How much can you save doing the engineering of the inverter yourself?
Is it a typical ~400% materials markup? Or do economies of scale bring it down some?
I would like to consider electrical solar power (I use solar thermal water heating, which has actually paid off), but the margins are kind of slim where I live.
I think I can handle doing the roofing work, building/designing load bearing wind and seismic resistant fixtures and mounting the panels by myself to save labor costs, but decent inverters are kind of pricey.
How would a DIY job (assuming you buy the appropriate water proof connectors and don't make ghetto fixtures) save vs just paying the company?
And, another reason for this is because I very much like the Tesla Powerwall, but I know that in terms of making money, it basically prevents the system from ever breaking even (I never did the calculations but I assume it would take at least 20 years to pay itself off and its a battery that will degrade). I don't really enjoy using generators and there are power outages here. Most are under 24 hours, and I don't mind using some chinese shit generator for longer ones, as its basically a state of emergency, but I would prefer a tesla wall to some kind of monster standby generator which I see as a complete pain in the ass high maintenance investment, for at least 3000$.
I don't feel too comfortable making some kind of home made power wall or battery maintainer at this point, unless I figure out a way to make some kind of underground storage unit for the battery bank away from my house), which would have its own challenges of moisture proofing, temperature control, etc.