M90S-6S (18 kW) vs Vertiv Liebert APS AS6C0NCWGNNXLKB
The Xtreme Power M90S-6S, configured for 18 kW usable output, and the Vertiv Liebert APS AS6C0NCWGNNXLKB are modular online double-conversion UPS for mission-critical IT, network, and edge-infrastructure loads. Both support modular growth and hot-swappable components; the M90S-6S delivers full 18 kW as a base configuration, longer baseline runtime, and integrated service features, whereas the Vertiv APS reaches 18 kW only at its maximum scaled configuration.
Where the M90S-6S leads at 18 kW
- Full 18 kW (unity PF) at base configuration vs the Vertiv’s 15 kVA / 13.5 kW base.
- Greater long-term growth headroom — scales to 24 kVA / 24 kW vs 20 kVA / 18 kW (N+1).
- Longer baseline internal runtime (about 9 min vs 5 min), reducing reliance on external battery modules.
- Integrated maintenance bypass, module-level diagnostics, TAA compliance, and a 3-year warranty.
18 kW modular UPS, side by side
| Specification | Xtreme Power M90S-6S | Vertiv Liebert APS AS6C0NCWGNNXLKB | Advantage |
|---|---|---|---|
| Base configuration rating | 18 kVA / 18 kW (unity PF) | 15 kVA / 13.5 kW | Higher usable power out of the box |
| Maximum scalable rating | Scales to 24 kVA / 24 kW | Scales to 20 kVA / 18 kW (N+1) | Greater long-term growth headroom |
| Topology | Online double-conversion | Online double-conversion | Equivalent protection |
| Internal runtime (full load, base) | About 9 min @ 18 kW | About 5 min @ full load | Longer baseline runtime without EBMs |
| Maintenance bypass | Standard, integrated | External maintenance bypass option | Reduced accessories and installation cost |
| Display & diagnostics | Chassis LCD + module-level displays | Removable chassis LCD | More granular local visibility |
| Certifications | UL, cUL, TAA compliant | UL, cUL | TAA compliance for regulated markets |
| Warranty | 3 years (electronics & batteries) | 2-year limited | Longer standard coverage |
Capacity figures show usable watts: the M90S delivers unity power factor (kVA = kW), while the Vertiv APS is rated at a lower power factor. The M90S is UL / cUL listed and TAA compliant; the Vertiv APS is UL / cUL. Runtime figures are base-battery, full-load estimates from manufacturer documentation.
Choosing between them
Both are modular online double-conversion UPS. The M90S leads on unity-PF usable kW, longer baseline runtime, scalability headroom, integrated bypass, module-level diagnostics, TAA compliance, and warranty; the Vertiv APS fits where it is already the standard or where the load sits at or below its usable rating.
Choose the M90S-6S if you need
- Full 18 kW usable output at base configuration
- Longer runtime with base batteries
- Expansion headroom beyond 20 kVA within one platform
- Integrated maintenance bypass to simplify installation
- TAA-compliant solutions for regulated environments
The Liebert APS AS6C0NCWGNNXLKB may fit if you need
- Alignment with an existing Vertiv APS ecosystem
- A solution designed to scale up to 18 kW over time
- External bypass as part of a predefined architecture
Related comparisons
Replacing a Symmetra LX or planning modular UPS?
Xtreme Power supports modular UPS sizing, N+1 redundancy planning, and smooth migration from legacy Symmetra LX systems across enterprise, healthcare, industrial, and public-sector infrastructure.