Planning new install - Panel location opinion / assistance

[KalebTheMaker]

Hi all,

Now that winter solstice has come and gone, I am ready to start my new installation! I have been planning and talking with a few vendors, working out design and quotes and so far so good. I'll post another thread on the full system design, but I wanted to get your opinion on the two options I have for panel placement.

There are two locations for panel placement, the primary site looks pretty great, and the secondary site is not so great. The reason I am not just using the primary site is that it is about 1000' feet from my house and shop. The secondary site is about 200-250' from the house and shop. I have another post about that issue here:

https://diysolarforum.com/threads/1...te-to-house-shop-questions.51389/#post-652274

I am close to the end of the planning stage of this project, and here is a brief description of the system.

I will have about 9500-10000w of panels, and 600Ah of 48v LiFePO4 batteries. Victron RS charge controllers, and two Victron Quattro's for a split-phase system. I will probably have two strings in the panels, with 4 DC conductors running the 1000' or 250' to my "power shed" where the Victron equipment will live. I don't plan to discharge to 100% daily on this system. I am sizing it this way for running my shop, which does not run at full capacity every day. It's sized this way for when I have to run the CNC or welders.

My question to you all, is do you think that the secondary location is "good enough", or should I spend the extra money on ~800' more of conduit, conductor, and pull boxes?

According to https://footprinthero.com/solar-panel-charge-time-calculator I should be able to charge from 100% DOD in 3.8 peak sun hours.

Here are a few pictures I stitched together from a sun path app I found (the app is called "suns path" on IOS). I took these pictures on Dec 20th, 2022.



Note: On the secondary site, all of the close oak trees will be cut down for firewood. The fir trees in the background are further up the ridge, and out of my control.

Any input is appreciated.

Thanks,
-Kaleb

 

[sunshine_eggo]

My question to you all, is do you think that the secondary location is "good enough", or should I spend the extra money on ~800' more of conduit, conductor, and pull boxes?

First, I assume you're not equating total hours to peak solar hours. While 3.8 hours empty to full is pretty easy during non-winter periods, it's very challenging in Winter. Worth considering your typical need as well.

It's a money game.

primary: More conductor money.
secondary: More generator gas money.

Something I would be concerned about with the secondary is the partial shading implications. That 4 hours looks to be further reduced by partial shading risk.

 

[Arron]

Besides the extra cost of the cable run, you have the extra resistive losses in operation (as I refer to in your other thread).
As your shorter run has a quarter of the length, it will have a quarter of the power loss.
As mentioned on the other thread, you could easily have around 1000W of loss in you long cable run from just 20Amps
On this shorter run the loss would drop to 250W.
The shorter run would also cheapen the cost of running a cable for each panel group (5000W plus 5000W).
example:
1) 10000W (500V at 20A) over 1000ft (2.2Ohms for a wire pair) is 880W
2) 10000W (500V at 20A) over 250ft (0.55 Ohms for a wire pair) is 220W
3) 5000W (500V at 10A) over 250ft (0.55 Ohms for a wire pair) is 55W
4) 5000W plus 5000W at 250ft with a cable for each panel combined at the charger end will give a loss of 110W

There are other losses in all the joints to allow for as well.
However, as you can see your operational losses can make a big difference, and will reflect on payback.
You may well see a 7 to 10% decrease in power received at the MPPT because of the longer run.
You will need to operated a higher voltage panel install at either site, to save on losses.
This should be connected up and commissioned by somebody with experience and qualifications.
When you are working with many hundreds of volts, you do not get to make many mistakes, usually ONE!

Four hours of direct unshaded solar in the best hours of the day is not bad for the middle of winter.
As you are going to clear the trees in the foreground, that makes a big difference.
One slight cause for concern is which species of pine is growing in the neighbours land.
Find out how tall these trees will get.

 

[Quattrohead]

The problem and solution is simple.......if the panels are not getting FULL CLEAR sun, they are not producing worth a crap.
So run that long cable and keep your voltage as high as you can to minimize the loss.

 

[Zwy]

Hi all,

Now that winter solstice has come and gone, I am ready to start my new installation! I have been planning and talking with a few vendors, working out design and quotes and so far so good. I'll post another thread on the full system design, but I wanted to get your opinion on the two options I have for panel placement.

There are two locations for panel placement, the primary site looks pretty great, and the secondary site is not so great. The reason I am not just using the primary site is that it is about 1000' feet from my house and shop. The secondary site is about 200-250' from the house and shop. I have another post about that issue here:

https://diysolarforum.com/threads/1...te-to-house-shop-questions.51389/#post-652274

I am close to the end of the planning stage of this project, and here is a brief description of the system.

I will have about 9500-10000w of panels, and 600Ah of 48v LiFePO4 batteries. Victron RS charge controllers, and two Victron Quattro's for a split-phase system. I will probably have two strings in the panels, with 4 DC conductors running the 1000' or 250' to my "power shed" where the Victron equipment will live. I don't plan to discharge to 100% daily on this system. I am sizing it this way for running my shop, which does not run at full capacity every day. It's sized this way for when I have to run the CNC or welders.

My question to you all, is do you think that the secondary location is "good enough", or should I spend the extra money on ~800' more of conduit, conductor, and pull boxes?

According to https://footprinthero.com/solar-panel-charge-time-calculator I should be able to charge from 100% DOD in 3.8 peak sun hours.

Here are a few pictures I stitched together from a sun path app I found (the app is called "suns path" on IOS). I took these pictures on Dec 20th, 2022.
View attachment 125973

View attachment 125974
Note: On the secondary site, all of the close oak trees will be cut down for firewood. The fir trees in the background are further up the ridge, and out of my control.

Any input is appreciated.

Thanks,
-Kaleb

I'd look at the equinox's also.

Any other possible sites? Using multiple higher pole mounts can help eliminate some shading. Usually costs more though. Higher on a hill can help too.

The 200' location I wouldn't even consider unless it was a secondary array to primary. Mainly for summer output.