so it would be even more power. Twice as much in fact.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #7
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    Re: Pole barn tie-in to feed house?
    Brewgonia wrote: »
    the inverter feeds the 100A panel in the barn which is fed through 3AWG wires from the house main 200A panel

    What is the purpose of this system? I ask because you need to buy one or more inverters, and there are many different types. Will there be solar?

    When the grid goes down what happens? Does the battery/inverter system take over automatically? How fast a transfer do you need? You may need transfer switches at each end of the line, and these switches will have to be controlled by something. You may need to run some control and monitoring cables between the house and barn. There may be some interesting issues with a transfer switch and neutral-ground bonding.
    Is there a ground rod at the 100A panel in the barn?

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • n4wff
    n4wff Solar Expert Posts: 48 ✭✭
    #8
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    Re: Pole barn tie-in to feed house?

    I have all my solar and batteries in the barn. This is a diagram of how I have my system set up.

    Attachment not found.

    The meter and manual transfer switch is on the house. The inverter and batteries are in the barn. I have aluminum 2-2-4 urd feeding my barn from the grid and back to the house. From the inverter output, I have a line run from the barn back to the house to the transfer switch. The reason I did it this way is occasionally my loads in the house will run more than the XW can handle. With the transfer switch, I tie the house directly to the grid. The inverter on the other hand feeds back through the meter and shaves the load, so I still get the benefits of selling back to the power company. When we lose power, all I have to do is flip the transfer switch, and I get the power from the inverter. I just have to watch my loads.
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  • Brewgonia
    Brewgonia Solar Expert Posts: 31 ✭
    #9
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    Re: Pole barn tie-in to feed house?

    The system has two purposes:

    1) provide minimal life support to house when grid goes down, which it does equally in summer and winter here in northwest Indiana. By "minimal" I mean run the furnace; then in order or most importance to least fridge, freezer, well pump (we are on well/septic), cable modem/WAP (gotta keep the wife and kid happy), TV and satellite box, game system, some lights. It doesn't get Arizona hot here in the summer so running the A/C instead of the furnace is something I want to consider - but it may or may not be a priority.

    By experience the grid has been down anywhere from 4 hours to 5 days. Ideally I would like 24-48 hours worth of battery storage and take my chances that I can recharge as we go.

    How would I recharge? Being that we get a mix of sun and wind, but neither in tremendous quantities I am set on a combination PV and wind turbine setup. I also have a small Yamaha 2400is generator that I could use to recharge batteries or individually power devices if it comes down to that.

    The 100A panel in the barn does have its own ground rod.

    I am just learning about all this - the theory, application , maintenance, so I can't say yet what the total load will be, how many inverters, how quick it comes on, etc. I am not sure yet about doing grid-tie but if I do, I certainly want it to be safe but not necessarily automatic.

    2) the second goal would be to power the lights in the pole barn. It's used infrequently for anywhere from an hour a day to 6 hours. There are six flourescent fixtures each with two 110 watt bulbs.
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  • Brewgonia
    Brewgonia Solar Expert Posts: 31 ✭
    #10
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    Re: Pole barn tie-in to feed house?

    N4wff,

    Thanks for the diagram and explanation. Are you powering your entire house or do you have select circuits? Also, how long do you get off the 930Ah of battery?

    Len
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  • n4wff
    n4wff Solar Expert Posts: 48 ✭✭
    #11
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    Re: Pole barn tie-in to feed house?

    The inverter is wired to the whole house, but it will not power everything at once. I manually have to check and make sure not to run several big loads at one time. As far as the batteries, I need to clarify. They started life at 930ah, but are nowhere near that capacity now. If I keep my loads light, they will make it through the night. After pricing a new set of batteries, I believe I can limp along with these for a while. Others have posted that it is better to have a set of cheap batteries until you can tweak the system to work out all the bugs. I paid scrap lead prices for the batteries, so I am out nothing when I decide to replace them.
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