PVI 3000/4000/5000/5300
Installation and Operation Manual
46
7 Technical Data
Technical Information and specifications – also
see PVI 3000-5300
brochure for information and on the inverters. (see Appendix B for info).
Input (DC) from PV array:
Maximum open circuit voltage of PV array: 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.
See PV string sizing chart example in Appendix C.
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. (See the
following figure – Fig. 7.5)
0
2
4
6
8
0
10
20
30
Voltage (VDC)
DC Current (A)
at 50 deg C
at 20 deg C
at -20 deg C
Fig. 7.1 Example representative ~100W PV module voltage –
current characteristic at various cell temperatures
Because PV modules also have a reduction in voltage at high cell temperatures, you must make sure the MPP voltage of the
strings will not drop below the minimum inverter DC input voltage of 200V DC in very hot temperature conditions, including
wire losses/voltage drop.
Both the maximum open circuit voltage (OCV) when at cold extreme and minimum MPP 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/should be used in a string.