Advice on building my 7920KW system off grid solar system

[crustbottle]

Sensij each charge controller is 96v 80a with a 400 volt max. My panels are going to be in series 4 each for around 144 volts. I will have 6 panel arrays that which goes to the dc combiner box then 2 outputs to go to each charge controller. Is that okay?

[sensij]

Sensij each charge controller is 96v 80a with a 400 volt max. My panels are going to be in series 4 each for around 144 volts. I will have 6 panel arrays that which goes to the dc combiner box then 2 outputs to go to each charge controller. Is that okay?

No.

Those panels have a Voc @ STC of 46.34 V. With 24 panels, I'd combine two strings of 6 panels into one charge controller, and two strings of 6 panels into the other charge controller. Two charge controllers can not control the same panels! 6 panels in a string is 278 V, plenty of clearance to the 400 V max. You can not combine all 24 panels and attempt to operate them with more than one CC.

By putting only two strings into each charge controller, you avoid the requirement for overcurrent protection between the array and charge controller, and you can design the wiring to carry 9.29 A * 2 * 1.56 = 29 A, or 10 AWG to the charge controller (if voltage drop over that run is OK).

The STC power into each charge controller is 3960 W. With a 96 V battery, that is 41 A output. With a 48 V battery, that is 82 A output. Either probably works fine with your charge controller. Code requirements get much more extensive when your system voltage is over 48 V, although 6 parallel battery strings is not going to work well, you I think you're in a bind there.

[SunEagle]

No.

Those panels have a Voc @ STC of 46.34 V. With 24 panels, I'd combine two strings of 6 panels into one charge controller, and two strings of 6 panels into the other charge controller. Two charge controllers can not control the same panels! 6 panels in a string is 278 V, plenty of clearance to the 400 V max. You can not combine all 24 panels and attempt to operate them with more than one CC.

By putting only two strings into each charge controller, you avoid the requirement for overcurrent protection between the array and charge controller, and you can design the wiring to carry 9.29 A * 2 * 1.56 = 29 A, or 10 AWG to the charge controller (if voltage drop over that run is OK).

The STC power into each charge controller is 3960 W. With a 96 V battery, that is 41 A output. With a 48 V battery, that is 82 A output. Either probably works fine with your charge controller. Code requirements get much more extensive when your system voltage is over 48 V, although 6 parallel battery strings is not going to work well, you I think you're in a bind there.

That is a good plan if you really need both CC's.

If the OP already has one of the Hexengy MPPT 96V 80amp CC then you could wire in all 24 panels (4 strings of 6) and not have to worry about using 2 CC connected to the same battery system. Now if that CC is only 70amp then a second CC would be needed or reduce the amount of panel wattage to it.

[crustbottle]

sensij you would go from the panels to the charge controller directly or would you have it this way.

6 panel in series string goes to dc combiner box # 1
6 panel in series string goes to dc combiner box # 1
6 panel in series string goes to dc combiner box # 2
6 panel in series string goes to dc combiner box # 2

Then each combiner box goes to the charge controller.

[sensij]

sensij you would go from the panels to the charge controller directly or would you have it this way.

6 panel in series string goes to dc combiner box # 1
6 panel in series string goes to dc combiner box # 1
6 panel in series string goes to dc combiner box # 2
6 panel in series string goes to dc combiner box # 2

Then each combiner box goes to the charge controller.

Yes, this. If you ultimately decide to drop the battery down to 48 V, it might be worth revisiting, but at 96 V, this should be good.

[crustbottle]

What combiner box would you recommend?

[crustbottle]

I thought since my combiner box had two outputs that it would split the wattage down in half. But that would not be the case? do they have combiner boxes that do that?

[sensij]

I thought since my combiner box had two outputs that it would split the wattage down in half. But that would not be the case? do they have combiner boxes that do that?

What specific combiner box are you talking about? Most take multiple inputs, and output just a single DC+ and DC-.

[crustbottle]

midnight has a combiner box like that here is a picture it has on the spec sheet.

[crustbottle]

something like this https://www.youtube.com/watch?v=GMdXeLh02vU

[Mike90250]

.......Their country of origin is not that important.

Yes it is, and combined with the "Mfg's Name" it gives the knowledgeable folk a clue of how far to stand back when loading it up.

[sensij]

something like this https://www.youtube.com/watch?v=GMdXeLh02vU

Yes, something like that would work for you, you'd need to make sure you get breakers rated for the right voltage.

Do you understand the code consequences for a battery system over 48 V?

[crustbottle]

Yes I understand I want to try to make it as safe as possible.

[max2k]

Yes it is, and combined with the "Mfg's Name" it gives the knowledgeable folk a clue of how far to stand back when loading it up.

very true. I was mostly objecting to OP providing country of origin instead of model numbers, that was not very helpful substitute.

[max2k]

Yes I understand I want to try to make it as safe as possible.

Besides safety- do you need to pass inspection to operate it? It depends on your local situation/rules and you might find out too far into the project (and into expenses) that certain components are just 'no go' at your place due to those requirements. Systems > 48V are under different set of rules.