The Solar credits multiplier 5x - (for the first 3 years) applies to the first 1.5kW of generating capacity only.
This means that the bigger the system the smaller the subsidy provided by solar credits. This appears to be leading people to consider a smaller than necessary number of panels and trying to compensate for their perceived needs by altering other parts of the system.
In particular some seem to be thinking/installing a 1.5 kW PV system but using a bigger than necessary inverter presumably with the idea of upgrading latter.
Inverters tend to have greatest efficiency when operating in ‘the middle’ of their rated output and the middle of their voltage range which is set by the type, number and insolation (sun light).
Choosing a larger inverter say 4kW will increase the losses compared with a 1.5-2kW the exact amount will depend on the particular inverter.
Also Wiring power losses and current capability need to be considered in any PV grid/standalone system. The wiring may need to be upgraded or over sized at the start for the upgrade to succeed.
Fuses need to be chosen for the expected current produced by the panels - this will change upon upgrade and will also need to be changed (I would consider it unsafe to use a bigger than necessary fuse for this purpose)
I had a quick look at some inverter specs - some have fairly flat efficiency curves so the losses should be small and leaves fuses and wiring and perhaps other issues,
Please add to this thread if I missed anything….
