Strings in parallel and series

[nova]

I was watching a few Utube video's on GT installs, they had one string in series and a second in parallel.

They gave no reason for wiring both ways into one sms inverter.

Any idea why this was done that way?

[emartin00]

can you link to the video? Maybe they were saying the second string was in parallel to the first?

[Amy@altE]

An inverter can only take so many volts in. Let's use twenty 250W 60 cell panels for an example, and a 5000W inverter. If the panels output 38V each, and the inverter can only take up to 550V, if you wired all 20 panels in series, you would have 760V going into the inverter, and you'd have a blown up inverter on your hands. But if you wired them into 2 parallel strings of 10 in series, you'd have 380V going into the inverter. Since voltage increases in series, and current increases in parallel, you can use all 5000W of solar panels in the inverter.

[nova]

Assuming the inverter( in your example of 20 panels), had the capacity to handle 760 volts.

Is there an advantage wiring one way or the other.

Or is there an advantage/disadvantage assuming the inverter can handle 2 string inputs

splitting 10 panels in series on one input and the other 10 in parallel on the other input.

[Amy@altE]

The higher the voltage string you use, the lower the current, and therefore the smaller wire you can use. But in the US, I believe all residential inverters are only up to 600V.

Depending on the inverter you use, it may have dual MPPT inputs, which allows you to use a single string into each input, thus managing the 2 strings independently of each other, so soil or shade on 1 string won't effect the other string. But you'll need to run 2 sets of wire back from the array, as opposed to combining the 2 strings into 1 on the roof and only bringing 1 bigger set of wires back.

[nova]

ok, got it

thanks

[Sunking]

The higher the voltage string you use, the lower the current, and therefore the smaller wire you can use. But in the US, I believe all residential inverters are only up to 600V.

600 is the limit here in the use for residential (NEC) In UK it is 1000 volts. Commercial in USA can go higher but not residential.