Factory acceptance
C&I ESS FAT factory inspection before shipment.
Connect ordered configuration, serial records, communication, alarms, E-stop, startup and shipment condition to final payment.
A factory acceptance test gives the buyer evidence that the exact cabinet or container was checked before shipment. It should connect serial numbers, battery racks, PCS model, EMS version, alarm behavior and packing documents.
Use this checklist with the supplier qualification page and the relevant BESS container or cabinet page.
FAT should match the ordered system
A generic certificate is not enough for a project buyer. The FAT evidence should show the actual configuration, not only a standard test template. Photo or video evidence is useful when remote inspection is required.
FAT checklist
| Check item | What to request | Why it matters |
|---|---|---|
| Battery checks | Voltage, insulation, BMS status and module/rack records. | Confirms battery build and protection status. |
| PCS startup | PCS model, startup process, grid mode and power settings. | Confirms power conversion scope. |
| EMS display | SOC, alarms, control screen and communication status. | Confirms system visibility. |
| Safety checks | Emergency stop, fire alarm interface and warning labels. | Supports installation safety review. |
| Shipment evidence | Serial-number photos, packing photos, label and document list. | Connects tested system with delivered goods. |
Before final payment
Ask for FAT evidence before balance payment when possible. For site requirements, compare the site survey checklist and PCS sizing guide.
What a useful FAT record should prove
A useful FAT record proves that the ordered system was inspected, powered and checked before shipment. It should identify the cabinet or container, battery racks, PCS model, EMS interface, alarm behavior and key safety checks. If the record cannot be connected to the shipped system, its value is limited.
For remote buyers, photos and short videos can be practical evidence. They should show serial numbers, cabinet or container exterior, internal layout, display screens, alarm tests, packing condition and labels. This is especially useful when the buyer cannot visit the factory.
FAT should also expose missing responsibility. If the PCS is not powered during FAT, ask why. If EMS screens are not shown, ask who completes commissioning. If fire system documents are missing, ask whether they are supplied by another party.
How FAT evidence supports warranty
Warranty disputes often depend on operating evidence. A good FAT record gives a baseline before shipment. After installation, maintenance logs, alarm records and site conditions can be compared against that baseline to understand whether the issue comes from manufacturing, transport, installation or operation.
Quotation review notes for FAT evidence
The quotation should state whether FAT is included, what will be tested and what evidence the buyer receives before shipment. If FAT is optional, the buyer should know the price, schedule and evidence format before final payment.
FAT evidence should be tied to the actual cabinet or container, not only to a product family. Ask for serial-number references, photos, screenshots, packing records and a signed or exported checklist where possible.
| Quote item | Question to ask | Risk if unclear |
|---|---|---|
| Included scope | Which battery, PCS, EMS, cooling, fire and document items are included? | The buyer may compare a complete system with a partial supply. |
| Responsibility | Who supports setup, troubleshooting, spare parts and warranty claims? | Problems can move between supplier, integrator and installer. |
| Evidence timing | Which documents are available before deposit, before shipment and after commissioning? | Important evidence may arrive too late to influence the purchase decision. |
FAQ
Is FAT required for every project?
For C&I systems it is strongly recommended, especially for cabinets and containers.
Can FAT be done remotely?
Often yes, with structured photos, videos and signed records.
What is the most important FAT item?
BMS communication, PCS startup, EMS display and safety alarms are usually key.
Should FAT include serial numbers?
Yes. This connects the tested system with shipment evidence.
Can FAT reveal missing scope?
Yes. It often exposes unclear PCS, EMS, alarm or document responsibilities.
Configuration-specific FAT
Tie the FAT procedure to the selected platform.
The witness plan should test the interfaces that make each configuration different, not only repeat a generic battery inspection.
| Platform | FAT emphasis |
|---|---|
| 105–250 kW C&I cabinets | Integrated PCS/BMS/EMS, 400 V output, liquid cooling and fire interfaces |
| Container BESS | Battery strings, DC collection, PCS step-up, MV boundary and container auxiliaries |
| 100/233 hybrid | PCS, DCDC/MPPT, 200 kW STS, generator interface and source-priority logic |
| 219.24 kWh sodium-ion DC | 216–504 Vdc window, UPS interface, alarms, DC breaker and discharge record |
| All platforms | Model/serial identity, communications, E-stop, detection/suppression, packing and documents |
Related buyer guides
Continue with the next engineering decision.
Use the guide that matches the open sizing, electrical, safety or quotation question.
BESS fire protection documents
Check design basis, detection, suppression, alarms, emergency stop and FAT evidence.
Read guideCommercial battery storage cost
Separate battery, PCS, enclosure, electrical BOS, delivery and commissioning cost drivers.
Read guide400 V vs 690 V BESS
Review current, cable, switchgear, transformer and AC interface implications.
Read guideContinue the project review
Connect the next decision.
Use the related page that matches the next equipment, engineering or evidence question.
Bring the site data. Leave with a clearer BESS scope.
Share the load profile, grid voltage, target kW and kWh, installation country, ambient conditions and expected schedule.