UPS Servicing - the Forgotten Task
How often should I service the UPS?
One of the most neglected equipment is the backup power supply or UPS. We generally recommend a yearly service to ensure that the UPS is running to specification. However, if the equipment being protected is a critical system such as an emergency phone system etc, then we recommend six monthly services. We perform numerous tests, including a full load test to ensure that the units electronics are working correctly. This also gives us an indication of the condition batteries. Once the test has been completed you get a report indicating the status of the UPS, how long it supported the load, and whether there are any issues with the unit. We also supply a free loan unit when available.
What are the different type of UPS units?
There are three main types of UPS units, however, we only service, maintain and sell two of them. These being the True Online and Line Interactive units
True Online UPS
The true online UPS is the unit we recommend for Servers and important equipment. This is because it doesn't matter what the input voltage is, the output voltage is going to be a stable 230V/240V. This is because the input voltage is converted to DC, and then an inverter recreates the output voltage creating a stable pure sine wave supply.
Line Interactive UPS
This type of UPS takes the input from the supply, stabilises or conditions the power supply and feeds it directly to any equipment connected. When the power drops, the unit then switches over to the battery backup and produces the output power to the connected devices. There is a small delay (<50ms) and quite a 'spike' is noticeable when the switch over occurs. This UPS is the cheaper of the two because it has less electronics.
Why you really SHOULD service your UPS!
Here are just two images of why we recommend you have you UPS equipment tested.
The first image is of a UPS that was situated on the floor picking up dust and storing it internally. This unit was overheating, and could have been a potential fire hazard.
Once a unit has been serviced and repaired this is how the internal electronics should look. We often return to the owner for half the price of a new unit the serviced ups knowing it is safe and will support their equipment during a power outage.
This second image is of a battery pack that failed. As can be seen the terminals of the batteries had corroded, and one of the cells had gone open circuit. Many UPS units will not start if they do not detect a minimum voltage on the batteries, making it difficult to get your equipment online again.
The final image is of some batteries that were removed from some ups units that had suddenly failed without any warnings or notifications. In some cases the whole chassis had to be dismantled to get the batteries out due to the excessive swelling. These batteries in this state can cause serious damage to equipment as can be seen by the batteries at the top of the picture. These were hot enough that they melted their casings.
Five Leading Causes of UPS Battery Failure
Battery failure is the leading culprit behind the majority of UPS catastrophes. But despite batteries’ vulnerability to premature failure, you don’t have to be a victim. At SOHCS, we can test and confirm the operation of your UPS giving you peace of mind that when the power fails or there is a surge, your equipment will be protected.
We’re going to run through the top five causes of premature battery failure and how you can prevent it.
UPS batteries are electro-chemical devices whose ability to store and deliver power slowly depreciates over time. No matter how well you maintain, store and use your batteries, they will still require replacement when they have reached their end of life. Some batteries will last a year, while others will last for more than 5 years. However, there is no way of knowing unless the batteries are tested and checked.
It is generally accepted that the service life of a standard Valve Regulated Lead Acid (VRLA) battery is three to five years. However, there are a number of environmental, chemical and user-related factors that can substantially affect a battery’s life. These are the primary mistakes to avoid to stretch the most life out of your UPS’s battery.
Factors that Cause Premature Battery Failure
Nothing can be done to prevent a battery from eventually reaching its end-of-service life. However, avoiding the following situations can help ensure a maximum lifespan.
- Poor storage of unused batteries– Even as a battery sits unused, its lifetime begins to decrease. That’s because lead-acid batteries automatically discharge small amounts of energy. To prolong a battery’s storage life, we recommend you charge it every three to four months of storage. If you don’t, you could see a permanent loss of capacity in as little as six months. You can also prolong your unused battery’s storage life by storing it at a temperature of 50°F (10°C) or less.
- High ambient temperature– The rated capacity of every battery is based on an ambient temperature of 77°F (25°C). Any variation, but especially increased temperature, can affect performance and lifespan. As a general rule, for every 15°F above the recommended ambient temperature, the expected life of the battery is reduced by 50 percent. Routine maintenance checks can help detect thermal hotspots and verify proper ventilation.
- Over-cycling– After a UPS operates on battery power during a power failure, the battery recharges for future use, an event called the discharge cycle. When a battery is installed, it is at 100 percent of its rated capacity. However, each discharge and subsequent recharge slightly reduces the capacity of the battery.
- Improper float voltage– Every battery manufacturer will specify the charging voltage ranges for their own cell design. If a battery is consistently charged outside of these parameters, it can cause significant damage. Undercharging or low voltage can cause sulfate crystals to form on the battery plates. These crystals will eventually harden and reduce the available capacity of the battery over time. Overcharging with a float voltage that is too high can cause excessive hydrogen and oxygen gases and can lead to internal dryout that, once accelerated, can cause thermal runaway – resulting in failure or even fire and explosion.
- Incorrect battery application– UPS batteries are made specifically for UPSs, just as other batteries are made specifically for their respective appliances. UPS batteries are built to deliver extremely high rates of energy for a short time, generally up to 15 minutes.
Conversely, other batteries, such as telecom and switchgear batteries, are designed to run for longer periods of time, typically between four and eight hours. If a user runs a telecom application with a UPS battery, it will force the battery to run for much longer than its intended purpose. This could cause the battery’s plates to overheat and fail.
The most common failure mode of a VRLA Battery is an open circuit, most often caused by cell dryout. UPS systems typically have a SERIES connected battery system to provide a high current to the UPS System DC Bus. If one cell in a string opens, it will break the current in the entire string. In short, just one failed battery cell can bring down your entire infrastructure.
How Regular UPS Maintenance Checks Prevent Battery Failures
Preventative maintenance includes visual inspection, battery voltage testing, thermal image scans to test for hot or abnormal conditions, and battery terminal connections. If tests show any irregularities, we can determine how critical the situation is and if it makes sense to replace the batteries.
Regular battery service and maintenance is critical in ensuring the reliability of your UPS. Preventative maintenance not only helps connections and removes corrosion, but it can also identify an unhealthy battery before it fails.
You can’t make your UPS battery last forever, but with the proper storage, care and maintenance, you can help increase its longevity, and catch a failing battery before catastrophe strikes