How long can a 10 kWh rack battery run a small server room?

Direct answer: Runtime is roughly usable battery energy × inverter efficiency ÷ load. A 10.24 kWh pack feeding a 1.5 kW load, with 80% usable energy and 92% inverter efficiency (both assumptions), runs about 5 hours. Check the load against the pack’s 100A limit, and remember a battery alone is not a UPS.

Start from the published figures. The PM-LV51200-5U is listed at 51.2V, 200Ah and 10.24 kWh, with 100A maximum continuous discharge, RS485 and CAN bus communication and an IP21 rating, which means dry indoor use. At 51.2V nominal, 100A is about 5.1 kW, a ceiling on the load the battery can feed before inverter limits apply.

Usable energy is less than nominal. The pages quote cycle life at 80% DOD, but how much of the capacity your inverter and BMS actually allow depends on their settings, so ask Redway to confirm the window. Inverters also lose energy. Example, with assumptions rather than Redway data: 10.24 kWh × 0.80 × 0.92 is about 7.5 kWh deliverable. A measured 1.5 kW load then runs about 7.5 ÷ 1.5 = 5 hours, and a 3 kW load about 2.5 hours.

Measure the load instead of adding nameplates. Equipment usually draws less than its label most of the time, but start-up and fan ramp-up can spike. Use a plug-in power meter or the readout on your UPS or PDU over a typical week, and note both the average and the peak. Include the router, switch, cooling and lighting you want during an outage. Inverter sizing also depends on power factor, so check kVA as well as kW.

A battery is not a UPS. Backup needs an inverter or UPS that switches over fast enough for your equipment. The rack modules contain no inverter. The PowerAll all-in-one page lists an automatic switch time under 10 ms in UPS mode, but that is a different product. If the servers cannot tolerate any break, specify an online UPS and ask Redway how the battery should connect to it.

Check physical fit and test the result. The PM-LV51200-5U is 570 × 440 × 222 mm and about 77 kg, so confirm rack depth and shelf rating. After commissioning, run a controlled discharge with the real load and record the time to the inverter’s low-battery cut-off. If you plan more than one module, read our post on paralleling PM-LV rack batteries of mixed age. The usable-energy window and inverter pairing are not published on the product page, so confirm both with Redway.