External-battery rack UPS with scalable runtime

The P91 5–10 kVA combines the UPS module, external battery cabinets, and optional bypass distribution into a single coordinated architecture — simplifying installation and supporting consistent deployment across multiple sites. Built around external battery expansion, runtime is engineered to application requirements rather than fixed internal capacity. Online double-conversion topology continuously conditions incoming power and maintains zero transfer time during outages, supporting both short ride-through and extended-runtime strategies within one platform.

What the P91 5–10 kVA delivers

The scalable-runtime tier

The P91 5–10 kVA operates as the higher-capacity rack UPS tier within distributed power architecture, bridging compact rack UPS systems and facility-level infrastructure. It is typically deployed within equipment racks or electrical rooms, in multi-site infrastructure requiring standardized design, and upstream of rack-level distribution and control.

Choose the P91 5–10 kVA for engineered external-battery runtime and lowest upfront cost; step up to lithium (P91 Li, J90, or facility-level Li90) for reduced maintenance and longer lifecycle, or down to the P91 1–3 kVA for compact per-rack deployments.

VRLA or lithium?

The P91 5–10 kVA is a VRLA-based platform optimized for runtime scalability and predictable lifecycle performance — selected when runtime flexibility and external-battery architecture are prioritized over lithium lifecycle advantages. Lithium platforms such as the P91 Li, J90/J90i, and facility-level Li90 prioritize reduced maintenance and longer lifecycle. Both deliver full-time online conditioning.

Replace legacy 5–10 kVA rack UPS

The P91 is commonly deployed as a replacement for legacy rack-mounted UPS platforms — APC Smart-UPS SRT 5/6/10 kVA, Eaton 9PX 5–10 kVA, and Vertiv Liebert GXT systems — providing a modernization path with scalable runtime architecture, integrated bypass capability, and improved deployment consistency across sites.

P91-5K vs the field at 5 kVA

The differences are clearest at a single capacity. Here is the P91-5K against the 5 kVA online platforms it most often replaces, using the configurations detailed in the per-model comparisons. The 6 and 10 kVA matchups follow the same pattern — full breakdowns are in the comparison hub.

Runtime is at the base shipped configuration; the P91 is an external-battery platform, so its 4U height includes a 2U battery pack. APC and Eaton are more compact at 3U — the P91 leads on usable watts vs APC, full-load runtime vs APC and Eaton, battery warranty, and TAA eligibility. All P91 5–10 kVA comparisons →

Three models, 5–10 kVA

All models deliver unity power factor (kW = kVA). Output is 208 / 220 / 230 / 240 VAC (240/120 V with the optional isolation transformer); capacity derates to 90% at 208 V, and the 6 kVA is reduced by a 30 A input circuit. Batteries are external (see below).

External battery packs

Hot-swappable battery modules; runtime scales with the number of packs (see runtime table).

Runtime by battery pack and load

Estimated runtime in minutes by battery-pack type, pack quantity, and load. The BPXR2U240A (2U) scales to three packs; the BPXR3U240A (3U) scales to eight. The 5, 6, and 10 kW columns are the full-load points for the P91-5K, -6K, and -10K.

Estimated minutes; values vary with battery condition, age, cycles, and ambient temperature. Shaded columns mark each model’s full-load point. For longer runtimes, contact sales or use the UPS selector →

XBDM maintenance bypass and distribution

The optional XBDM module integrates input/output distribution with a maintenance-bypass switch, allowing the UPS to be serviced or replaced without interrupting critical loads — with each output receptacle protected by its own breaker. Variants (XBDM-P91A for 5/6 kVA, and -P91B/-P91C/-P91D) provide L6-30R and C19 outputs, terminal-block, and hardwired options. The XBDM mounts to the rear of a battery pack (adding 5 in of depth) or as a separate 2U rack mount.

Built for critical rack loads

The P91 5–10 kVA is deployed across enterprise IT, telecommunications, industrial automation, broadcast systems, and edge infrastructure — well suited to rack UPS designs where runtime must be tailored to the application while maintaining a consistent platform across sites.

Capacity guidance: 5 kVA for enterprise rack infrastructure; 6 kVA for telecom and industrial systems; 10 kVA for higher-density distributed environments. Runtime is defined by outage duration, redundancy strategy, and lifecycle planning.

P91 5–10 kVA specifications

Documents and related links