System Expansion - Help Needed

[jdrazzz]

Hello Friends,

I'd love to have your opinions on my expansion plans.

It's been almost 2 years since I installed my 10KW On-Grid solar plant at my residence. Now I'm planning on expanding it to a max input of 15KW to maximise productivity (Output max up to 10kw) as my energy consumption increased by what's being produced.

Here are the specs of my current plant:

Inverter:
Sungrow On-Grid Hybrid 10kw SH10RT. I've not installed batteries yet.

PV Input
Max PV input power 15kw
Nominal Input Voltage 600V
# of MPPT 2
Max PV Strings per MPPT 1/2
MPP Voltage range 200-950V
≤12.5 kW if string voltage is lower than 500 V
≤ 10 kW if string voltage is between 500 V and 800 V
≤ 8 kW if string voltage is between 800 V and 1000 V
Max PV Input Current 25A(12.5/12.5)
Max Current for Input Connector 16A
Short Circuit Current of PV Input 48A(16/32)

AC Input and Output
Nominal AC output power 10KW
Nominal AC output current 14.5A
Max. AC output current 15.2A

Current Panels:
21 Jinko Tiger JKM475M-7RL3-V
Max Power (PMax): 475w (STC); 353w (NOCT)
VMP: 43.38v; 30.8v
IMP: 10.95A; 10.88A
VOC: 52.25V; 49.33V
ISC: 11.77A; 9.51A

Expansion Panels: we don't have less than 575W panels available in the country anymore (by any brand) so these are my best options.

Jinko Neo N-Type JKM585N-72HL4-V
Max Power (PMax): 585w (STC); 440w (NOCT)
VMP: 42.52v; 39.81v
IMP: 13.76A; 11.05A
VOC: 51.16V; 48.6V
ISC: 14.55A; 11.75A

Technical Questions:
1. Since these are two different type of panels I should install them on separate MPPT and how many strings per MPPT?
2. What's the max # of my old panels can I retain on MPPT 1.
3. How many of new panels can I install on MPPT 2?

My goal is to get as close to max 15,000kw PV input as possible. I'm aware that there will be clipping but it will only happen during peak hours and if clipping doesn't affect the Inverter adversely then I'm fine with it as we'll get more power during other hours.

Thanks a lot for your help and looking forward to your suggestions.

 

[sunshine_eggo]

PV Input
Max PV Input Current 25A(12.5/12.5)
Max Current for Input Connector 16A
Short Circuit Current of PV Input 48A(16/32)

Looks like you need to limit Isc of string 1 to 16A and string 2 to 32A.

Current Panels:
21 Jinko Tiger JKM475M-7RL3-V
Max Power (PMax): 475w (STC); 353w (NOCT)
VMP: 43.38v; 30.8v

Typo?

IMP: 10.95A; 10.88A
VOC: 52.25V; 49.33V
ISC: 11.77A; 9.51A

Expansion Panels: we don't have less than 575W panels available in the country anymore (by any brand) so these are my best options.

Jinko Neo N-Type JKM585N-72HL4-V
Max Power (PMax): 585w (STC); 440w (NOCT)
VMP: 42.52v; 39.81v
IMP: 13.76A; 11.05A
VOC: 51.16V; 48.6V
ISC: 14.55A; 11.75A

Technical Questions:
1. Since these are two different type of panels I should install them on separate MPPT and how many strings per MPPT?

Since the VMP of the two types is very similar, you could parallel them on the same MPPT provided you don't exceed the input current rating of the MPPT. Unfortunately, your MPPT ratings are restrictive.

2. What's the max # of my old panels can I retain on MPPT 1.
3. How many of new panels can I install on MPPT 2?

I wouldn't do this. I would put 10S2P of your old panels on MPPT2
and 10S of the new panels on MPPT1.

This would yield 15,250W

With both MPPT limited to 12.5A Imp, you're slightly over-paneled on MPPT1 and most of the entire second string on MPPT2 is over-panel. Both MPPT will get clipped.

 

[jdrazzz]

Looks like you need to limit Isc of string 1 to 16A and string 2 to 32A.




Typo?






Since the VMP of the two types is very similar, you could parallel them on the same MPPT provided you don't exceed the input current rating of the MPPT. Unfortunately, your MPPT ratings are restrictive.




I wouldn't do this. I would put 10S2P of your old panels on MPPT2
and 10S of the new panels on MPPT1.

This would yield 15,250W

With both MPPT limited to 12.5A Imp, you're slightly over-paneled on MPPT1 and most of the entire second string on MPPT2 is over-panel. Both MPPT will get clipped.

Yes, it's a typo.

Old Panels VMP is 43.38V/39.8V

 

[jdrazzz]

Looks like you need to limit Isc of string 1 to 16A and string 2 to 32A.




Typo?






Since the VMP of the two types is very similar, you could parallel them on the same MPPT provided you don't exceed the input current rating of the MPPT. Unfortunately, your MPPT ratings are restrictive.




I wouldn't do this. I would put 10S2P of your old panels on MPPT2
and 10S of the new panels on MPPT1.

This would yield 15,250W

With both MPPT limited to 12.5A Imp, you're slightly over-paneled on MPPT1 and most of the entire second string on MPPT2 is over-panel. Both MPPT will get clipped.

Pardon my ignorance, when you say 10S2P or 10S, what do you mean?

 

[DIYrich]

Pardon my ignorance, when you say 10S2P or 10S, what do you mean?

10s is 10 panels on one string.
2p is parallel 2 strings (of 10 panels).