The Siemens 6EP1935-6ME21 is a sealed lead-acid battery module with 12 cells and a 7 Ah capacity, designed to back up a DC bus in a SITOP UPS system. It's the storage half of the uninterruptible supply — when the mains drop, this module holds the 24 V rail up long enough for a controlled shutdown or to ride through a sag. The 7 Ah rating at 20 °C gives you roughly the runtime you'd expect from that capacity; the real-world number depends on the load current and ambient temperature.
The charging current is capped at 1.75 A, so the UPS charger must be sized to stay under that limit — exceeding it shortens cell life. The temperature-compensated charge voltage is specified from 29 V at -10 °C down to 26.3 V at 50 °C; a fixed-voltage charger will overcharge in summer and undercharge in winter, so this module expects a smart charging algorithm that follows the curve. Service life drops fast with heat: 4 years at 20 °C, 2 years at 30 °C, 1 year at 40 °C, and only 6 months at 50 °C. Mount it away from hot power supplies and drives if you want the full lifespan.
This is an IP00 module — no ingress protection, so it lives inside a clean, dry cabinet, not out on the plant floor near washdown or dust. It mounts to a flat surface using keyhole slots for M4 screws; there's no DIN-rail or S7 rail option, so plan for a dedicated spot on the backplate. The enclosure dimensions are 186 mm wide by 168 mm tall by 121 mm deep, and the mounting width is 206 mm to clear the keyhole hooks. Connections are via screw terminals accepting 0.08 to 4 mm² wire for the positive and negative battery leads.