How Long Will a UPS Last During a Power Outage

We know how important it is for your business to stay connected and running, despite the unexpected power outages. Comnet Systems Pte Ltd has been committed to helping organisations safeguard their equipment and data through secure, tailor-made solutions for over 30 years.

The question we get asked most is: “How long will the UPS run in a power outage?”. In this section, we will explain the answer by breaking down the key factors that determine UPS runtime and how we can help you choose the right system for your business applications.

Understanding What a UPS Does

A UPS (Uninterruptible Power Supply) is an emergency power system that provides backup power when the main source of power is lost. It gives businesses valuable time to safely power down machinery or keep critical systems online until backup generators kick in.

Unlike generators, which can take time before turning on, uninterruptible power supplies deliver instant protection within milliseconds. For critical infrastructure like data centres, security systems, and communications equipment, this immediate backup is non-negotiable. That’s why businesses choose Comnet Systems for reliable Singapore uninterruptible power supply services– ensuring zero downtime for sensitive operations.

Key Factors That Determine UPS Runtime

The runtime of a UPS during an outage can range from several minutes to hours, based on a variety of factors. When recommending a UPS solution at Comnet Systems, we never forget to consider the following key variables:

1. Battery Capacity

The capacity of a UPS battery, usually in units of VAh (Volt-Ampere hours) or kWh (kilowatt-hours), has the most influence on its capacity to provide power for an extended time.

Bigger batteries = longer time
Batteries with higher voltage or ampere-hour ratings can deliver more stored energy
We supply UPS systems with a variety of battery sizes to accommodate everything from simple office installations right up to large data centres.

2. Connected Load

The entire power your gear is taking from the UPS influences how long it will last. The higher load drains the battery faster.

Example: A 1,500VA UPS will last longer on one server than running multiple pieces of gear simultaneously.

At Comnet Systems, we help customers calculate their power requirements properly so that they do not over-lead and have sufficient runtime.

3. UPS Type

Not all UPS systems are the same. The three most common models are:

• Standby UPS: Suitable for home or small business use; brief runtime
• Line-interactive UPS: Offers better voltage regulation; mid-range runtime
• Online/double-conversion UPS: Suitable for mission-critical applications; longer runtime with no transfer time

As a trusted uninterruptible power supply company in Singapore – Comnet Systems, we provide all three UPS types (Standby, Line-Interactive, and Online) tailored to your operational priorities and budget constraints.

4. Age and Condition of the Battery

UPS batteries drain with age, and older batteries hold less charge.

• Average battery life, 3 to 5 years
• Maintenance keeps the system running reliably
• Replacing aging batteries restores runtime capacity

We offer preventive maintenance and battery replacement so your system is in working order when you need it the most.

5. Environmental Conditions

Heat, humidity, and poor ventilation can reduce UPS battery efficiency. At Comnet Systems, we design UPS arrangements with the environment in mind—especially for server rooms and confined spaces.

How Much Runtime Can You Anticipate?

Estimating Runtime through Calculation

You can even calculate to estimate the UPS runtime. A good formula does magic in the estimation of UPS runtime.

Formula for Estimation

Some UPSs give their battery capacity in Watt-Hours. If the battery rating of yours in the UPS is amp-hours (Ah), convert it to Wh. Amp-hours is the battery charge, and Watt-hours is the power rating out.

Add the wattage of all the devices that are plugged into your UPS system. Then divide the UPS Watt-hour (Wh) rating by the total wattage of the devices to get the runtime in hours.

Examples of Scenarios

For example, if you 1,200Wh UPS battery and you have all your devices totaling 600 Watts, you divide 1,200 by 600, and you get the runtime hours.

1,200Wh ÷ 600Wh = 2 hours.

You can also add the charge capacity of the battery in amp-hour (Ah) by battery voltage (V) for Watt-hour power output. For example, a 12V output 100 Ah battery has a 1,200-watt-hour battery power output.

Why Deal with Comnet Systems?

Although we sell you the equipment, we do not just do that. We design whole systems that satisfy your operational goals.

Our UPS Services Include:

• Site evaluation and load analysis
• Tailor-made system design
• Supply and installation of top UPS manufacturers
• Preventive maintenance and round-the-clock support
• Battery replacement and system upgrades

We service commercial, government, retail, and industrial customers. From one-office UPS arrangements to large-scale data centre backup systems, we have the expertise to do it right the first time.

Real-World Example

We worked with one of our business clients in the logistics sector that was experiencing intermittent brownouts that were ruining network equipment. After a detailed assessment, we installed a line-interactive UPS system with extended runtime modules on their routers and server racks. They have not experienced any hardware failures since installation, and improved operational availability.

Protect Your Business with the Right UPS Solution

For how long will a UPS last during a power outage? This depends on battery capacity, load attached, and configuration of the system. At Comnet Systems Pte Ltd, we help businesses in Singapore choose the right uninterruptible power supplies to protect their business, minimize downtime, and be prepared for the unexpected.

Whether protecting critical devices or entire networks, we are here to provide reliable, efficient, and scalable solutions. Let us help you build peace of mind with uninterrupted power. Contact us today for a tailored UPS consultation that powers and protects your business—no matter what.