SKU vs Component Characterization

The HelioScope component database has two levels for defining each component: the Product SKU, and the Characterization:

  • Product SKU: The product SKU typically corresponds to a manufacturer’s part number. The SKU has the form factor and high-level specifications of the product. For example, with a PV module, the SKU includes the dimensions and weight, and the overall STC values of voltage & current.
  • Characterization: The characterization is the math behind the module or inverter. The characterization defines the exact physics of the object. For example, a PAN file is one example of a characterization for a PV module.

Use in HelioScope

In the Designer of HelioScope, the user generates a system design by defining SKUs for modules and inverters. Then separately, as part of the Condition Set, the Characterizations for each SKU are selected (or default values are used).


Each SKU is associated with at least one characterization, though the SKU can also have multiple characterizations. For example, this could be due to:

  • Different versions of mathematics (PAN versus single-diode for modules)
  • Slight changes to the product over time
  • Characterizations from different sources (e.g. from the manufacturer, versus from a third-party test lab)
  • Private / proprietary characterizations that are only visible to one user or company

Benefits of the Structure

  • Streamlines the Design process, as the user can focus on the products to use (which is the relevant procurement decision), and then separately can think about which characterization to use for the mathematics behind the module/inverter
  • Enables the user to compare different Characterizations easily, by creating different Condition Sets
  • Minimizes database clutter, since multiple characterizations can be added to a single product SKUs
  • Give the manufacturer some control over the database, as they can add new characterizations, and change the global defaults for characterizations

In Practice

This screenshot from the HelioScope module database illustrates the relationship between a SKU and its three Characterizations.