Enable loss diagram for PVWatts

[janinefreeman]

Values are already calculated, just need to be output and displayed.

[brtietz]

I'm going to co-opt this issue a bit based on a discussion during this week's SAM meeting: the battery models (stand alone battery) could also use loss diagrams. This could include:

• Additional detail on battery internal losses in the existing PV-Battery loss diagram
• Loss diagrams for generic and stand alone batteries

A consideration is that the battery losses are likely to change over the lifetime. Are year one values useful here or do we need to represent the lifetime losses in these diagrams?

[janinefreeman]

I would think that a first-year diagram would be most useful here, and likely separated for Battery vs PV? But we'd definitely love some user input on this one!