Newbie in Durango, CO installing off the grid

[dnbuggy]

Hi everyone. Just starting down the road of an off the grid system.

Background info: We purchased 40 acres outside Durango, CO. Our nearest utility connection point is 1500' away. Our local power company charges $25 a foot to run the line plus the cost of a booster and the cost of trenching 3' down. I am estimating well north of $45K to get it all put in.

This led to us thinking about going off the grid. I have begun to see what it would take from a system sizing standpoint and have consulted with a good friend who installs grid tied systems. So far, we are thinking a our needs will be met with a 30kwh daily system.

I have looked at wholesale solar, affordable solar, etc... and they all seem to be under-sizing my needs and quick to quote prices, but not much for answering questions or suggesting alternatives. I can get good pricing through a friend at the local Consolidated Electric Distributor and have come up with the core components of the system below. I would just like to open it up to thoughts, suggestions, etc.... I am new to this and learning more and more every day. Thanks in advance!


27 - sunmodule 325xl panels
1 - Outback FLEXPower Three FP3 FXR3048A Pre-Wired System (possibly even the FP4)

2 - 48V GNB Forklift batteries 1200ah for a total of 2400ah

1 - Generac 15kw generator

[dnbuggy]

Here is the PVWatts data.

[ButchDeal]

27 - sunmodule 325xl panels
1 - Outback FLEXPower Three FP3 FXR3048A Pre-Wired System (possibly even the FP4)

2 - 48V GNB Forklift batteries 1200ah for a total of 2400ah

1 - Generac 15kw generator

There is a FlexPower radian version now , 8k could be a good fit.

[dnbuggy]

There is a FlexPower radian version now , 8k could be a good fit.

I have seen that. What's the difference in the Radian and flexPower?

[ButchDeal]

I have seen that. What's the difference in the Radian and flexPower?

Radian is an inverter, There is a FlexPower radian setup, as well as the FlexPower fx and FlexPower fxr series. The FlexPower series are pre configured wipe th AC and DC breakers, charge controllers, battery monitor, mates etc. the sum of the parts is a savings for the FlexPower versions and a huge savings in instal labor.

[dnbuggy]

Radian is an inverter, There is a FlexPower radian setup, as well as the FlexPower fx and FlexPower fxr series. The FlexPower series are pre configured wipe th AC and DC breakers, charge controllers, battery monitor, mates etc. the sum of the parts is a savings for the FlexPower versions and a huge savings in instal labor.

I phrased my question poorly. I guess I was wondering the difference between the flexpower radian vs the flexpower fxr?

[ButchDeal]

I phrased my question poorly. I guess I was wondering the difference between the flexpower radian vs the flexpower fxr?

Ah, pretty much just the inverter. The radian is 120v and 240v capable the fx(r) is just 120v. Put two fx inverters together and you get 240/120v capability.
The radian has three AC connections (grid,generator,critical load). FX(r) has just two ( grid or generator , critical load).

[sensij]

If I'm looking at the data sheets right, the Radian offers 4 or 8 kW with 120/240 V support. The FXR FP2 package can get you 120/240 V at 7 kW. The FP3 package offers three phase power (208 V L-L) at 9 kW to 10.8 kW, while FP4 offers 120/240 V, but at higher powers than the Radian... 12 kW or 14 kW. The Radian looks least expensive to me for the power you get.

With respect to this project... 30 kWh daily is a huge load for off-grid. Really, by the time you look at the efficiency of the battery system, you'll need the ability to generate at least 40 kWh. Your PVWatts output shows you falling short of that most of the year... were you planning to just supplement with a generator?

With respect to the PV design, you'll want to look at how level that 30 kWh demand is throughout the year. If it is pretty steady, you'd want to tilt the panels more than the 22 deg you used in the PVwatts model. South facing arrays with latitude tilt will tend to produce the most energy overall, but that doesn't help so much off-grid. Increasing the tilt helps make up for shorter days in winter, while less tilt increases generation in the summer, if you are attempting to run cooling loads, for example. You might also want to consider an array split between two faces... either east and west or SE and SW, which will lower the peak power during the day but stretch out the number of hours that peak can be maintained. It is a better approach to a battery system, especially if you use FLA and not AGM.

Do you have a link to the battery you are looking at? Avoiding batteries in parallel will help with longevity, so if you by a pre-built 1200 Ah bank, make sure that it is put together with 24 x 2V batteries in series. Even 2400 Ah at 48 V means you will be discharging 26% daily... you'll need to get the generator going anytime there is rain or clouds that will last more than a day or so to keep the batteries from discharging past 50%.

By the time you really work through this, the $45k for grid power might not seem like such a bad idea.

BTW, if you haven't looked at it yet, here is the sticky for off-grid sizing:

https://www.solarpaneltalk.com/forum/off-grid-solar/off-grid-solar-panel-systems/5140-solar-off-grid-battery-design

For a system as large and expensive as yours, I wouldn't stop there though, you'll really want to map out in detail how this will work for you to a level deeper than the guidelines suggest.

[Sunking]

Pay the POCO, it is a lot better bargain.

[Mike90250]

Trench and power company, will save you money in 5 years.
Add a $400 Automatic Transfer Switch and a $5,000 generator for outages and you have power 99.99% of the time,

[Amy@altE]

I did an interview with Outback Power discussing their FXR and Radian inverter/chargers, and when to use each. Go to YouTube and search "OutBack FXR Inverter/Charger Overview & Features with OutBack Power ".

[Amy@altE]

If you haven't already, you should consider a ground mount that will allow you to either adjust the tilt angle, or at least set it to maximize the winter sun. Another option is to build a purpose designed shed with a steep angle roof to mount the panels on, and give you a bonus storage location. Since you would have a further distance to run the wires, you could use a 600V charge controller (from Schneider or Morningstar) and have longer strings, reducing the voltage drop and minimizing the size of the wire needed. Also take a look at Schneider inverter/charger options, like the Conext SW and XW+, they are comparable to the Outback products you are looking at. The XW+ gives you the ability to connect to the grid in the future, the SW is off grid only.

[ButchDeal]

If I'm looking at the data sheets right, the Radian offers 4 or 8 kW with 120/240 V support. The FXR FP2 package can get you 120/240 V at 7 kW. The FP3 package offers three phase power (208 V L-L) at 9 kW to 10.8 kW, while FP4 offers 120/240 V, but at higher powers than the Radian... 12 kW or 14 kW. The Radian looks least expensive to me for the power you get.

The FP2/3/4 can do 120/240V depending on configuration. The FP3 can do 120/240V OR 3phase again depending on configuration. In other words each inverter can sync to the other in phase or out of phase.

[sdold]

Would the increase in the property's value due to having grid power make up for the cost of having the power brought in? Bringing in grid power vs. putting in an off-grid solar system sounds comparable to building a real, permanent house vs. wheeling in a mobile home.

[dnbuggy]

You all have me seriously thinking of ponying up and connecting to POCO. HMMMM... decision time.