BESS Site Acceptance Test (SAT)

We step in during the final commissioning phase, right before the Commercial Operation Date (COD). 
Your EPC partner handles the physical setup and grid integration, and the manufacturer runs the standard acceptance test on their own work. We add an independent, data-driven check of the warranted performance parameters, AC-side with BASIC and down to rack/string/pack with PRO, plus a review of your warranty contract against good industry practice. Findings arrive while the manufacturer is still on site.

For all utility-scale systems starting at 10 MWh, independent site acceptance test diagnostics are essential.

A battery energy storage system (BESS) is a multi-million-euro capital expenditure (CapEx) investment with strict long-term warranty conditions. Unidentified cell degradation, state of charge (SoC) miscalibrations, and capacity shortfalls before the commercial operation date (COD) can directly jeopardize your long-term return on investment.

Comprehensive volytica SATs account for less than 0.01%–0.1% of total CapEx, making them one of the most cost-effective risk mitigation steps before final EPC sign-off.

A Factory Acceptance Test (FAT) verifies the equipment before it leaves the manufacturing site. A Site Acceptance Test (SAT)  verifies the installed system in its final configuration, on your site, connected to the grid. Both matter, and both share the same blind spot when they are read at plant level only: a drifting sensor or an imbalanced rack passes either way. A finding that nobody rectifies after FAT is still there at commercial operation date (COD).

For our analysis you provide the data your commissioning tests already generate. We work from a shared folder, so no live uplink or telemetry stream is required.

Note: Providing these standard test logs is typically part of your EPC’s standard commissioning scope and should be delivered without additional vendor charges.

Pricing combines a base fee with a capacity-based component, so the price scales with the size of your asset rather than with the number of test days. BASIC starts at €2,900 plus €10 per MWh, PRO at €5,900 plus €30 per MWh. A 250 MWh asset therefore costs €5,400 for BASIC and €13,400 for PRO. Above 1 GWh we quote individually. All prices are net, plus VAT.

Basic Compliance Check:

BASIC is an independent third-party assessment of the warranted key parameters of your BESS at plant level: capacity/SOH and round trip efficiency (RTE), validated AC-side at the point of connection and compared against your warranty contract.
It comes with an expert review of your warranty provisions, including reusable text suggestions for future projects.

PRO Diagnostics (Cell X-Ray):

PRO includes everything in BASIC and adds 100% coverage from the point of connection down to cell issues: bottom-up assessment to rack, string and pack level, exposing hidden manufacturing flaws, latent defects and outliers, plus BMS safety and shutdown logic validation, a SOC estimation audit, and an executive summary with a prioritized action plan. Ordered before December 31, 2026, PRO also includes six months of continuous monitoring after COD.

BASIC tells you whether the plant delivers what your contract promises. PRO tells you where a deviation comes from, what to raise with the manufacturer, and keeps watching the asset into its first months of operation.

Order SAT PRO Diagnostics before December 31, 2026 and we include six months of continuous PRO monitoring after COD at no cost.

The monitoring starts once your data is pushed to volytica's standard APIs. It tracks how the asset behaves through its first months of operation, so a one-time check at handover becomes an ongoing view.

An independent report gives lenders, insurers and technical due diligence teams a third-party record of the asset's condition at handover, rather than documentation from the party that supplied it. It documents which deviations were found before commercial operation date (COD) and what was raised with the manufacturer.

Insurers may also offer better terms (ddiscounts) for BESS assets under continuous battery monitoring, because ongoing data lowers their risk. A one-time SAT does not qualify for this.

PRO includes six months of continuous monitoring to start, which can then be extended, so the SAT is your entry point into a monitored asset.

Whether monitoring affects your specific terms depends on your insurer and your policy.

Yes. BESS warranties often read clearly on paper but are hard to enforce in practice, because terms like operating profile, cycles, degradation limits and evidence requirements are defined inconsistently or too narrowly. Our gap analysis flags where your contract is not technically clear, measurable or verifiable against real battery data, and includes reusable wording you can carry into future procurement. Weak points in one contract become the language that protects the next one.