APC SRTL50RMBP1U‑LI 1U Li‑ion External Battery Pack (50 V)
Overview
The APC SRTL50RMBP1U‑LI is an external lithium‑ion battery pack designed for runtime extension of APC Smart‑UPS Ultra on‑line UPS systems. It is deployed by IT engineers and facilities professionals to add high‑density battery capacity where extended ride‑through times are required for critical servers, storage arrays, and networking infrastructure.
This battery pack provides a 50 V DC battery bus constructed with lithium‑ion cells that offer a longer lifecycle (≈ 8–10 years) and reduced replacement frequency compared to traditional VRLA batteries. Li‑ion chemistry also improves energy density and resilience under repeated discharge/charge cycles, lowering overall maintenance costs.
Mechanically compact, the unit occupies 1U of rack height and includes mounting brackets for rack, tower, or two‑post installations, allowing flexible placement in cabinets, remote closets, and small data center aisles. Its design permits chaining multiple packs in series to scale runtime in proportion to load requirements.
The SRTL50RMBP1U‑LI does not convert DC to AC on its own and must be paired with a compatible Smart‑UPS Ultra series UPS to deliver AC backup power. It integrates with the UPS’s battery management and runtime control systems, supporting seamless runtime scaling without interrupting protected services.
Key Features
- 1U rackmount external battery pack for UPS runtime extension
- 50 V lithium‑ion DC battery chemistry
- Rack/tower/two‑post convertible mounting with brackets
- Scalable runtime—chain multiple packs
- Long lifecycle (8–10 years) vs VRLA batteries


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