IQ8 PV Module Rating Larger Than Inverter Rating

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Theory
Sizing starts by ensuring that PV modules are electrically compatible with the inverter. Enphase provides an online module
compatibility calculator to determine electrical compatibility, purely based on the inverter DC input voltage and current
ranges: https://enphase.com/en-us/support/module-compatibility.
The relationship between PV module power rating (P
DC STC
) and inverter output power rating (P
AC MAX
) is often referred to as
the DC: AC ratio:
DC:AC ratio = P
DC STC
/ P
AC MAX
Enphase Microinverters safely limit inverter power output electronically at the peak output power rating. Microinverters
are tested for reliability in these conditions and have no DC:AC ratio limitations.
Important factors while deciding DC:AC ratio
There are lot of factors which needs to be considered while deciding the DC:AC ratio. Among these, two of the most
important ones are discussed below.
1. Module Degradation
Power of a Module degrades every year. In this paper, the module degradation is taken as 2% for the rst year and
0.4% each year after that. This degradation is in line with the top modules in the markets currently. Below gure
illustrate Module Degradation over 25 years for various modules ranging from 300W to 600W.