TheTallOne
New Member
Hello everyone. Beginner here with a professionally installed array that I'm looking to add to.
TL:DR: My inverter has two PV inputs. Do the calculation for max string size apply to the array in total, or each string going into the inverter individually.
I think I must be missing something obvious here, so I can only apologise if it's staring me in the face. Here's the situation:
We have an East/West 4.4kw PV Array consisting of two strings of 7 LG Neon2 All Black 320w panels (14 panels total). I assume they are wired in series, I don't know for sure as I didn't wire them but I gather that's by far the most common setup for this kind of array.
The inverter is a Goodwe 3600 D-NS String inverter. (2 MPPT)
Here's the question.
I would like to expand the array on the West facing roof side (I don't have space on the East side). I've got enough space to add another four panels of similar size. The problem is the inverter.
If I've done my sums correctly, my Voct for the array as a whole right now stands at 604. The maximum input voltage on the inverter is 580. So, I'm already over the absolute edge of what the inverter can take at the lowest all time temperature (-7°C here)
(For ref: Panel VOC: 40.8. NOCT temp 20°C. Temp delta: 27°C Temp coefficient -0.27% Voct 43).
But am I interpreting the numbers correctly? I've looked at a bunch of inverters rated for higher output and they all have a max input voltage of no more than 600. How can this be? Surely this would put a hard limit on the number of panels that falls WAY below the max DC power input of the inverter.
Am I missing something here? Is the max input voltage per input (my inverter has two) instead of total?
I'm not adverse to changing the inverter for a hybrid as I'm considering a battery in the long term anyway and I gather that would simplify matters, but I feel like I'm missing a crucial element of this puzzle.
Any and all help appreciated!
Jon.
TL:DR: My inverter has two PV inputs. Do the calculation for max string size apply to the array in total, or each string going into the inverter individually.
I think I must be missing something obvious here, so I can only apologise if it's staring me in the face. Here's the situation:
We have an East/West 4.4kw PV Array consisting of two strings of 7 LG Neon2 All Black 320w panels (14 panels total). I assume they are wired in series, I don't know for sure as I didn't wire them but I gather that's by far the most common setup for this kind of array.
The inverter is a Goodwe 3600 D-NS String inverter. (2 MPPT)
Here's the question.
I would like to expand the array on the West facing roof side (I don't have space on the East side). I've got enough space to add another four panels of similar size. The problem is the inverter.
If I've done my sums correctly, my Voct for the array as a whole right now stands at 604. The maximum input voltage on the inverter is 580. So, I'm already over the absolute edge of what the inverter can take at the lowest all time temperature (-7°C here)
(For ref: Panel VOC: 40.8. NOCT temp 20°C. Temp delta: 27°C Temp coefficient -0.27% Voct 43).
But am I interpreting the numbers correctly? I've looked at a bunch of inverters rated for higher output and they all have a max input voltage of no more than 600. How can this be? Surely this would put a hard limit on the number of panels that falls WAY below the max DC power input of the inverter.
Am I missing something here? Is the max input voltage per input (my inverter has two) instead of total?
I'm not adverse to changing the inverter for a hybrid as I'm considering a battery in the long term anyway and I gather that would simplify matters, but I feel like I'm missing a crucial element of this puzzle.
Any and all help appreciated!
Jon.