It's fairly easy and there are a lot of forums around with knowledgeable people.
My main issue was ensuring wire gauges were correct. One's intuition about dealing with house wiring @15A changes when you're dealing with 50A circuits. Also you need to pay attention to things like equal cable lengths between battery banks so you don't overcharge one battery in a series.
However, I'm dealing with an off-grid cabin so I don't need to deal with any grid-tie circuitry, which would make it much more difficult and I'd definitely get an electrician for that.
My main issue was ensuring wire gauges were correct. One's intuition about dealing with house wiring @15A changes when you're dealing with 50A circuits. Also you need to pay attention to things like equal cable lengths between battery banks so you don't overcharge one battery in a series.
However, I'm dealing with an off-grid cabin so I don't need to deal with any grid-tie circuitry, which would make it much more difficult and I'd definitely get an electrician for that.