P91 Li lithium UPS comparisons
The P91 Li Series is a standard 2U lithium online double-conversion UPS for distributed IT, network, and industrial infrastructure. It is commonly evaluated against APC, Eaton, and Vertiv platforms when selecting for standardized multi-site rack deployment, long-lifecycle lithium battery performance, online double-conversion protection, and reduced maintenance compared to VRLA systems. This hub also covers the higher-voltage P91g (208–240 V) variant for rack lithium deployments standardized at 208–240 V.
The standard lithium rack platform
Within the Xtreme Power lithium portfolio, the P91 Li is the standard lithium rack UPS for general infrastructure deployment.
| Platform | Role |
|---|---|
| J60C | Short-depth lithium UPS |
| P91 Li | Standard lithium UPS (this platform); P91-1kLi short-depth at 10.6 in |
| J90 | High-density lithium UPS |
| Li90 | Facility-level lithium UPS |
Platform and model comparisons
This page provides both platform-level and model-level comparisons. Platform comparisons evaluate topology, battery architecture, and deployment strategy; model comparisons evaluate specific capacity, runtime, and configuration. Engineers typically begin with platform selection, then evaluate model-level differences based on load and runtime requirements.
Compare by capacity, 1000 to 3000 VA
Start here if you already know the size you need. Each page compares the P91 Li model side by side with the Eaton, Vertiv and APC equivalents: runtime, depth, weight, warranty, TAA and more.
Online lithium at 10.6 in rack depth, against APC, Vertiv and Eaton 1 kVA models. Ships November 2026.
1000 VA lithium UPS comparison →The shallowest and lightest online unit at 1.5 kVA: 15.1 in deep and 25.6 lbs, with a 6-year warranty.
1500 VA lithium UPS comparison →More runtime than the Vertiv at full and half load, a 6-year warranty and TAA compliance as standard.
2000 VA lithium UPS comparison →Full 2700 W on internal battery with the longest full-load runtime, and the lightest of the four at 45.2 lbs.
3000 VA lithium UPS comparison →P91 Li vs APC, Eaton & Vertiv
Direct access to platform and model comparisons supporting specification development, replacement planning, and standardized deployment decisions.
| Category | APC | Eaton | Vertiv |
|---|---|---|---|
| Platform · online lithium | APC Easy UPS SRVSL → | Eaton 9PX Li → | Vertiv GXT5 Li → |
| Platform · line-interactive lithium | APC Smart-UPS SMTL → | — | Vertiv PSI5 Li: by model below |
| 1 kVA · P91-1kLi All three side by side → | APC SMTL750RM2UC → APC SMTL1000RM2UCNC → | — | — |
| 1.5 kVA · P91-1.5kLi All three side by side → | APC SMTL1500RM3UCNC → | Eaton 9PX1500RT-L → | Vertiv GXT5Li-1500LVRT2UXL → Vertiv PSI5-1500RT120LIN → |
| 2 kVA · P91-2kLi All three side by side → | APC SMTL2200RM2UCNC → APC SMTL2K2RM2UCLNC → | Eaton 9PX2000RT-L → | Vertiv GXT5Li-2000LVRT2UXL → Vertiv PSI5-2200RT120LI → |
| 3 kVA · P91-3kLi All three side by side → | APC SMTL3000RM2UCNC → | Eaton 9PX3000RT-L → | Vertiv GXT5Li-3000LVRT2UXL → Vertiv PSI5-3000SRT120LIN → |
| 3 kVA · P91g-3kLi (208–240 V) | — | Eaton 9PX3000GRT-L → | Vertiv GXT5LI-3000IRT2UXL → |
APC comparisons span both platform tiers and all model levels; the 1 kVA row includes both entry-level (P91-1kLi vs SMTL750RM2UC) and matched-capacity (P91-1kLi vs SMTL1000RM2UCNC) options. Eaton (9PX Li) and Vertiv (GXT5 Li) comparisons cover the online-lithium platform and the 1.5, 2, and 3 kVA models. The Vertiv column also compares each size against Vertiv’s line-interactive PSI5 lithium models (PSI5-1500RT120LIN, PSI5-2200RT120LI and PSI5-3000SRT120LIN). The P91g (208–240 V) row adds 3 kVA comparisons against the Eaton 9PX3000GRT-L and Vertiv GXT5LI-3000IRT2UXL. Confirm current competitor specifications against vendor documentation.
Part of a rack-level architecture
UPS platform selection increasingly reflects broader infrastructure strategy — battery lifecycle, thermal design, and power distribution architecture. The P91 Li is commonly deployed as part of a rack-level architecture combining UPS and intelligent power distribution.
Where the P91 Li is deployed
The P91 Li Series is commonly deployed in enterprise server and storage infrastructure, network core and aggregation environments, industrial control and automation systems, and distributed enterprise technology deployments.
For different deployment requirements
Outlet-level switching, denser footprint, and extended-runtime lithium configurations.
J90 comparisons →Compact 1U lithium UPS for shallow racks and space-constrained installs.
J60C comparisons →Three-phase online lithium for facility and higher-capacity infrastructure.
Li90 comparisons →Need help selecting a UPS platform?
Engineers evaluating UPS systems compare lifecycle performance, deployment constraints, and long-term infrastructure strategy. Xtreme Power supports platform selection, deployment planning, and lifecycle optimization.