Batteries are often the weakest link of any Uninterruptible Power Supply (UPS). Delivering emergency power supply to your electrical load in the case of a power failure, UPS systems allow your systems to keep running long enough for the generator to start or until a proper shut down can occur. They also protect your devices from various electrical issues such as power surges, brownouts, black outs, and power transients. Most UPS systems rely on batteries as their source of power. However, batteries are often prone to failure and can need replacement after a certain amount of time. In this piece, we’ll go over how to tell if a UPS battery needs replacing by outlining some of the warning signs, tips on confirming whether or not a battery is dead, as well as replacement options.

Signs it is time to replace your UPS Battery

Below are a few of the main signs to keep an eye out for when determining if your UPS battery is in need of replacing.

The Low Battery Alarm

Most UPS systems come with a low battery alarm. The machine will run a periodic self-test, only giving an alert signal when a battery replacement is required. Usually, this signal takes the form of an indicator light or alarm sound. If you have a monitoring system set up, you may also receive alerts via email or alternative digital communication.

Poor Amperage or Shorting

When your battery system can no longer supply at least 80 percent of its rated capacity in ampere hours, it is a likely indicator that your battery needs to be replaced. Typically, when the battery reaches this percentage, the aging process will accelerate rapidly, ending the useful life of the battery. This can literally happen overnight.

Unusual Performance Symptoms

When near failure, batteries will often begin to demonstrate strange symptoms you can use to judge the remaining life of your battery. Typically, repeating alarms, flashing panel lights, and strange terminal displays are all symptoms of a failing UPS battery. If your UPS batteries are taking longer to charge, and are self-discharging earlier than usual, it is a definite sign that the battery’s life is nearly over.

Expired Batteries

Every battery manufacturer puts a date code on their batteries, telling you when your battery was made. In most cases, you should expect your UPS batteries to last a maximum of three to five years, but ambient temperature of the room is a sure factor in figuring longevity. Higher temperature equals shorter battery life. While that lifespan can differ depending on the usage requirements of your system and your load, if batteries are nearing this age, it is likely time to consider a replacement.

How to Replace a UPS Battery

When your battery begins to display any of the above warning signals, call your service company to schedule an appointment for service.

Battery Replacement Options

UPS systems are already equipped with VRLA batteries and are typically replaced with similar models. If you are looking for added runtime or redundancy, now would be a good time to discuss options with your service provider. In some cases, you can fit larger amp hour batteries into your current cabinet to lengthen your runtime. However, if you have the space, you can also add a second cabinet for redundancy.

In the end, knowing how to tell if a UPS battery needs replacing can save you a lot of headaches. It's suggested that you have your service company simply replace your UPS batteries with new ones every 3-5 years. This will entail new batteries, new interconnects if needed, hardware torqued to the OEM specifications and battery monitoring devices if necessary. Sometimes you may want the replacement to happen during non-peak hours which can include nights or weekends so make sure they are able to accommodate your schedule. A good Preventive Maintenance routine (1 visit per year) to test and overlook your system would be strongly recommended. Contact Wistex at service@wistexllc.com for additional info or questions.