Do I have to upgrade my inverter if I want to add more solar panels to my roof?
The reality is that if you have a system now and buy it, the inverter usually regulates how much you are allowed to put on. So a 6.6 kilowatt system in panel actually often uses a five kilowatt inverter. So people are a little bit confused and say, how can you use a five kilowatt inverter with the 6.6 kilowatts of panel. You're allowed to oversize the inverter by one third by the manufacturer, no problem.
The reason is, they'll give you a 331 panel. In most cases under the Austrian lighting condition, that panel will only generate about 280, 290 Watts of electricity because they're measured under a thousand Watts of light hitting them. But the reality is Australian light level is 800 Watts in many cases. In Europe, it's 400. So the fact is that we can oversize.
If I now, in future years, say I want to add additional panels, you can't really because the 6.6 has reached the inverter limit. If, on the other hand, you say, look, I put a five kilowatt inverter in and I only put four kilowatts of panels on it, then you can add it, but it is much easier if you do that with the microinverter, or even with the optimizer solution, because in that case, those panels being treated individually means you can add additional panels without the issues of compatibility.
If you've got a one and a half kilowatt system that works fine, even if the inverter gets towards its end, my advice is, for the environment and everything, keep it going. But if you need more solar at that point in time, add a new system to it. If, on the other hand, that system was a relatively cheap system has come to the end of its life, in that case, you would remove it, especially if it sits in a strategic spot right in the middle of the system, and you start again. And the common size now is about a 6.6 kilowatt system.