4kW worth of panels and a 3.6kW inverter

[GaryM]

I'm due on the C&G 2399 course next week and hopefully I'll come away with more answers than questions but one thing I keep seeing is inverters seemingly over rated in that a 3.6kW inverter is recommended for a 4kW system.
Could anybody please offer a brief reasoning behind this?

 

[MorganPVI]

When solar panels get hot (like when the sun is shining on them) they get hot, the hotter they get the less power they produce. Therefore under real world conditions it is very unlikely you will get anywhere close to a constant 4kw system.

We regularly install a 3.3kw inverter on a 4kw system.

 

[Daz Hodson]

Inverters work better when working at maximum capacity. Your computer design programme will design a 4kw system in terms of number of panels and total wattage but with orientation of building, angle of roof and other survey factors mean that the realistic out put could be 90% - 80% - 70% of the system.

Dont get confused just because you have 4000 watts of panels doesnt mean 4000 watts of power.

 

[SolarCity]

Inverters work better when working at maximum capacity.

I agree with your there. I think. I've only ever heard of one person claim that this wasn't the case. Unfortunately, he happened to be part of technical support at SMA.