Reminder!
Verify the lowest ambient temperature of the installation location. The rated Voc on the solar module
nameplate is obtained at STC (77°F/25°C). As the ambient temperature drops, the solar module Voc
increases. Please ensure the maximum solar string voltage, corrected at the lowest temperature, does
not exceed the inverter’s maximum input voltage of 480VDC.
PV Input Data Description
DC Input Voltage Range Range required for the unit to operate up to max input 100–480 VDC
Load Output Minimum Voltage Minimum voltage needed to output power on Load side >140 VDC
MPP Operating Voltage Range Range where the MPPT can track 120–385 VDC
Nominal MPPT Voltage The MPPT will operate most optimally at this voltage 320 VDC
Nominal MPPT Amperage The MPPT will operate most optimally at this amperage 17A
Maximum MPPT Amperage
The MPPT can accept up to this amperage (clipping will
25A
Maximum Utilized Solar Power
Watts the unit can utilize from array after considering all
power loss factors
8kW
4.4.2 STRING SIZING
When solar modules are put in a series string, the voltage multiplies times the number of
modules and the amperage stays the same as each module.
For example: Using solar modules that have a 40VDC Voc (@77ºF) with a Max Power
amperage of 10 Amps (Imp) - 10 modules wired in a series string would have a Voc of 400
VDC (@77ºF) and a string amperage of 10 Amps. When the temperature lowers, the voltage
can rise above the maximum allowed by the inverter and damage will result.
CAUTION: To determine how many modules you can have per string; first verify the lowest
possible ambient temperature of the installation location. Next, find the rated Voc, Vmp, Isc and
Imp of the solar module at 77ºF and the temperature coefficients for voltage and power. Then
calculate highest possible Voc for the entire string when the ambient temperature falls to the
lowest possible ambient temperature upon sunrise. To make this calculation, use a string
calculator or consult your solar designer or solar electrician.
DANGER!
Damage WILL Occur if the string voltage exceeds the inverter’s maximum input
voltage of 480VDC!
Finally, calculate the maximum current of the string (Isc) so as not to exceed the Inverter’s
MPPT circuit ratings of 25A (see note at end of section). Double check if the calculated Vmp
range is within the 120-385 VDC optimal MPPT circuit operating range. It is recommended to
consult a solar designer for assistance.
FOR ALL MODULES, THE CALCULATIONS NEED TO BE PERFORMED OR VERIFIED BY
USING A STRING CALCULATOR OR CONSULTING A PROFESSIONAL.
The inverter has two MPPT PV charging circuits. MPPT #1 and #2 will utilize up to 17 amps, which
means two strings can be paralleled for any modules having less than 8.5A (Imp) rating.
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