Schema feedback

[kandersolar]

A few things I noticed about the schema and test cases:

• The test case json files include Temperature for each IV curve, but that's not included in the schema
• The test case json files set Datetime to the empty string, which I think is not a valid value for the schema's date-time format
• Consider restricting Sweep direction to particular values (e.g. "forward")
• Seems a bit strange to have cells_in_series specified next to the actual voltage and current values at the IV curve level

Note that the first two items also apply to the json files in pvlib/pvlib-python#1573.

[cwhanse]

Let's also add Serial Number, Model, and rename Sandia ID to Module ID. We can move cells_in_series up into the block with Manufacturer.

I don't know if we could enumerate all the needed values for Sweep direction. Some tracers will go both directions and then combine the values.

[cwhanse]

And add a Description field for the set of IV curves.

[cwhanse]

Consider adding diode_voltage to each IV curve (voltage + series_resistance * current). This may apply for synthetic curves where series_resistance is known, but not for measured curves.