How do you commission a new bank of parallel PM-LV rack batteries, step by step?

Direct answer: Treat commissioning as a checklist: confirm all modules are the same model and firmware, bring them to a similar voltage before paralleling, set the DIP addresses, connect power cables of equal length to a common busbar, connect communication cables, power up in the order the manual gives, confirm the inverter sees every module, then set and verify the charge limits. Record baseline readings for later comparison.

Before you start. Check that every module is the same model and, if possible, the same firmware. The PM-LV51100-3U (51.2V, 58.4V maximum, 40V cut-off) and the PM-LV48100-3U (48V, 54.75V maximum, 37.5V cut-off) have different voltage windows and must not share a bank. The 3U pages list up to 64 modules in parallel; the PM-LV51200-5U lists 16 to 32. This post covers new banks; mixing ages is covered in paralleling mixed-age modules.

Step 1: equalise. Measure each module’s voltage with breakers off. If they differ, charge them to a similar level one at a time before connecting them together, so large balancing currents do not flow between modules at switch-on. Ask Redway what voltage difference is acceptable.

Step 2: address. Set the master and slave addresses on the DIP switches as the manual’s table shows, with the master normally the module connected to the inverter.

Step 3: power cables. With all breakers off, connect each module to the busbar with cables of equal length and cross-section, so current shares evenly. Size the bank cable and its DC overcurrent protection for the inverter’s maximum DC current, following the electrical code that applies (NFPA 70 in the United States). Torque terminals to the specified values.

Step 4: communication. Link modules with the parallel communication cables, then connect the master to the inverter using the correct port and pinout; see connecting to a hybrid inverter.

Step 5: power up and verify. Switch on in the manual’s order, check that each display shows no alarm, and confirm the inverter reads the expected module count and capacity. Set charge voltage and current limits within the battery’s ratings.

Step 6: record. Note each module’s serial number, voltage, state of charge, firmware, DIP setting and terminal torque. These baselines make later faults much easier to diagnose.