I am about to get a 1 KW solar system. Normally this would come with a 1 KW grid connect inverter. I am thinking of ordering a larger inverter say 2 KW so I can add more panels latter on without having to also buy a new inverter.

From what I understand the panels are connected in a combination of series panels and parallel groups of series panels so as to not exceed the inverters maximum input voltage and to provide an optimum input voltage.

Someone mentioned there would be efficiency losses using a larger inverter i.e. 1 KW of panels and a 2 KW inverter. Is that correct I would have thought bigger would simply mean the ability to supply more power and providing the panels feed the inverter with the connect voltage it would not matter.

I thought it might be related to the minimum start voltage of the inverter but I can’t find any info on that being an issue. I am looking at using Sunnyboy inverters.