They don’t last forever, but they will last longer and perform better with proactive maintenance

An uninterruptible power supply (UPS) is supposed to ensure that it’s “business as usual” if there’s an unexpected outage. Knowledge is power, as the saying goes. But power – in the form of electricity to run a data center – is money. According to a recent Ponemon Institute study, the average cost of an unplanned data center outage can be more than $750,000, up 38% from 2010.

The UPS minds the power, and everybody sleeps well at night. But, who’s minding the UPS? It turns out that 25% of all outages are caused by UPS system failure. That’s even more than cybercrime or human error, which both are attributed to 22% of outages. It’s definitely time to make sure minding the UPS is your business. Here’s what you should keep on your radar.

UPS batteries

It’s the core of the UPS system. These batteries absolutely must respond and replace the source of electric power until your data center’s generator activates. This is one instance where age has little to do with reliability. Check them regularly – at least on a semiannual basis – to ensure they are in peak condition. Test them for conductance or impedance. Ambient temperature, chemistry, and cycling play a role in the overall life expectancy of the UPS system’s batteries.

Extra-careful organizations sometimes take the proactive step of a battery replacement cycle, and may even have replacements kept on-site. Generally, batteries in a UPS that have been in service for five years or more are at an increased risk of internal component failure. Batteries don’t last forever, and they’re not more reliable just because the UPS system is constantly recharging them.


UPS systems often have dozens of capacitors, each with a specific role in helping to filter or smooth out electrical current fluctuations. They aren’t batteries, but they are designed to store and release electrical energy. And like batteries, they will degrade over time. This happens when the tissues soaked in electrolyte inside the capacitor begin to dry out.

Here’s the thing about a capacitor failure: You won’t know it if one fails. The other capacitors will assume the workload, and it’ll shorten their life span. That’s bad news, but there’s even worse. A failed capacitor may trigger your UPS to switch to bypass mode. The power stream bypasses the filtering electronics. Your UPS is operational, but it’s not protecting downstream equipment.

Keep the Arrhenius equation for chemical activity in mind if you want to take a proactive approach to prolong the life span of UPS capacitors. It applies to batteries, as well. You’ll double the life of an electrolytic capacitor with a 10-degree Celsius reduction in data center temperature.

The UPS manufacturer will provide you with a recommended replacement schedule.

Cooling fans

They cool the UPS when it’s in operation. Most UPS systems operating in data centers have more than one fan, but even a single failure can allow a temperature increase that will cause the UPS to overheat.

These fans aren’t really all that high-tech. They are just fans, after all. Malfunctions can be caused by something as simple as dried-out ball bearings. The best way to prolong the life of a UPS fan is to reduce the reason for operation. Temperature isn’t the only reason a fan will activate. The UPS system can activate the fans when the load attached to it surpasses a predetermined operating capacity threshold.


One of the least expensive preventative measures you can take is a regular inspection of UPS air filters. Your data center will likely have its own air filtering system. Air pollution continues to be a problem in many major metropolitan areas. Even so, dust or any particulate matter that blocks the UPS air filters will decrease airflow when it’s in use. Give them a monthly checkup.

Metal oxide varistors

We often think of UPS as the hero that keeps the juice flowing when the power dies, but it also is designed to take a hit if there’s an extreme voltage spike. The metal oxide varistors (MOVs) absorb this excess voltage, and sufficiently large zap might be enough to destroy them. This UPS component should be examined regularly.

You can’t afford the downtime

A 2018 report by the U.S. Energy Administration shows that the average American experienced an average of 1.3 interruptions and went without power for four hours during 2016. You may have a higher feeling of confidence because of the UPS on the premises, but it can only offer protection as good as the protection it gets. Maximize your investment by being proactive about preventative maintenance. You’ll get longer life and better performance.

If you have a UPS that’s more than five years old, it’s likely that your power requirements have increased in the meantime. It’s also likely that a new UPS will offer extensive improvements in protection. We can help you upgrade.