M90S-4S Modular UPS – 6–12kW Scalable Single-Phase UPS with N+1 Redundancy
6–12 kW | 208/120V or 240/120V | Modular Online UPS
Modular single-phase UPS platform engineered for centralized power protection, scalable capacity growth, and N+1 redundancy in commercial, industrial, and distributed infrastructure environments.
6–12 kW · 208/120V or 240/120V · Modular Online Double-Conversion UPS · N+1
M90S-4S scalable modular single-phase UPS
The M90S-4S is the scalable tier of the M90S modular family — a 4-slot online double-conversion UPS that grows from 6 kW to 12 kW on single-phase power. It is built for facilities outgrowing rack UPS but still within single-phase infrastructure, using hot-swappable 6 kW power modules and modular batteries for N+1 redundancy and phased growth. Unity output power factor (kVA = kW), a 5.7″ graphic display, integral maintenance bypass, plug-in L14-30P deployment, and configurable output receptacle panels, and a $50,000 load protection policy (USA and Canada). TAA compliant; UL-1778 (TUV) / cUL listed.
Scalable power beyond rack UPS
The M90S-4S introduces true modular scalability within single-phase infrastructure — for facilities where power requirements are growing beyond rack UPS capability but remain single-phase. Built on a 4-slot architecture using 6 kW power modules, it scales from 6 kW to 12 kW and supports N+1 redundancy, runtime expansion, and phased deployment within a single platform. Capacity can be added incrementally as load grows, so UPS sizing aligns to actual requirements while preserving flexibility for future expansion.
What the M90S-4S delivers
Add a hot-swappable 6 kW power module to move from 6 to 12 kW within the same frame — capacity aligns to actual load instead of oversizing or replacing the UPS.
Configure redundant power and battery modules for N+1 within one system, up to 6 kW (one load module plus one redundant) — the availability of multiple UPS without the footprint, wiring, or management overhead. The 12 kW build uses both power slots for capacity and is non-redundant.
Unity PF (kVA = kW) delivers full usable watts with best-in-class efficiency — up to 98% ECO mode — lowering energy cost and heat output, with no need to oversize for a derated power factor.
A factory-installed L14-30P line cord (6 kW) enables deployment without immediate electrical work, and up to two configurable output receptacle panels deliver C19, 5-20R, L6-20R/L6-30R, and L14-30R distribution from the UPS frame.
A 5.7-inch graphic display shows system status and alarms, and each power module carries its own LCD for module-level detail and redundancy state — faster diagnostics and service.
A manual maintenance bypass transfers the critical load to utility power for service without dropping it, and output distribution inside the frame removes external connection components — reducing installation cost.
In the USA and Canada the M90S-4S carries a $50,000 connected-equipment protection policy, covering the load attached to the UPS rather than the UPS alone. Registration is required.
The scalable modular tier
The M90S-4S sits between the entry M90S-2S and the core M90S-6S — a scalable centralized platform for single-phase infrastructure, typically deployed in electrical rooms supporting distributed infrastructure, where multiple separate UPS would otherwise be required, or in facilities transitioning toward a centralized UPS design.
Choose the M90S-4S for single-phase load growing through 6–12 kW with redundancy headroom; step down to the M90S-2S for a fixed 6 kW entry system, up to the M90S-6S for 6–24 kW, or to the hardwired M90S-12S for 6–48 kW.
Modular vs traditional UPS
Traditional fixed-capacity UPS must be oversized up front or replaced as infrastructure grows. A modular platform lets capacity, redundancy, and runtime scale incrementally within one system.
| Modular (M90S-4S) | Traditional UPS | |
|---|---|---|
| Capacity scaling | Add a 6 kW module to 12 kW | Fixed capacity |
| Redundancy | Built-in N+1 | Requires multiple systems |
| Runtime | Modular battery expansion | Less flexible |
| Maintenance | Hot-swap, module-level service | Full-system service |
| Lifecycle | Extend capacity in place | Replace at capacity |
Two capacities in one enclosure
| Model | Capacity | Power modules | Max charge current | Input |
|---|---|---|---|---|
| M90S-4S6K | 6 kVA / 6 kW | 1 × 6 kW | 4 A | L14-30P cord or hardwired |
| M90S-4S12K | 12 kVA / 12 kW | 2 × 6 kW | 8 A | Hardwired (2PH+N+G) |
One 4-slot enclosure (17.4 × 33.7 × 33 in, 130 lbs) holds 2 universal slots (power or battery) plus 2 battery-only slots — a maximum of two 6 kW power modules (12 kW); an optional BC7 cabinet (17.4 × 33.7 × 45.5 in) adds 7 battery slots. For N+1, add one power module beyond the load, so redundancy is available up to 6 kW (one load module plus one redundant); at 12 kW both power slots carry load, so the 12 kW configuration is a maximum-capacity, non-redundant build.
Runtime by load and battery module count
Runtime in minutes by kW configuration and number of installed battery modules, grouped by the battery-cabinet stage required (the 4S enclosure holds 3 internal battery slots in the 6 kW config; each BC7 cabinet adds 7). The stepped line tracks the four-slot enclosure sharing power and battery slots: the internal-battery maximum falls as more power modules are installed (3 modules at 6 kW, 2 at 12 kW), with each BC7 cabinet adding seven slots beyond it. An asterisk marks runtimes that need a second power module to recharge the larger battery bank. At 6 kW that second module is also the N+1 spare, so the long-runtime builds are redundant as well: the extra module carries no load until it is needed, and meanwhile it shortens recharge. A dash means that module count does not apply to the configuration.
| 4S UPS | 4S UPS + 1 BC7 | 4S UPS + 2 BC7 | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Battery modules | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
| 6 kW | 9 | 22 | 35 | 50 | 66 | 82 | 99 | 113 | 124* | 133* | 148* | 163* | 179* | 194* | 209* |
| 12 kW | — | 9 | 15 | 22 | 28 | 35 | 43 | 50 | 58 | 66 | 74 | 82 | 90 | 99 | 106 |
Estimated minutes; values vary with battery age and site conditions. A maximum of eight battery modules is supported per power module; an asterisk (*) marks runtimes that require an additional power module for battery recharge. For longer runtimes or configurations beyond 15 modules, contact Xtreme Power engineering at (800) 582-4524 or sales@xpcc.com.
