String/wiring question

[bosco]

Hi – I have a ground mount system that will have two arrays, and four strings.

I also have two inverters – each with 2 MPPTs

Because of the inverter(s) voltage limitations - I need to use all 4MPPT’s - one per string.

My question - based on my research, I will need to run a positive and negative per string in the conduit all the way back to the inverters plus a ground - for a total of nine wires. Can someone please confirm that this is accurate?

thank you so much and please let me know if you have any questions

Steve

[ButchDeal]

Because of the inverter(s) voltage limitations - I need to use all 4MPPT’s - one per string.

Why? just run 4 strings, combine two sets of two so you only have 2 sets of wire runs not 4.
you then only use 2 MPPTs (one per inverter).

My question - based on my research, I will need to run a positive and negative per string in the conduit all the way back to the inverters plus a ground - for a total of nine wires. Can someone please confirm that this is accurate?

put the combiners at the array. also best if you use combiners with disconnects built in.

If you haven't purchased the inverters yet you could combine all 4 strings into 1 set of wire and use one inverter with one MPPT.

[bosco]

Thank you for the quick reply –I’ve already purchased the inverters – now I’m just looking at purchasing wire. Not following your advice to combine because by the time I get to the inverters, I have four separate MPPT‘s to deal with.

[ButchDeal]

Thank you for the quick reply –I’ve already purchased the inverters – now I’m just looking at purchasing wire. Not following your advice to combine because by the time I get to the inverters, I have four separate MPPT‘s to deal with.

what inverter model? many will allow you to use just one with combined strings, and a configuration setting.

[bosco]

Growatt 7000 – I have to use both MPPT’s voltage limitations (600 V max). So that is my fundamental question - one positive and one negative per string plus a ground - correct? Thank you so much

[ButchDeal]

Growatt 7000 – I have to use both MPPT’s voltage limitations (600 V max). So that is my fundamental question - one positive and one negative per string plus a ground - correct? Thank you so much

By putting two strings in parallel the voltage does NOT change.
However looking at the Growatt 7000TL3, it looks like the amperage is limiting you. you might have to check with Growatt about your specific configuration.

Yes you would need a + and - wire for each string. ground can be combined though.

[bosco]

Thank you!