Grid Tie Array voltage problems

Ok, getting closer to completing our Grid Tie project. Our Array consists of 33 - 400w panels wired in series. Originally, the plan was for 3 - 11 panel arrays but due to a change in plan (another Inverter selected), we needed 4 arrays. NOTE: the Inverter has 4 DC + & - inputs

So, we have 3 - 8 panel arrays and 1 - 9 panel array.

The voltage output for Arrays #1, #2 and #3 are fine. The voltage for the 9 panel Array #4 is only about 38% of the output of #1, #2, and #3.

You'll see on the attached wiring diagram, I've wired the 9 panels in series with both the + pv wiring and the - pv wiring terminated at a 3-way splitter.

Again, the voltage for Array #4 is about 38% of the output vs. the other Arrays. When I test the voltage at the 3-way splitter for zones "A" , "B" & "C", each come up with the same output....which is also identical to the output off all circuits hooked up to the 3-way splitters.

Am I just having a brainfart....overlooking the obvious? Why is the voltage output for Array #4 much less vs. the other Arrays? Is the wiring incorrect? Are the 3-way splitters the issue?

Looking fwd to your responses! THNX!!!

The 8 panel arrays are wired 8 in series. Panel voltage x 8 and panel amperage x 1.
The 9 panel array is wired 3s3p. (3 parallel strings of 3 panels in series) Panel voltage x 3, and panel amperage x 3.

timselectric said:

The 8 panel arrays are wired 8 in series. Panel voltage x 8 and panel amperage x 1.
The 9 panel array is wired 3s3p. (3 parallel strings of 3 panels in series) Panel voltage x 3, and panel amperage x 3.

Click to expand...

Ok...Tim, how would you wire (connect) the 9 panels so we'd have panel voltage x 9 and panel amperage x 1 ? For some reason, I'm just punch drunk or something. Isn't taking the 3 +lines and the 3 -lines from each "Zone" and connecting via a 3-way splitter considered a 9 panel array?

PS: so, you're response shows why each 3 panel 'zone's' voltage is the same....and the same when using the multimeter at the + & - 3-way splitters
I had installed and wired the panels a few months ago and swear I tested each array then...must not of.

You would have to wire the 9 panels in series, like the other arrays.
Right now, it's 3 rows of 3 panels in series.
Then the 3 rows are connected in parallel, at the Y connectors.
In series, you add up the voltage.
In parallel, you add up the amperage.

Hate to 'work' you on a saturday night (doesn't matter when you respond...you've been a ton of help!) but...to wire this 9 panel configuration into a 1 array series, how would you do this?
Let's start at zone A from left to right (panels 1, 2 & 3)
Then zone B from left to right( panels 4, 5 & 6)
Then zone C from left to right ( panels 7, 8 & 9)

Like i said, having a brainfart

Any order you want, positive to negative.
All nine panels.
Example: 7,4,1,2,3,6,5,8,9

HEY TIM-ELEC (and other knowledgeable grid-tier's)
OK...here is my draft of 9 panels wired in series on a single string

is this doable?

Without knowing particulars of inverter or panels it is impossible to say how to best connect panels together.

RCinFLA said:

Without knowing particulars of inverter or panels it is impossible to say how to best connect panels together.

Click to expand...

we're good with the particulars of both panels and inverter....does the attached drawing represent a Single String, Panels wired in Series configuration?

PoPoShoo said:

we're good with the particulars of both panels and inverter....does the attached drawing represent a Single String, Panels wired in Series configuration?

Click to expand...

Your polarity is wrong, between 1&4 and 6&9.
All connections should be positive to negative.

See this thread about your panel wiring issue: BTW, is it hard to follow due to more than one thread with the same question.

Some panels wired reverse polarity was my first guess. I've done it (with screw terminals) but most panels these days have MC connectors which makes it pretty much impossible.

"the Inverter has 4 DC + & - inputs"

Inputs? or MPPT?
If that is four inputs for 1 MPPT, then:
1) Each string should have a fuse.
2) The 9s string will get pulled down to voltage of the 8s; you won't get much out of the extra panel.