| Battery chemistry | Lithium iron phosphate (LFP) is a common choice for stationary home storage because of its thermal stability and long cycle-life potential. | Chemistry affects safety characteristics, usable energy, service life, and operating requirements. | Check the product datasheet for the stated chemistry and confirm that the battery management system is designed for it. |
| Usable capacity | Residential wall-mounted models are commonly offered in modules of roughly 5–15 kWh; available sizes vary by system. | Usable capacity determines how much household load can be supported after accounting for the allowed depth of discharge. | Compare usable capacity—not only nominal capacity—and match it to household consumption and backup needs. |
| Depth of discharge (DoD) | Many systems specify a usable DoD in the region of 80–100%, subject to the manufacturer’s operating limits. | A higher usable fraction can provide more energy from the same nominal battery capacity. | Confirm the permitted DoD, reserve settings, and whether the stated capacity is measured at the battery or system level. |
| Cycle life and capacity retention | Some LFP products advertise several thousand cycles, often under defined test conditions such as specified temperature, DoD, and charge rate. | Cycle-life figures are meaningful only when their test conditions and end-of-life capacity threshold are clear. | Ask for the cycle-test conditions and the guaranteed remaining capacity at the end of the warranty period. |
| Continuous power | Check the continuous charge and discharge power in kilowatts; the appropriate rating depends on the inverter and household loads. | Energy capacity describes how long a battery can supply power, while power rating describes how much it can supply at once. | Verify continuous and peak power ratings, peak duration, and whether the battery and inverter can deliver them together. |
| Round-trip efficiency | A system-level figure around 90% or higher can be a useful comparison point, but results depend on the test method and operating conditions. | Higher efficiency means less energy is lost during charging and discharging. | Compare figures measured on the same basis and check whether they include the inverter and auxiliary consumption. |
| Battery management system (BMS) | A quality BMS monitors cell voltage and temperature and manages overcharge, over-discharge, overcurrent, and temperature protection. | Monitoring and protective controls help keep the battery within its specified operating limits. | Check fault reporting, cell balancing, protective functions, and whether the BMS communicates with the intended inverter. |
| Safety and transport documentation | Look for applicable test documentation, such as GB/T 36276 for stationary lithium-ion batteries, IEC 62619 where applicable, and UN 38.3 transport test evidence. | Standards and test reports provide evidence that relevant safety or transport requirements have been assessed. | Match certificates and reports to the exact model and configuration; confirm the standard’s scope and current applicability. |
| Enclosure protection | For locations where dust or water exposure is possible, an IP rating such as IP65 may be suitable when specified for the complete installed enclosure. | The enclosure rating indicates protection against dust and water under defined test conditions. | Check the exact IP rating and installation instructions; an IP rating does not mean the battery can be submerged or installed outdoors without conditions. |
| Operating temperature | Use the manufacturer’s stated charge, discharge, and storage temperature ranges; these ranges may differ by model. | Temperature affects performance, charging limits, and service life. | Confirm whether temperature control or derating is required for the intended installation location. |
| Inverter and system compatibility | Compatibility should be confirmed for the battery voltage, communication protocol, inverter model, and system configuration. | A battery’s rated performance may not be available if it is paired with an incompatible inverter or control system. | Obtain a written compatibility list and confirm supported communication, firmware, and backup operation. |
| Warranty and service support | Compare warranty duration, throughput or cycle limits, capacity-retention terms, and local service arrangements. | Warranty terms define the conditions under which repair, replacement, or capacity claims may be accepted. | Read exclusions, claim procedures, installation requirements, and the stated end-of-warranty capacity threshold. |
