off grid system advice?

[Sabre36]

So the property in question is on about 300 acres in Northwest Maine. The house is currently wired for 240V but power was never brought into the structure due to the 2/3 mile long driveway and the cost CMP used to charge to run a private line.

We have decided to do an off grid system rather than spend the $36,000 to bring power into the house. We have power to the barn but, the barn is over 1/8 of a mile away from the house.We do plan to trench to the house and run 120 V to the battery area in the house to run chargers should the solar system fail. the room for the batteries will be in a 10 foot deep basement. The room will be full spray foam insulated &will not be a big room. It will have its own propane heater that will come on should temperature get low enough. We plan to use a server rack batteries most likely. I already kiled a Winston cell bank running a cold weather experiment.

thinking about using 10 or so Q cell 360 W panels & a victron Quattro inverter and leaving the house 120V?

looking for advice on reasonably priced ground mount solar rack solar rack?

have not yet decided on battery voltage but I have spools of 4/0 marine wire so that's not an issue

the solar rack will be quite a ways from the house so I want to run the the array at a fairly high-voltage to minimize the wire diameter coming into the house

any tips on this would be very appreciated

I

 

[Rednecktek]

Well, I'll start the default answer to these questions and we can work from there. Here's you To-Do list:

1: Power audit! This will give you some important information on how big your inverter needs to be as well as how much battery capacity you'll need. There is a link in the FAQ section (I think, or someone here will post it shortly) so fill in the blanks and see what it comes up with. You'll probably need some sort of Kill-A-Watt to get accurate measurements. Are you going to be running a 12v system? 24v system? 48v system? What are the specs on your solar panels? VoC? Vmp? Being as this is a new build, throw together a wish list of what you want and estimate on the high side.

1a: Where do you live? Speccing out a system for Scotland is a LOT different numbers than Arizona due to the amount of light you actually get. Someone here can post the link to the PVwatts.com or JCR Solar Uber-Sun-Hours calculator sites to help figure out how much you'll have to work with. That will be a box in the Power Audit form.

2: Parts list: You don't need a make & model list, just a parts list to start from for reference. You'll need an inverter, a MPPT charge controller, fuses, shunt, buck converter, batteries, wire, etc. Once you have a basic list it can be fine tuned to make & models after that. If you're looking at the All-In-Ones check for correct voltage outputs (120v or 240v Split Phase for North America, 220v Single Phase for European type areas) and make sure it has enough capacity for a little bit of growth and fudge factor.

3: Budget!: Steak is great but doesn't mean anything if your wallet says hamburger. Figure out what you're able to spend now vs what you'll have to cheap out on now and upgrade later.

4: Tape measure! Figure out where you're going to stick all the stuff you'll need. A dozen 3000AH batteries sounds great until you're sleeping on the floor because there's no room left for a bed. Is there a compartment that can house all this stuff? Will the server rack batteries fit? Are you going to have to make space? Physics can be pretty unforgiving.

5: Pencil out what you think you need and throw it at us so we can tell you what you've missed (because we ALL miss stuff the first go-round ) and help figure out which parts and pieces you're going to want to get.

 

[12VoltInstalls]

any tips on this would be very appreciated

300 acres in Northwest Maine. The house is currently wired for 240V but power was never brought into the structure due to the 2/3 mile long driveway and the cost CMP used to charge to run a private line.

You’ll want a split phase system to use your (likely) 200A panel to its fullest.

We have power to the barn but, the barn is over 1/8 of a mile away from the house.We do plan to trench to the house and run 120 V to the battery

So 600’. Why not power from the barn? That’s only 600’ not 3500’ and if you’re digging a trench already…

using 10 or so Q cell 360 W panels & a victron Quattro inverter and leaving the house 120V?

3600W input? What are planning on running? I’m in Vermont. This year was a poor late winter and spring for solar. Many days on end of very low solar or no solar input. Maine will be similar. November to March is tough anyways in the northeast. There’s a lot to be considered.

10 or so Q cell 360 W panels & a victron Quattro inverter and leaving the house 120V?

The house is already 120V- just the 240V feeds two sides of your panel 120V each. I’d get a split phase inverter or aio.

But what is going to work? No way to tell without knowing your equipment. Or how many kWh of batteries.

looking for advice on reasonably priced ground mount solar rack solar rack?

Manufacturing Dependency Syndrome
Build a robust ground mount array with pressure treated lumber. Plan for more panels; in winter you’ll want three times what you need and you may wish to go vertical in winter so snow and ice don’t accumulate which shaves some more potential harvest in a tough time of year.

