Max. PV input voltage

LesAviois

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Joined
Apr 30, 2022
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2
Hello,
Asking about Sungrow SG12RT and pairing it with 19 Longi LR4-72HIH-450M and 11 Longi LR4-60HPH-375M.


Max. PV input voltage 1100 V
MPP voltage range 160 V–1000 V
No. of MPPTs 2
Max. number of PV strings per MPPT 2 / 1

Is the 1100V max PV input voltage for the whole Unit, per MPP or per String?

On the website where I order from they say that SG12RT is 12000W. In the manual Max. PV input power is 18000W.
Can I connect 18000W(+20-30%) of panels to this inverter?
The price is about the same for the SG10RT and SG12RT so going down 1-2 models don't save me much money and I might be installing more panels in the future.

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sunshine_eggo

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Hello,
Asking about Sungrow SG12RT and pairing it with 19 Longi LR4-72HIH-450M and 11 Longi LR4-60HPH-375M.


Max. PV input voltage 1100 V
MPP voltage range 160 V–1000 V
No. of MPPTs 2
Max. number of PV strings per MPPT 2 / 1

Is the 1100V max PV input voltage for the whole Unit, per MPP or per String?

Unless this company specifies it completely different from everyone else, 1100Voc per MPPT. Separate MPPT array voltages don't add to each other.

Note that you need to stay under ~950Voc to allow for cold temperature voltage spikes. If you never get under 10°C, then you can probably get away with 1000Voc. Check your panels' temp coefficient.

Note that there is an asterisk (*) by the Max PV Input Voltage. You should find out why.

On the website where I order from they say that SG12RT is 12000W. In the manual Max. PV input power is 18000W.

The two MPPT are not equal. MPPT 1 has a PV input current max of 25A and the other 12.5A for a total combined of 37.5A. This means that MPPT2 can only handle half of what MPPT1 can.


Can I connect 18000W(+20-30%) of panels to this inverter?

As long as your Voc does not exceed the 1100V limit with temperature buffer and your array Isc doesn't exceed 32A on MPPT1 and 16A on MPPT2, you can put a crap ton of PV on them.

Lets say you have 950Voc on on each MPPT. That's going to be about 800Vmp.

MPPT1 = 800Vmp * 25A max = 20,000W
MPPT2 = 800Vmp * 12.5A = 10,000W

Getting 30kW on that unit is feasible. The unit should never pull more than what it can send to the battery/loads.
 

foggysail

Solar Enthusiast
Joined
May 5, 2022
Messages
45
OK--- I am getting prepared for my home installation BUT I HAVE A QUESTION:

WHY IN THE WORLD WOULD ANYBODY want to work with 1000VDC????? Sure, wire losses will be contained but 1000VDC is DANGEROUS! You should also verify that the wire insulation is good for 1000V
 

rhino

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Jun 6, 2020
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Location
Minnesota
Also have to be careful about any wiring or other items typically available for residential systems used to connect that high of voltage since most are rated only to 600V.
 

rhino

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Location
Minnesota
The * is for:
* The inverter enters standby state when the input voltage ranges between 1,000 V and 1,100 V. If the maximum DC voltage in the system can exceed 1,000 V, the MC4 connectors included in the scope of delivery must not be used. In this case MC4-Evo2 connectors must be used.
 

RCinFLA

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Jun 21, 2020
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1,768
Assume everyone knows this is a three phase GT inverter.
 

LesAviois

New Member
Joined
Apr 30, 2022
Messages
2
Thanks Sunshine ☀️!
Exactly. It’s a AC 230V system or well 3phase. These systems seem to be 1000-1500V DC.
 
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