PV Capacity Testing Software Built for Engineers

ASTM E2848 is the industry-standard test method for reporting photovoltaic system performance. It defines how to measure, filter, and regress irradiance and power data to determine whether a PV system meets its expected capacity. It is widely used in commissioning, performance guarantees, and ongoing performance assessments for utility-scale and commercial solar projects.

HelioTest supports bifacial capacity testing by accounting for both front and rear-side irradiance contributions. You can configure back-of-module POA sensors and bifacial gain factors so the regression model properly reflects the additional energy harvested from ground-reflected light. Learn more in our guide to bifacial PV capacity testing.

Yes. HelioTest includes built-in GHI-to-POA transposition so you can run a compliant ASTM E2848 test even when plane-of-array sensors are not installed. This is especially useful for sites with multiple array orientations where installing dedicated POA sensors on every sub-array would be cost-prohibitive. See our article on GHI transposition for details.

HelioTest generates a professional PDF report that includes the regression model, expected vs. measured capacity comparison, capacity test ratio, data filtering summary, and scatter plots. The report is formatted for stakeholder review and can be shared with asset owners, EPCs, and independent engineers.

Excel-based workflows are fragile, hard to audit, and require manual steps that introduce errors. HelioTest provides a structured, web-based workflow where site configuration, data upload, analysis, and reporting are integrated into one platform. Every test follows the same repeatable process, making it easier to collaborate across teams and maintain quality across projects. See pricing to get started.

Yes. Alongside ASTM E2848 capacity tests, HelioTest runs contractual availability tests — the inverter uptime demonstration many EPC contracts require at substantial completion, often alongside the capacity test. Because there is no single availability standard, you configure the test to your contract's definitions: the irradiance threshold, the export threshold, how inverter status codes are classified, exclusions such as grid outages, and the guaranteed availability percentage. Deliverables include a PDF report, a minute-by-minute audit table, and an Excel calculator that recomputes the result from the raw data. Learn more about availability testing with HelioTest.

Open-source libraries like pvcaptest give you building blocks for ASTM E2848 analysis, but you still need to write scripts, manage data pipelines, and build your own reports. HelioTest wraps the full test workflow into one platform — from site configuration and data upload through regression analysis and PDF reporting — so your team can run capacity tests without writing code. It also adds features like team collaboration, audit trails, and multi-array support that aren't available in standalone libraries.