DIY'er starting the journey

[diegodog]

Hello All,

I'm planning on installing a grid-tie system with (60) Hyundai 305W HIM-M305. The system will be on ground level in the middle of a 20 acre field in northern Maine. No shadows and no obstructions. I have plenty of room so I'm going with less efficient panels to save $$. There are no inspection to worry about or permits aside from getting the sign off from the power company. I am leaning toward a string inverter. The brand that I have seen the most of so far is the SMA Sunny Boy. Can you guys help me out narrowing down the inverter? Do I want something like the SMA Tripower or possibly 2 smaller 10,000watt inverters?

I am also a little confused on if optimizers are needed.

Sorry for the noob questions.

[bcroe]

With no shadows, the simplest, most efficient, and cheapest would be simple string inverters. Optimizers would have
nothing to do, except add more points of potential failure. Maybe 3 strings of 10 on each inverter. Bruce Roe

[sunnyguy]

2 of the new sb7.7 should be good. That would be a 1.19:1 DC to ac sizing ratio which should perform well. And they are only $2k each.

[diegodog]

Thanks for the feedback so far everyone I really appreciate it.

Here goes another noob question (thanks for the patience) ...

How many string can each inverter typically handle? All the videos I have seen thus far have only had 2 string systems. While they showed the install it appeared there were only enough connectors to install a string of 2. Is there a way around this? Once again I could be oblivious to the obvious.

It seems 2-3 smaller inverters are recommended over 1 larger one. Any reasoning behind this?

Other known unknowns I have is how far away can the panels be from the electric panel. Obviously shorter runs are better but is a perfect spot worth a little extra distance away?

Since I do not have the shadow or roof direction issues will my system flow be as simple as Sun - Panels - Inverter - DC disconnect - AC Electric Panel?

[foo1bar]

Other known unknowns I have is how far away can the panels be from the electric panel. Obviously shorter runs are better but is a perfect spot worth a little extra distance away?

Longer runs means more lost to wire resistance and/or larger wire needed to decrease the resistance.
If it's 5 feet longer so it's on the north side of the building or inside in the shade, it's probably a better solution (since you want the inverter to be in the shade because it's likely to run cooler and last longer that way.)
If it's 200 feet longer it may be more of a PITA and you'll be OK with a "good" spot instead of a "perfect" spot.

Since I do not have the shadow or roof direction issues will my system flow be as simple as Sun - Panels - Inverter - DC disconnect - AC Electric Panel?

The "DC Disconnect" in your list is after the inverter. So either you misplaced it, or you meant "AC disconnect"

All the videos I have seen thus far have only had 2 string systems. While they showed the install it appeared there were only enough connectors to install a string of 2. Is there a way around this? Once again I could be oblivious to the obvious.

I believe most string inverters will have 2 MPPT inputs. (for residential sizes at least)
I *think* that you can have two strings connected to one MPPT input if the two strings are identical like you are planning (same orientation, same number/size/type of panel, both shade-free).
You'd still need to make sure the two strings were OK from max/min voltage and max current requirements.
I'm sure you can find more information by doing some searches on it or asking the manufacturer. But I'd probably look at 1 string per MPPT first - my guess is it's probably the most common approach.

[sunnyguy]

How many string can each inverter typically handle?

It seems 2-3 smaller inverters are recommended over 1 larger one. Any reasoning behind this?

It depends on the inverter. The sb7.7 has 3 mppt inputs. The fronius primo has 2 mppt inputs with up to 2 strings each. Then you have to check how many amps can each mppt support, what is the ideal input voltage.

Inverters over 10kw are usually three phase power output for commercial installations. Residential inverters are single phase, smaller, and high efficiency. The more inverters, the more mppt inputs. Residential installs often have arrays on different roof surfaces and orientations or with shading that need their own mppt. Microinverters are the extreme case of this. One inverter is also a single point of failure.

[bcroe]

How many string can each inverter typically handle? All the videos I have seen thus far have only had 2 string systems. While they showed the install it appeared there were only enough connectors to install a string of 2. Is there a way around this? Once again I could be oblivious to the obvious.

It seems 2-3 smaller inverters are recommended over 1 larger one. Any reasoning behind this?

Other known unknowns I have is how far away can the panels be from the electric panel. Obviously shorter runs are better but
is a perfect spot worth a little extra distance away?

If the setup is as shade free as you said, there is no need for multiple MPPT inverter inputs. I like 2 identical inverters;
when everything is good, they will have near identical outputs. Put the system in the best place, and spend a little more
for bigger wire if needed. Mine is completely out of my sight and anyone elses as well. Bruce Roe

[emartin00]

I've gotta ask, where in Northern Maine are you? I'll be up there in a couple of weeks.

That's one heck of an array. Is it way over your power usage?