If a PPA or EPC contract has just handed you an ASTM E2848 capacity test requirement — and nobody on your team has run one before — you have two realistic ways forward: build the capability in-house, or have the test run for you. This page describes the second option: HelioTest's managed capacity testing service, where we execute the full test against your contract's requirements and deliver a report your counterparty can audit.

If you first want to understand what the test itself involves, start with our ASTM E2848 capacity testing guide and come back.

Who a Managed Test Is For

The managed service exists for a specific situation, and it is worth being upfront about it:

  • This is your first contractual capacity test. The requirement showed up in a performance exhibit, the deadline is real, and building regression-analysis capability from scratch for one test makes no sense.
  • You have no in-house analysis capacity. You run projects, crews, or assets — not statistical models. You need the test done correctly, not a new discipline to learn.
  • The result has to hold up. The report will be read by an owner's engineer, a lender's advisor, or an EPC on the other side of a liquidated-damages clause. A number in an email is not going to cut it.

If that is not you — if your team runs several tests a year and has engineers who are comfortable with monitoring data — the self-serve software route is far cheaper per test. Our cost guide compares the two honestly, and the pricing page has the plan details. Not sure which side you fall on? Who can perform an ASTM E2848 capacity test walks through the options with a simple self-assessment.

What the Managed Test Includes

The engagement covers the full test, not just the math:

  • Data review and validation. We check your measured data before anything else: sensor coverage, timestamps, gaps, and whether the dataset can support a valid test at all. If there is a problem, you hear about it before the test runs, not after.
  • Test configuration against your contract. Reporting conditions, regression window, and filtering criteria are set up to match your contract's test exhibit — not generic defaults.
  • Test execution per ASTM E2848. The regression analysis runs on the HelioTest platform, followed by our quality review of the results and data-quality flags.
  • A standardized PDF report. The deliverable states the acceptance criteria explicitly, documents every filtering step with the number of data points removed, and publishes the regression coefficients — the things reviewers actually challenge. Download a sample report to see exactly what you get.
  • The full working files. A data export of the filtered dataset and regression outputs, plus an Excel calculator that independently recomputes the result — so the other side's engineer can verify the arithmetic without trusting a black box.
  • Live platform access. Your test stays accessible as a live project in HelioTest. If the result is borderline or contested, you can see exactly which data points drove it.

What You Provide

Three things, all of which you either have or can request:

  1. Monitoring data access. Measured AC power, plane-of-array irradiance, and ambient temperature as a timeseries (wind speed where available). A CSV export from your monitoring portal works; for SolarEdge and AlsoEnergy systems we can pull the data directly via API.
  2. The plant model. The as-built PVsyst simulation with hourly output — this defines the expected capacity the test measures against. It normally comes from whoever designed the system; if you are not sure you have it, that is a scoping-call question, not a dealbreaker.
  3. The contract's test requirements. The performance exhibit or test protocol section — whatever defines the passing threshold and any prescribed test conditions.

Typical Timeline

  • Scoping call (30 minutes). We review your contract language, your monitoring setup, and your deadline, confirm the test is feasible as specified, and fix scope and price in a quote.
  • Data collection, if needed. The method needs a window of stable, clear-sky operating data — typically at least five to seven days, longer in unfavorable seasons. If your plant has been operating, suitable data may already exist in your monitoring history.
  • Test execution: 3–5 business days. From complete data receipt to final report delivery, depending on data quality and test complexity.

Availability Testing as an Add-On

Many EPC contracts gate substantial completion on two tests, not one: the E2848 capacity test and a contractual availability test. We run availability tests as an add-on to a capacity engagement or standalone — configured to your contract's exact definitions, with the same transparent deliverables. Details on the availability testing page.

How This Differs From Hiring a Traditional Consultant

A consulting firm will run your test competently for $3,000–$5,000+ per site and hand you a PDF. What you typically will not get is visibility: which data points were filtered and why, what the regression actually looked like, whether the method would survive a hostile review.

Because our test runs on the HelioTest platform, the methodology is enforced by software and every step is inspectable — by you and, if it comes to that, by the counterparty's engineer. You also keep the option of running future tests yourself on the same platform, which no consultant offers. The services page has the full comparison and FAQ.

Scope Your Test in 30 Minutes

Bring your contract's test exhibit and whatever monitoring access you have. You will leave the call knowing whether your data supports the test, what the timeline looks like against your deadline, and what it will cost — with no commitment.

Book a scoping call

Prefer to see the deliverable first? Download the sample ASTM E2848 capacity test report — a complete seven-page report, free, no sign-up.