How To Choose The Right Size UPS Battery Backup? – Troubleshooting Guide

If you’re reading this article, you probably already understand the importance of having an uninterruptible power supply (UPS). However, choosing the correct size for your UPS battery backup can be challenging, as your needs are not the same as anyone else’s.

Choosing the right size UPS battery backup is pretty straightforward. Firstly, calculate the total volt-amps (VA) of all your devices and multiply it by 1.2. The answer represents your energy needs plus a little extra to act as a buffer. An ideal UPS size exceeds your total VA needs.

This guide will walk you through each step to choose the right size UPS battery backup for your needs. You’ll also discover a few additional features to look for when shopping for a UPS.

What Do You Consider When Choosing A UPS Size?

Overall, you must consider your volt-amps (VA) requirements before you choose a UPS size. Not only do you need a UPS that can provide your critical devices with the necessary power during a blackout, but it must also be able to run for as long as necessary.

Considering your VA needs is something you should do before shopping for a UPS. Doing that will help you avoid buying a UPS underpowered for your needs.

Here are the steps you can follow to determine your VA needs and help you choose the correct UPS size:

Step 1: List All Devices

First and foremost, list all the devices you want the UPS to protect. Remember: not all devices require backup power during a blackout or other power supply disruption. For example, your speakers don’t need the protection a UPS offers.

Instead, you should focus on your most critical devices, like your computer, server, or backup external hard drive, just to name a few. 

These devices are critical and require UPS protection because a sudden power disruption can cause them damage.

So, list each of them clearly and note their quantities (e.g. some setups have multiple servers).

Read: How Reset APC UPS After Battery Replacement?

Step 2: Calculate The Volt-Amps (VA) For Each Device

Once you’ve identified your critical devices, you’ll need to calculate the volt-amps for each one and add them to the list you started in Step 1.

You can do that by identifying each device’s volts and amps figures. Then,  multiplying the volts and amps will give you that device’s volt-amps (VA).

The volts and amps information is typically displayed on labels stuck on the device. Check behind and underneath it if you can’t find that label.

Alternatively, you might find that the manufacturer lists that information in the user manual, a technical sheet, or that device’s packaging.

Step 3: Multiply VA (If Necessary)

In some cases, you might find yourself with more than one unit of a critical device. Using the earlier example, some users might have multiple server units in a cabinet or rack, all of which are to be protected with a UPS.

So, be sure to multiply the device VA accurately to account for all critical devices.

Read: Why UPS Not Working In AC Mode?

Step 4: Calculate VA Subtotal

At this stage, you’ll be able to calculate the VA subtotal for all the devices you want to protect with a UPS.

Even though that figure represents the power supply needs of all your devices, this isn’t your final step.

Choosing a UPS size based on that subtotal will not be enough. So, there’s one more step you have to take.

Read: APC UPS Battery Not Detected. How To Troubleshoot?

Step 5: Multiply Total By 1.2

Finally, take your VA subtotal and multiply that by 1.2. In doing so, you’re giving yourself an additional 20% buffer which adds up to the ideal UPS battery backup size for your situation.

When you buy a UPS that’s just big enough for your devices, it won’t keep them running for very long. 

Sizing up your UPS a little bit not only ensures that your critical devices will have backup power. But it also ensures that backup power will last long enough for you to shut each device down safely.

Read: UPS Not Working On Generator Power

What Features Are Important In A UPS?

Choosing the right size for your UPS battery should always be your top priority. However, not all UPS models are made the same, even if they have the same battery capacity.

So, here are a few crucial features you should also consider when buying a UPS. 

When you consider these features alongside the UPS battery size, you can choose a model that provides you with the maximum value possible:

• Battery Replacements: All UPS batteries will wear out after 3-5 years. Some UPS models allow you to replace the battery yourself. Others will require the help of a qualified technician. User-replaceable batteries are more convenient if you’re confident about performing the task.
• Indicators And Displays: All UPS models have at least a few indicators, like for Power and Replace Battery. However, other models provide much more information, like those with LCD screens. Models with LCD displays cost more, but they can be more informative when a problem emerges.
• Self-Testing: Many UPS models these days come with various self-testing features. Some will run those features automatically, while others require you to initiate them manually. Either way, self-testing features offer a convenient way of continuously monitoring your UPS health.
• Form factor: The form factor of a UPS refers to its shape and size. UPS units come in many shapes, from desktop units for household use to rack-mounted units for industrial use. A UPS will take up significant space, so you must consider its form factor to suit the environment in which you’ll use it.
• Warranty: An excellent warranty shows the manufacturer’s confidence in the product they’ve sold you. Besides that, it also protects you financially in the case of manufacturing defaults or premature UPS failures. So, consider the warranty you get for the UPS you’re buying.

As you saw earlier, your first consideration when choosing a UPS battery backup should be its size. Still, your UPS is a significant investment on your part. 

That’s why it’s worth taking a bit more time to consider additional features to ensure you get the most from your UPS investment.

Read: Can A UPS Battery Backup Catch Fire?

Frequently Asked Questions (FAQs)

Below are a few frequently asked questions (FAQs) that you’ll find helpful in understanding UPS battery backups and their sizes:

What Is Meant By Volt-Ampere?

Volt-ampere is one of many units used to measure electrical power. It’s commonly used to measure the capacity of an uninterruptible power supply (UPS) unit and determine if it’s sufficient to protect critical devices during a blackout.

How Is UPS Capacity Calculated?

The capacity of a UPS is calculated based on its volt-ampere (VA) rating. The rating is displayed on UPS packaging and in any included printed material. The VA rating is helpful as it helps you determine whether or not a UPS model is enough to provide backup power to your devices.

How Much Power Can A UPS Store?

A UPS will store as much power as its internal batteries can hold. For example, entry-level UPS models can store enough power to run a home PC and its peripheral devices for a few minutes. However, heavy-duty industrial UPS units can also power a whole room full of servers.

How Long Does A UPS Last Without Power?

Two factors determine how long a UPS lasts without incoming power. Firstly, its battery capacity. A model with a higher battery capacity can continue discharging power for much longer. Secondly, the number of devices draining energy from the UPS. The more power-hungry devices are plugged into the UPS, the shorter the UPS will last without power.

How Many Devices Can A UPS Support?

The number of devices a UPS can support depends on how many power outlets it has. Some models will have more outlets than others, despite having the same battery capacity. Remember: the more devices you plug into a UPS, the less runtime it’ll have during a blackout.