Well here's a saga.
We bought a new house about 10 months ago. It has 11kw+ panels, dual inverters, and a whole lot of batteries (very precise I know .... I'm not good with power). Not offgrid, still connected to mains etc.
Many mishaps later including smelling burning electrics, losing power regularly .... could not get the mob who did the install to come do some checks. And we were not looking for any "included" service, we were perfectly willing to pay. No fewer than 10 times calling them, and getting the "the tech will call you back in 10 mins", nothing. Hubby finally just turned up to the office a few times and STILL got the runaround.
Managed to find another sparky with some solar experience around. Turns out the inverters are 3kw only, so they really don't like having 11kw+ being fed in. The batteries, despite being less than 2 years old are completely toast, again, because the amount of power going in and out of them was not properly regulated.
So the previous owners spent >$40k which was just totally money down the drain, because of such a shonky install and setup.