UPS Guide

What is a UPS?

An Uninterruptible Power Supply is a device that sits between a power supply (e.g. a wall outlet) and a device (e.g. a computer) to prevent undesired features of the power source (outages, sags, surges, bad harmonics, etc.) from the supply from adversely affecting the performance of the device.

Different Types of UPS Designs

There are three general categories of modern UPS systems are on-line, line interactive or standby/offline.

A standby/offline UPS system

the load is powered directly by the input power and the backup power circuitry is only invoked when the utility power fails. Most UPS systems below 1 kVA are of the line-interactive or standby variety which are usually less expensive.

A line interactive UPS

maintains the inverter in line and redirects the battery’s DC current path from the normal charging mode to supplying current when power is lost.

An on-line UPS

uses a “double conversion” method of accepting AC input, rectifying to DC for passing through the rechargeable battery (or battery strings), then inverting back to 230V AC for powering the protected equipment.

What does a UPS protect us against?

There are three general categories of modern UPS systems are on-line, line interactive or standby/offline.

Power Surges

A sudden increase in power flowing through to your device is typically caused by something like a lightning strike. This leads to a sudden increase in power followed by a drop which causes damage to equipment.


Overvoltage is when the power being supplied is greater than the power required and can cause overheating and damage. Unlike with a power surge, this power is over a sustained period and causes different problems.


Also known as a brown-out, Undervoltage is what occurs when the power supplied is less than is required. This could be from a sudden demand for power in other areas or a problem with the grid, the lack of flow leads to damage and active data loss.

Power Outage

A complete disruption of power, either short or long term. There can be a number of reasons that you might be subject to a power outage but the results can be severe with data loss and system downtime being the major contributors.

By providing a constant flow of power, a UPS allows you to handle these problems as they arise. UPS systems moderate the flow of power and jump in with charged batteries in the event of total disruption.

Battery Lifespan

UPS Warehouse supplies high quality products with various warranty options on our UPS and inverter range. However, battery lifespan / autonomy times are out of our control as noted in our terms and conditions.

With the number cycles and duration of deep discharges which batteries are subject to during load shedding, battery life span and backup times cannot be guaranteed. This is as a result of lack of time between load-shedding events for batteries to fully recharge.

UPS Warehouse is not a manufacturer of batteries but a supplier and as such is subject to the terms and conditions of the manufacturers and suppliers of batteries.

We have received calls regarding battery performance levels. Unfortunately, this issue is across all makes and brands of lead acid batteries.

As the severity of load shedding escalates, batteries are constantly discharging and recharging which in turn affects lifespan.

The cost of running a battery-based power solution is not dissimilar to running a generator, when the fuel runs out, it requires re-filling.

When batteries experience a number of cycles, they require replacement.