| Battery Chemistry | Lithium iron phosphate (LFP) is generally preferred for stationary solar storage because of its thermal stability and long cycle life. | Cell specification sheet, safety test reports, material declaration, and battery management system documentation. | 12% | Confirm whether the quoted capacity is usable energy or nominal energy. |
| Usable Energy Capacity | Residential systems commonly range from approximately 5 kWh to 30 kWh per installation; larger commercial systems are modular. | Rated capacity, minimum state of charge, maximum depth of discharge, and usable-energy test conditions. | 10% | Compare usable kWh rather than only the nameplate battery size. |
| Cycle-Life Performance | A competitive LFP product may quote around 5,000 to 8,000 cycles under defined laboratory conditions, often at 80% depth of discharge. | Cycle-test report stating temperature, charge and discharge rate, depth of discharge, end-of-life capacity, and test laboratory. | 12% | Do not compare cycle numbers unless the test conditions are equivalent. |
| Warranty Terms | A written warranty of 5 to 10 years is common for stationary storage, usually subject to energy-throughput or cycle limits. | Signed warranty, throughput limit, retained-capacity threshold, exclusions, replacement process, and claim-response time. | 14% | A longer warranty is not necessarily better if the throughput limit is restrictive. |
| Safety Compliance | The system should have documentation relevant to the destination market, including lithium-battery transport and stationary-battery safety requirements. | Applicable test reports or certificates such as UN 38.3, IEC 62619, IEC 63056, and regional electrical-safety approvals where required. | 16% | Check that certificates match the exact model, cell configuration, and factory entity. |
| Power Output | Residential battery systems often support approximately 3 kW to 10 kW continuous output, depending on module size and inverter configuration. | Continuous power, peak power duration, charge and discharge current, and output derating at high or low temperatures. | 8% | Ensure the battery can meet motor-starting loads and backup-load requirements. |
| Inverter Compatibility | Compatibility should be verified through a published communication protocol, approved inverter list, or completed integration test. | CAN or RS485 protocol map, firmware version, inverter compatibility list, and commissioning procedure. | 10% | Ask who is responsible if communication faults occur after installation. |
| Environmental Protection | Indoor and outdoor models should have a clearly stated enclosure rating; IP65 or higher is commonly requested for outdoor residential units. | Ingress-protection test report, operating-temperature range, humidity limits, corrosion protection, and installation manual. | 6% | Verify performance in the actual climate, especially hot, humid, coastal, or cold regions. |
| Manufacturing Quality Control | The supplier should operate traceable incoming-cell inspection, module testing, end-of-line testing, and serial-number control. | Quality certificates, production-flow chart, sample inspection records, cell traceability policy, and independent factory-audit report. | 8% | Prefer suppliers that can provide consistent records for every production batch. |
| After-Sales and Technical Support | A capable exporter should provide remote troubleshooting, spare-parts support, installation guidance, and a defined RMA process. | Support-service agreement, response-time commitment, troubleshooting manual, spare-parts list, and local service-partner information. | 8% | Evaluate total ownership cost, not only the initial purchase price. |
| Export and Logistics Readiness | The supplier should understand lithium-battery shipping requirements and provide compliant packaging and export documents. | UN 38.3 test summary, safety data sheet, packaging specification, dangerous-goods documentation, HS code, and agreed Incoterms. | 6% | Confirm whether the quoted price includes export packaging, documentation, insurance, and destination delivery. |