 

[Sabre36]

You’ll want a split phase system to use your (likely) 200A panel to its fullest.

So 600’. Why not power from the barn? That’s only 600’ not 3500’ and if you’re digging a trench already…

because the minute we go grid tied underground power we are going to need to follow code which means about 30k in expenses
We also lose our of-grid tax status and our property taxes will go from about $1680/year to approx $16k! We own a excavator which is capable of digging a trench for some 6 AWG just to power emergency back up chargers.Because the main panel would not be fed from the grid we could retain our of-grid status.

3600W input? What are planning on running? I’m in Vermont. This year was a poor late winter and spring for solar. Many days on end of very low solar or no solar input. Maine will be similar. November to March is tough anyways in the northeast. There’s a lot to be considered.

lighting, standard household appliances. well, and a heating system.We are working on calculating energy use . We want a big enough array an bank to run the house for multiple days.Budget is not a huge deal we just want to do it right.

 

[12VoltInstalls]

lighting, standard household appliances. well, and a heating system

Do the energy audit.
My wildhat guess says 3600W ain’t gonna be happiness in paradise. Another wildhat guess is that 3600W of panels might do ok for some city type appliances and lifestyle stuff in the summer. If being gridtie would make your taxes $16K I’m thinking you’ve got a way lot of house stuff to power.

the minute we go grid tied underground power we are going to need to follow code which means about 30k in expenses

You should follow code anyway. The code is there filtering down from NFPA and it saves lives. Conduit would be like what? $3500, and a proper subpanel and the right cable shouldn’t probably be negotiable expenses.

 

[Checkthisout]

because the minute we go grid tied underground power we are going to need to follow code which means about 30k in expenses
We also lose our of-grid tax status and our property taxes will go from about $1680/year to approx $16k! We own a excavator which is capable of digging a trench for some 6 AWG just to power emergency back up chargers.Because the main panel would not be fed from the grid we could retain our of-grid status.


lighting, standard household appliances. well, and a heating system.We are working on calculating energy use . We want a big enough array an bank to run the house for multiple days.Budget is not a huge deal we just want to do it right.

Charge controllers and stuff are easy.

If you have power on site but you don't think it's enough, then just have them power a couple of large victron multipluses and nice lithium battery bank.

Treat your batteries as a cistern for your low flow power situation instead of farting around with panels and charge controllers.

 

[Sabre36]

Do the energy audit.
My wildhat guess says 3600W ain’t gonna be happiness in paradise. Another wildhat guess is that 3600W of panels might do ok for some city type appliances and lifestyle stuff in the summer. If being gridtie would make your taxes $16K I’m thinking you’ve got a way lot of house stuff to power.

The house is not huge, a ski chalet style, but ,as it is now the town has it clasified as off-grid which basically means woodlands and some outbuildings. The minute we conect to the grid it gets treated as if it is some palatial estate on 300 private acres. As long as it remains off grid the taxes don't change. This is why we only brought power into the barn.

You should follow code anyway. The code is there filtering down from NFPA and it saves lives. Conduit would be like what? $3500, and a proper subpanel and the right cable shouldn’t probably be negotiable expenses.

We are following code but here in Maine for underground power we would need an aditional pad mount transformer and service risers ever so many feet (yes, even on private property)we also would be forced to bring in phone cable and fiber. Due to storms there is no way we would run it above ground.This sends the cost through the roof. Much cheaper to treat the house like an outbuilding off the barn, this is legal, and run enough power to charge the batteries. if needed.

 

[WYtreasure]

I like the "leaving the house at 120V" idea. Nice & simple.
Building your array out of lumber sounds good to me, if you are a builder kinda guy or have neighborhood help. Lumber is a renewable resource and might not come off a ship.
Connect your charging wire, in the barn, with a biggass plug so you are not too close to the "on grid" classification. You can say "It's just a really long extension cord." ?

 

[LazyDragon]

As others have said, a big piece of the puzzle is your expected usage. Do you have gas or propane? Your big electric power consumers are home heating, water pumping/pressurizing, water heating, clothes dryer and stove. If those are gas, your electric needs will be easy to solve. The more of the big boys you move from gas to electric, the bigger your challenges.
Since you can lean on the "big extension cord" from the barn for backup charging, you are in really good shape overall. No need to stress about a generator except for emergency backup.
An all-in-one inverter will be a good option. Some offgrid users don't like their idle power draw, but since you have the grid to back you up, you have so many fewer things to worry about during the winter. The size of the inverter will be driven by your big power devices. Focus on those.