Vertiv Liebert Nfinity Replacement Batteries

Replacement Batteries for Vertiv Liebert Nfinity UPS Systems

The Liebert Nfinity is a modular, true on-line UPS: 4 kVA power modules and hot-swappable battery modules share one floor-standing frame, scalable from 4 to 16 kVA or 12 to 20 kVA (Liebert brochure SL-23900). Each battery module holds ten 12 V batteries; the kits here use sealed 12V 9Ah AGM/VRLA blocks and cover the 4kVA, 8kVA, 8kVA-XR and 12kVA configurations. When runtime drops or the unit signals a battery fault, those cells are what need replacing. The kits in this collection deliver the correct 12V 9Ah batteries for each Nfinity model so you restore backup runtime without replacing the UPS itself.

Battery type and how it scales

The kits use 12V 9Ah sealed lead-acid (AGM/VRLA) blocks: maintenance-free and spill-proof. Each Nfinity battery module wires its ten 12 V batteries into a 120 V DC string, and the UPS runs several modules in parallel for the runtime each configuration needs. Larger kVA ratings and extended-runtime (XR) configurations simply use more of the same 12V 9Ah cells in additional battery modules. That is why a higher-capacity Nfinity needs a larger battery count, not a different battery chemistry or size.

Identify your unit by exact model

Battery count differs between the 4kVA, 8kVA, 8kVA-XR and 12kVA models, so the safest path is to match by exact model number. Read the nameplate on the front or rear of the UPS (for example, Nfinity-8kVA or Nfinity-12kVA) and choose the kit labelled for that model. The product grid on this page lists the voltage (12V) and capacity (9Ah) for each kit; confirm your model first, then order the matching kit so you receive the right quantity of batteries.

OEM vs aftermarket

Vertiv sells factory battery modules (such as part 200544G2) for the Nfinity line. The kits in this collection are compatible 12V 9Ah AGM batteries matched on voltage, capacity, terminals and connectors, sized for the same module housings and F2 terminals. Choose whichever fits your maintenance policy.

Battery lifespan

Sealed lead-acid UPS batteries typically last 3 to 5 years. Heat is the single biggest factor in how long they actually last: as a rule of thumb, life is roughly halved for every 8 degrees C of sustained operating temperature above 25 degrees C. Keeping the UPS in a cool, ventilated location and replacing cells on a 3-to-5-year cycle keeps runtime predictable.

Replacement steps

The Nfinity is an on-line UPS with hot-swappable battery modules, so batteries can generally be replaced while the unit continues to run on utility power and the remaining modules. Hot-swapping is appropriate for systems designed for it, such as the Nfinity; it is not appropriate for desktop or Back-UPS-class units, which should be powered down before any battery work.

1. Confirm your exact Nfinity model and order the matching kit.
2. Release and slide out the battery module(s) per the unit's instructions.
3. Open the module and note the existing battery layout (orientation and wiring) before removing anything.
4. Replace all cells in the module as a matched set: do not mix old and new batteries.
5. Reconnect using the same F2 terminal layout, reinsert the module, and confirm the UPS clears any battery fault and reports full runtime.

Frequently asked questions

What battery does the Liebert Nfinity use?
Each battery module holds ten 12 V batteries (Liebert); the kits here use 12V 9Ah sealed lead-acid (AGM/VRLA) blocks for the 4kVA, 8kVA, 8kVA-XR and 12kVA models. Larger configurations use more modules.

How do I know which kit to buy?
Match by your exact model number from the UPS nameplate. The product grid shows the voltage and capacity for each kit so you can confirm before ordering.

Can I replace the batteries without shutting down?
The Nfinity uses hot-swappable battery modules, so replacement is generally possible while the unit stays online. Always follow the unit's documented procedure.

Do I have to use Vertiv batteries?
No. Compatible 12V 9Ah AGM batteries matched on voltage, capacity, terminals and connectors fit the same modules and terminals.

How long will the new batteries last?
Typically 3 to 5 years, shorter in hot environments. Plan replacement on that cycle.

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