When a business asks for a UPS quotation, the first question is often, “What size UPS do we need?” A more useful starting point may be, “What must remain operational, and for how long?”
A UPS (uninterruptible power supply) helps protect selected equipment when the incoming electricity supply becomes unacceptable or stops. But a rating on the front of a cabinet does not tell you how many minutes your actual equipment will remain powered. Runtime is shaped by the load, battery system, operating conditions and what the business needs to achieve during an interruption.
South Africa’s electricity situation has also changed. Eskom reported on 30 October 2026 that the country had gone 532 consecutive days without scheduled load shedding. That is welcome news, but it is not a guarantee against local faults, equipment failures, voltage disturbances or planned maintenance at a particular site. The business case for standby power is therefore about protecting critical operations, not predicting the next national load-shedding stage.
1. Start with the job, not the UPS catalogue
Ask what happens in the first seconds after the incoming supply fails. Does the business need to keep a server and networking equipment online? Complete a transaction? Protect a production control system? Give employees enough time to save work and shut down safely? Or bridge the interval until a generator is ready to carry the load?
Shutdown, generator bridging and extended battery operation may require different designs.
Define a minimum backup period for genuinely critical loads before considering optional equipment.
2. Understand kVA, kW and actual load
UPS equipment is commonly described in kVA, which relates to apparent power. The useful active power delivered to the load is measured in kW. They are related, but they are not interchangeable without considering the equipment’s power factor and ratings.
More importantly, neither the kVA rating nor the UPS cabinet size tells you the runtime on its own. A supported load closer to the UPS’s usable output capacity will normally exhaust a given battery system sooner than a smaller load. Manufacturer selection tools therefore ask for the protected load and required runtime, rather than treating the UPS rating as a proxy for minutes.
For a meaningful quotation, supply the protected equipment list. A qualified assessor can check actual demand, headroom and manufacturer runtime information.
3. Batteries determine how long the support lasts
The UPS manages the power transition and output, but its battery arrangement determines the available stored energy. Battery type, installed capacity, battery-string configuration and the allowed discharge range all affect how long it can sustain a particular load.
The same kVA rating can come with very different backup times depending on whether a system uses compact internal batteries or a suitable external battery arrangement.
Request a runtime estimate for the specified load rather than a generic minutes figure. It should identify the equipment model, battery configuration and the assumptions behind the figure. Remember that an estimated figure for new batteries is not a guaranteed field result for every installation.
4. Why runtime can deteriorate without an obvious failure
Batteries do not hold their original performance indefinitely. Age, temperature, discharge history and charging conditions influence available capacity. OEM’s note that UPS-displayed runtime is an estimate influenced by load, charge and battery age, and that a battery calibration itself causes additional wear. It should not become a casual routine test.
For lead-acid UPS batteries, high operating temperatures can significantly shorten service life. Battery behaviour and replacement intervals differ by chemistry, model, duty and environment, so published examples should not be treated as one universal replacement schedule.
A system that carried the required load comfortably when commissioned might no longer provide the same margin years later. The right response is a planned professional assessment of battery condition, records, alarms and runtime requirements, not an unplanned deep-discharge experiment on critical equipment.
5. If there is a generator, define the handover
A generator and UPS can complement each other, but they do different jobs. A generator may be chosen for longer-duration supply; a UPS is often used to protect selected loads through an interruption and the generator start and transfer sequence. The specific arrangement depends on electrical design, equipment compatibility and the site.
Confirm the transfer time, equipment that must stay live and the shutdown plan if the generator cannot supply the load.
Define the handover sequence first. JUP Solutions’ published services cover both UPS supply and generator solutions.
6. What a useful site assessment should establish
Before comparing equipment prices, agree on these essentials with the person responsible for the facility:
- Critical loads: Which devices or processes truly require uninterrupted supply?
- Required outcome: Continued operation, generator bridging or orderly shutdown?
- Actual demand: What load is present now, and what may change later?
- Runtime target: How many minutes are needed for the defined outcome?
- Existing equipment: What UPS, generator, switchgear and batteries are already installed?
- Operating environment: Are ambient conditions, ventilation and access appropriate?
- Maintenance position: What inspection, service and battery records are available?
- Commercial constraints: What downtime is acceptable, and who owns operational decisions?
An assessment does not have to begin with a product preference. It should end with a better definition of the problem so the proposed solution can be checked against real operational requirements.
7. Three common mistakes in UPS runtime planning
Mistake one: selecting on kVA alone. This ignores the actual load and battery configuration. A correctly rated UPS can still have too little runtime for the task.
Mistake two: treating a display estimate as a permanent guarantee. Runtime indicators change with conditions and ageing. Manufacturer guidance and appropriate professional verification matter.
Mistake three: assuming every load needs the same backup time. Keeping critical networking online for a transition period is not necessarily the same problem as sustaining a complete production floor. Clear load priorities make quotations more useful.
8. Use maintenance records when planning replacement
If the business already owns a UPS, begin with the most recent service report, battery history, observed alarms and changes in protected equipment. A system may need maintenance, an appropriately sized battery replacement, a load review or a redesigned backup arrangement. None of these outcomes should be presumed before assessment.
JUP Solutions lists preventative maintenance and support among its services, as well as standby battery supply and testing. Those are relevant starting points when an existing system no longer meets its original requirement.
The next question to ask
Instead of asking a supplier, “How many minutes does a 10 kVA UPS give me?”, ask:
“Can you assess our critical load and recommend the backup time needed for the way our business operates?”
That conversation gives your facilities, IT and finance teams a common basis for evaluating options, maintenance priorities and quotations.
Book a Site Assessment with JUP Solutions through the contact page, or call 0800 JUP UPS (587 877). Bring your current UPS model, known load information, battery records and the outcome you need during a supply interruption.
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