UPS Power Backup

Frequently Asked Questions

What is a UPS system?

An uninterruptible power supply provides instantaneous backup power to connected equipment when the mains supply fails or degrades. It bridges the gap between loss of mains and either restoration of supply or a controlled shutdown, and on sites with standby generation it covers the seconds a generator needs to start and take load.

What size UPS do we need?

Sizing means answering two independent questions: how much load must it carry, and for how long. Capacity is limited by both apparent power (kVA) and real power (kW), while runtime is set by battery capacity and is not linear — doubling autonomy requires substantially more than double the battery.

Should we choose online double-conversion or line-interactive?

Online double-conversion isolates the load from mains disturbance completely with effectively zero transfer time, and is the default for control rooms and safety systems. Line-interactive corrects voltage sags and surges without drawing on the battery and suits network cabinets. Match topology to load criticality rather than applying one answer everywhere.

How long do UPS batteries last?

Valve-regulated lead-acid batteries have a typical design life of five to ten years, but real service life is often shorter because life falls sharply with elevated temperature. A battery operated consistently ten degrees above its rated temperature can lose around half its expected life, so battery room cooling matters as much as the battery specification.

Is lithium-ion worth the extra cost?

Often, yes. Lithium-ion offers longer service life, higher energy density, better tolerance of elevated temperature and faster recharge, at a higher upfront cost and with different fire safety and transport considerations. Over a ten to fifteen year horizon the total cost of ownership frequently favours lithium, especially where replacement means shutting down a critical system.

How often should a UPS be tested?

Regularly, and under real load. Most UPS failures are battery failures, and batteries fail silently — a string can look healthy on a front panel and still collapse when called upon. Monitor battery impedance rather than voltage alone, and carry out planned discharge testing rather than discovering capacity during an outage.