Vertiv Liebert APS Modular UPS Systems

The Vertiv Liebert APS modular UPS series

The Vertiv Liebert APS is a single-phase, online double-conversion UPS built for server rooms, enterprise IT closets and row- or room-based edge data centres. Unlike a fixed-capacity UPS, the APS is modular: power is delivered in hot-swappable 5 kVA / 4.5 kW FlexPower modules, and battery capacity is added in matching hot-swappable battery modules. That lets you right-size the system at install and scale it later, a pay-as-you-grow approach, while supporting N+1 redundancy on both power and battery so there is no single point of failure. In Vertiv's lineup it sits above the entry-level GXT online tower/rack units and below the larger three-phase Liebert systems, serving the 5 to 20 kVA single-phase mission-critical band.

Every model in this collection is online double-conversion with a pure sine-wave output and a rack/tower-convertible chassis. The range spans 5 kVA / 4.5 kW up to 20 kVA, scaled in 5 kVA modular increments. North American units provide 208/120 V output: the AS3 / AS4 frames are transformer-based on a 3-wire 208 V input, and the AS5 / AS6 frames take a 4-wire 208/120 V input. Representative models are below; see the full range further down this page.

Runtimes shown are per the product specifications in this collection and vary by installed battery-module count and load. The full set of configurations is listed below.

How to choose

Size by watts, not just VA. A UPS carries two ratings: apparent power (VA / kVA) and real power (W / kW). Your equipment draws real watts, so add up the wattage of everything you intend to protect and choose a model whose wattage rating clears that total with headroom. Each 5 kVA FlexPower module delivers 4.5 kW (0.9 power factor), and the frame's usable watts scale with the number of installed power modules up to 18,000 W, so confirm the W figure on the specific configuration, not only its kVA badge.

Plan for runtime and growth. Runtimes here range from roughly 5 minutes at full load on tightly loaded configurations to over 50 minutes at half load on battery-heavy ones. Because the APS is modular, you can add battery modules to extend runtime and add power modules to add capacity later, buy for today's load and scale toward the 15 kVA or 20 kVA N+1 ceiling as you grow.

Topology and form factor. The entire APS line is online double-conversion, the highest-protection topology: the load always runs off the inverter, with a true pure sine-wave output. There are no line-interactive models in this series. Every unit is rack/tower convertible, so the same hardware mounts in a 19" rack or stands as a tower depending on your space.

Key features

• Online double-conversion topology with pure sine-wave output across the full 5 to 20 kVA range.
• Hot-swappable, modular power and battery modules in 5 kVA / 4.5 kW increments for pay-as-you-grow scaling.
• N+1 redundancy options on both power and battery modules to eliminate single points of failure.
• Rack/tower-convertible chassis to fit racks or floor-standing deployments.
• 208/120 V output (transformer-based AS3 / AS4 frames; AS5 / AS6 on a 4-wire input).
• Pre-installed communication card for remote monitoring.

Warranty, Canadian shipping & support

These are Vertiv Liebert APS systems backed by Vertiv's standard limited warranty: 2 years for VRLA models and 5 years for lithium-ion models, per Vertiv. We stock and ship from Canada. If you need help sizing a configuration for your load, our team can walk you through it before you order.

Already running a Liebert APS and just need cells? See our Vertiv Liebert replacement batteries hub, and browse everything we carry from the brand on the Vertiv collection page.

Frequently asked questions

Is the Liebert APS line-interactive or online? Every model in this series is online double-conversion, the load always runs through the inverter, with a pure sine-wave output.

What capacity range does the APS cover? From 5 kVA / 4.5 kW up to 20 kVA single-phase, added in 5 kVA modular increments, scalable to 15 kVA or 20 kVA with N+1 redundancy depending on the chassis.

Can I rack-mount it or use it as a tower? Both. Every APS unit in this collection is rack/tower convertible.

How much runtime will I get? It depends on load and the number of installed battery modules, configurations in this collection range from about 5 minutes at full load to over 50 minutes at half load. You can add battery modules to extend runtime.

Can I add capacity later? Yes. The modular design lets you add power modules for capacity and battery modules for runtime up to the model's N+1 ceiling, without replacing the whole UPS.

Vertiv UPS systems. We are not an authorized Vertiv dealer and are not affiliated with, sponsored by, or endorsed by Vertiv. Model names and trademarks belong to their respective owners.