Forgotten UPS Maintenance… and How It Cost Thousands of Dollars

A UPS that never fails can be the one that poses the highest risk. What typically happens when maintenance is forgotten, sized against real industry benchmarks.

To size the impact of an unmaintained UPS, consider an illustrative scenario based on benchmarks published by Uptime Institute: a mid-sized company with a small data center depends on a 40 kVA UPS that has been operating for six years without documented reviews.

Nobody touches it. Nobody reads its alarms. Nobody tests its real autonomy. One day, during a storm that knocks out grid power for more than an hour, the UPS must hold the load. The batteries, sulfated by years without maintenance, do not respond. The inverter, with a failure that the panel had been flagging for months, does not transfer.

The typical scenario

In a scenario like this, the typical outcome includes: internal service outage lasting several hours, temporary loss of access to ERP and CRM, possible contractual penalty with critical customers, and partial data recovery with errors. The battery is fully sulfated. The inverter has an undetected failure. The audible alarm has been disconnected for months.

The aggregate cost of an event like this — adding up staff time, lost operations, data recovery, and reputational impact — typically ranges between USD $15,000 and $40,000 in a mid-sized corporate environment, per the ranges published by Uptime Institute in its Global Data Center Survey. For larger data centers or those with higher criticality, the figure scales to hundreds of thousands of dollars per hour of downtime.

What went wrong

There was no documented maintenance plan. The battery, with a useful life of 3 to 5 years for VRLA, was never replaced. Nobody reviewed alarms or logs. A transfer test was never performed. The worst error is assuming that, since it never failed, everything is fine. Reality is that degradation accumulates silently until a real failure exposes all the neglect at once.

What TIA-942 says (and what it does not)

The ANSI/TIA-942-C standard (published in May 2024 by TIA TR-42.1) establishes the minimum requirements for electrical, mechanical, and monitoring infrastructure, as well as Tier resilience levels for data centers. What TIA-942 is not: a maintenance procedures manual. The specific preventive maintenance practices are defined in complementary standards: IEEE 1188 for VRLA batteries, NFPA 70B for electrical equipment maintenance, and the guidelines of each UPS manufacturer. What TIA-942 does require is that the infrastructure meets the declared resilience levels; without documented maintenance, that resilience becomes only theoretical capacity on paper.

What changed with lithium batteries

From 2020 onward, UPS units with lithium batteries (mainly LiFePO4) changed the maintenance equation. Useful life went from 3 to 5 years (VRLA) to 10 to 15 years (lithium), with continuous monitoring by BMS (Battery Management System) that reports cell state, temperature, and cycles in real time.

Initial cost is higher, but the TCO (total cost of ownership) over a 10-year horizon is usually lower than VRLA with two bank replacements.

Recommended tests in 2026

Quarterly visual inspection, monthly transfer test, annual autonomy test under load, annual thermography on connections, log reading via BMS or SNMP, and proactive bank replacement when capacity drops below 80 % of nominal.

Lessons learned

A UPS is not an install-and-forget device. Every battery has a finite useful life. Failures do not warn: that is why they are tested under controlled conditions. Preventive maintenance is always cheaper than corrective. The worst error is assuming that, since it never failed, everything is fine.

Sources

[1] TIA — ANSI/TIA-942-C Telecommunications Infrastructure Standard for Data Centers — https://tiaonline.org/product/ansi-tia-942/

[2] IEEE 1188-2005 — Recommended Practice for Maintenance, Testing, and Replacement of Valve-Regulated Lead-Acid Batteries — https://standards.ieee.org/ieee/1188/4776/

[3] NFPA 70B — Recommended Practice for Electrical Equipment Maintenance — https://www.nfpa.org/codes-and-standards/nfpa-70b-standard-development/70b

[4] Vertiv — UPS Lithium-Ion Battery solutions — https://www.vertiv.com/en-us/products/uninterruptible-power-supplies-ups/lithium-ion-ups/

[5] Uptime Institute — Global Data Center Survey 2024 (downtime and maintenance cost benchmarks) — https://datacenter.uptimeinstitute.com/rs/711-RIA-165/images/2024.GlobalDataCenterSurvey.pdf

[6] Wikipedia — Uninterruptible power supply — https://en.wikipedia.org/wiki/Uninterruptible_power_supply