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Switching one array between two different buildings/setups.

longcreekridge

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Joined
Jan 16, 2024
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27
Location
Central VA
I've run multiple searches and haven't found any threads addressing this exact idea, which may suggest it is entirely unfeasible, but it could also suggest my situation is unique. Appreciate any and all input offered.

I look after a remote ancestral homestead owned by an extended family. No one lives there full time, but people visit at various times. It is grid tied, but no one likes paying for an extra power bill and there is a big imbalance in who uses it when, so I am trying to get it to a place where it is self sustaining, especially during any extended outages. Power bills are currently low (we shut off everything but the fridge between uses), so I understand pay-off calculations won't necessarily make sense in the short term. The long-term goal is more conceptual self-sufficiency than saving money in the short term, if that makes sense. That being said, I've spent a good chunk already and want to use that system as efficiently as possible.

The first phase of the project was to get a workshop powered that will serve as homebase for a long term renovation of the house. This phase is more or less complete, with 4000w of panels feeding a 6000xp and a powerpro battery. So far, this provides all the power I need and then some. When I am not there, the battery drops to 90% overnight from inverter draw, then tops off by noon every day. I need the overhead for when I am there and using all my tools and lights, etc. all day, but I really want to make use of the power I am generating when not there and the house is the place where power is needed, especially in an emergency when the shop can be shuttered.

In short, I would like to use one array to feed two different buildings, each with their own setup, depending on the need and who is there. While I'm there, the array would feed the workshop setup. While I am not, or when someone else is there, it would feed the house. I understand this could be achieved using 2 DC breakers as a switch for the array, but as someone fairly new to solar I am curious what pitfalls or problems this might introduce. For clarity, the buildings are far enough apart (approximately 100 feet) and have enough individual power needs that it doesn't make sense to use one inverter/battery setup to power both.

Does anyone else do anything like this?
Are there reasons why this makes no sense?

Thank you.
 
Last edited:
... For clarity, the buildings are far enough apart (approximately 100 feet) and have enough individual power needs that it doesn't make sense to use one inverter/battery setup to power both.
....
Why not run wire from the workshop to the house to provide AC to it? Certainly cheaper than trying to use one array with 2 separate inverter battery setups. It actually does make sense if the buildings are only occasionally occupied. If the 6000XP is insufficient adding another one to the setup is easier if next to the old one and the battery bank is common.
 
Why not run wire from the workshop to the house to provide AC to it? Certainly cheaper than trying to use one array with 2 separate inverter battery setups. It actually does make sense if the buildings are only occasionally occupied. If the 6000XP is insufficient adding another one to the setup is easier if next to the old one and the battery bank is common.
I agree. Feed the house ac from the workshop. Have enough battery and inverter to run what is needed. Keep is simple.
 
Why not run wire from the workshop to the house to provide AC to it? Certainly cheaper than trying to use one array with 2 separate inverter battery setups. It actually does make sense if the buildings are only occasionally occupied. If the 6000XP is insufficient adding another one to the setup is easier if next to the old one and the battery bank is comm

That was the initial plan but I got hung up on the specifics, and how many circuits I could feasibly run that way. Also, house needs (well pump, hot water heater, oven, etc.) are much higher wattage than the shop. My panel in the shop is 100A. Would I use a large breaker in the shop > 2-2-2-4 > to another subpanel in the house?
 
That was the initial plan but I got hung up on the specifics, and how many circuits I could feasibly run that way. Also, house needs (well pump, hot water heater, oven, etc.) are much higher wattage than the shop. My panel in the shop is 100A. Would I use a large breaker in the shop > 2-2-2-4 > to another subpanel in the house?
It is really not about the number of circuits but which loads and how many at 1 time. For instance your water heater if electric is likely 4500W. A inverter sized to only run this would mean you would need to not run other things at the same time. But water heats up in a hour or two and than the inverter is free to power other things. Smaller the power supply the more load management is needed.

Your panel of 100A could in theory provide loads up to 24,000W. But your supply of 6000W (inverter) could not.
 
O
It is really not about the number of circuits but which loads and how many at 1 time. For instance your water heater if electric is likely 4500W. A inverter sized to only run this would mean you would need to not run other things at the same time. But water heats up in a hour or two and than the inverter is free to power other things. Smaller the power supply the more load management is needed.

Your panel of 100A could in theory provide loads up to 24,000W. But your supply of 6000W (inverter) could not.
Thanks much for the follow-up. This gives me a lot of food for thought. Given the existing 200A, grid-tied panel in the house, I suppose it would only make sense to move some of the critical loads to a second off-grid, shop-fed panel (especially if I want to avoid the hassles of permits and inspectors).
 
O

Thanks much for the follow-up. This gives me a lot of food for thought. Given the existing 200A, grid-tied panel in the house, I suppose it would only make sense to move some of the critical loads to a second off-grid, shop-fed panel (especially if I want to avoid the hassles of permits and inspectors).
That is one approach. But you could also use a breaker interlock setup or a transfer switch if powering the main panel would work for you.
 

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