Rack deployment
The M90S-4S ships as a floor-standing enclosure on casters. Rack mounting requires the M90S-RMK rack mount kit, which carries the enclosure in a standard four-post rack while keeping power and battery modules accessible from the front for service. Order the kit with the system; it is not included. The M90S-RMK manual covers rail spacing and load ratings. Watch a short rack-installation overview:
Where the M90S-4S is deployed
The M90S-4S is deployed across single-phase environments where capacity is growing and redundancy matters — telecommunications infrastructure, network distribution rooms, industrial automation, broadcast environments, and commercial infrastructure — typically where load is expected to grow over time, runtime exceeds rack-UPS capability, multiple separate UPS are becoming difficult to manage, or a three-phase upgrade is not practical.
M90S-4S specifications
| Topology | Modular online double-conversion |
| Capacity | 6 kVA / 6 kW and 12 kVA / 12 kW (unity PF, kVA = kW). N+1 redundancy up to 6 kW (one load module plus one redundant); 12 kW is a maximum-capacity, non-redundant build. |
| Input | 120/208V or 120/240V, 50/60 Hz auto-sensing (2PH+N+G); range 152–269 VAC (L-L), 40–70 Hz |
| Output | 120/208V or 120/240V, 50/60 Hz ±0.1 Hz (2PH+N) |
| Efficiency / THD | Up to 98% ECO mode, 93% online mode; ≤2% (linear), ≤3% (non-linear) |
| Overload | 100–110% for 30 min; 110–130% for 5 min; 130–150% for 10 s; >150% for 200 ms |
| Battery system | Nominal ±96 VDC; max charging 4 A (6 kW) / 8 A (12 kW), adjustable |
| Power module | 16.3 × 24 × 5.2 in, 38 lbs |
| Battery module | 16.3 × 24 × 5.2 in, 107 lbs |
| UPS enclosure | 17.4 × 33.7 × 33 in, 130 lbs; 4 slots (2 universal + 2 battery-only) |
| BC7 battery cabinet | 17.4 × 33.7 × 45.5 in, 162 lbs; 7 additional battery slots |
| Output distribution | Terminal blocks and/or up to two configurable receptacle panels (C19, 5-15/5-20R, L6-20/L6-30R, L14-30R) |
| Options | L14-30P line cord (6 kVA); receptacle panels (2 max); BC7 extended battery cabinet; M90S-RMK rack mount kit; 5-year extended warranty |
| Display | 5.7″ graphic LCD; per-power-module LCD |
| Communications | RS-232, USB, dry contacts, EPO; (2) intelligent slots (Web/SNMP, Relay, Modbus) |
| Environment | 0–40°C (32–104°F); altitude 5,200 ft; audible noise <58 dBA at 1 m |
| Approvals | UL-1778 (TUV), cUL, FCC Class A, RoHS; TAA compliant |
| Warranty | 3 years electronics, 3 years battery (USA and Canada); 1 year outside the USA and Canada; $50,000 load protection policy (USA and Canada) |
M90S-4S: common questions
What is the difference between the M90S-4S and the M90S-2S?
The 2S is a fixed 6 kW system in two slots, with no room for a second power module. The 4S has four slots, two of them universal, so it takes a second 6 kW power module for 12 kW, or keeps one module and uses the spare slot for redundancy or batteries.
Can the M90S-4S run N+1 at 12 kW?
No. Two power modules is the maximum, so at 12 kW both slots carry load and there is no spare. N+1 is available up to 6 kW: one module carries the load and the second stands by. Sites needing redundancy above 6 kW should step up to the M90S-6S.
How much runtime is available, and how is it extended?
At 6 kW, one battery module gives 9 minutes and three internal modules give 35 minutes. Each BC7 cabinet adds seven battery slots, reaching 209 minutes at 15 modules. At 12 kW the same 15 modules give 106 minutes. A maximum of eight battery modules is supported per power module.
Do the longest runtime configurations need a second power module?
Yes, above eight battery modules per power module, and that is an advantage rather than a limitation. At 6 kW the second module is also the N+1 spare: it carries no load until it is needed, and in the meantime it shortens recharge time on the larger battery bank.
Can the M90S-4S be rack mounted?
Yes, with the M90S-RMK rack mount kit, which is ordered separately. The enclosure ships floor-standing on casters; the kit carries it in a standard four-post rack with the power and battery modules still accessible from the front. The M90S-RMK manual covers rail spacing and load ratings, and a short installation video is on this page.
Can it be installed without electrical work?
At 6 kW, yes. A factory-installed L14-30P line cord allows a plug-in installation. The 12 kW configuration is hardwired (2PH+N+G). Output is through terminal blocks, up to two configurable receptacle panels, or both.
What warranty comes with the M90S-4S?
Three years on electronics and three years on the battery in the USA and Canada, and one year outside the USA and Canada, plus a $50,000 connected-equipment load protection policy in the USA and Canada. A five-year extended warranty is available.
Documents and related links
Plan your M90S-4S deployment
Talk to an Xtreme Power specialist about module configuration, N+1 redundancy, runtime sizing with BC7 battery cabinets, receptacle-panel selection, and phased growth from 6 to 12 kW.
