Installation and Operation Manual (Rev E)
SGI Series Inverters
DOCR-060371
45
9.0 Technical Data
Input (DC) from PV array:
Maximum open circuit voltage of PV array is 600V DC
WARNING:
NEC 690-7 must be followed to calculate the maximum number of PV
modules allowed for a maximum inverter open circuit voltage (OCV) of 600V DC in
extreme cold temperatures for the installation location.
The open circuit voltage of PV modules depends on the cell temperature and the solar
irradiation. The highest open circuit voltage occurs when the PV modules are at the
coldest temperature and in bright sun.
Because the PV modules also have a reduction in voltage at high cell temperatures, you must
make sure the MPPT voltage of the strings will not drop below the minimum inverter DC input
voltage in very hot temperature conditions.
Both the maximum open circuit voltage (OCV) when at cold extreme and minimum MPPT
voltage when at hot extreme can be calculated for a PV module using its specification sheet. PV
module string sizing can then be used to determine how many modules can be used in a string.
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