Batteries are among the most important components of a UPS platform, and battery failure is a risk you don’t want to run. Just like any other kind of battery, UPS batteries have a finite lifespan and need periodic replacement. 

How will I know if my UPS batteries need replacing?

There are four main ways of understanding whether an individual battery within your UPS platform needs to be replaced. All can be used in combination to minimise battery failure risk:

1.  Lifecycle planning

2.  Panel display

3.  Visual inspection

4.  Testing

Lifecycle planning is where you make some educated assumptions about how long your UPS batteries are supposed to last and replace them before that point. For example, manufacturers will stipulate how long their batteries are intended to last for (e.g. 5 years) in normal site conditions. Assuming your site conditions are normal, replacement should be planned to take place around 70-80% of the way through its expected life – or sooner if site conditions demand it.

Imagine a UPS battery designed to only last one year. If you installed it in January then plan to replace it by early October.

Many UPS platforms will show a UPS battery warning on their panel display when a problem is detected. Depending on the system, this could indicate any number of problems with the battery from damage/leakage to degradation in battery load performance. These will typically need to be replaced.

But this measure – like panel displays – only works if you check it regularly. Some UPS platforms allow you to configure alarms so that the presence of battery defects gets picked up even if you don’t check the panels every day. Integrating your UPS with a DCIM (Datacentre Infrastructure Management) solution can also provide this capability.

Visual inspections are part of good datacentre husbandry, but in the case of batteries goes one stage further than simply walking the aisles and checking panel displays. A regular visual inspection routine will involve removing batteries from the UPS platform and looking for signs of distortion, cracking, leakage and corrosion. Such an approach throws up numerous safety issues and should only be undertaken by a qualified technician using appropriate equipment.

UPS batteries can be very dangerous so doing a detailed inspection is not recommended without physical safety measures in place.

The other obvious drawback is being able to remove batteries without compromising the availability of the UPS i.e. temporarily preventing it from providing power protection in the event of a main power failure. Some datacentre managers are content with running this risk, although best practice would be to deploy multiple UPS platforms/modules for extra redundancy. Some UPS platforms support hot-swappable batteries, so that removal and replacement of each individual battery doesn’t disrupt the capability of the overall system.

Testing UPS batteries is another discipline that requires the kind of skills, equipment and safety protocols best sourced from an external specialist.

The purpose of UPS battery testing is to locate any defects that suggest an earlier-than-planned battery replacement is necessary.

This should include:

  • Battery load (or load bank) testing – where loads are applied to the battery under strict test conditions to observe temperature, current, voltage etc. This will flag up any problems that might occur when the UPS is under maximum stress, which is exactly when you need to count on it!
  • Battery impedance testing – where current is passed through each battery to determine an impedance value. When undertaken periodically, any batteries that fall outside defined parameters (or which are rising in value over two or more tests) are replaced.
  • Battery discharge testing – where battery discharge times are tested against specification to determine effectiveness.

What happens if I don’t replace the batteries?

Ultimately, the entire UPS will fail if you do not ensure that the UPS batteries are working effectively. You might not know this until a critical time when you are relying on the UPS to do its job. The result: unplanned downtime that could last for hours or even days.

The performance of UPS batteries depends on a variety of factors, including:

  1. Time. Every battery has a shelf life and degrades over time because its chemical components can no longer fulfil their potential. This process is accelerated when the batteries are in use.
  2. Datacentre temperature. UPS batteries are designed to work at 24oC (75oF), and this is what most specifications are based upon. Any higher and the anticipated lifespans will start to fall.
  3. Correct Sizing. Just like a car battery, the wrong sized battery for the intended load will spell problems further down the road. Make sure you have the right batteries for your UPS and you are using the right UPS for your required load.
  4. How many times the UPS is used. UPS batteries work on the principle of standing ready to discharge their power in an emergency situation. Actually having to discharge either under test or real conditions slightly diminishes the battery’s capabilities each time you do it. You suffer the same effect with a tablet or smartphone battery.

In rare cases, battery faults can cause the battery materials to become volatile, particularly when heats builds up. UPS batteries that required replacement have been known to explode or leak harmful chemicals.

How often do UPS batteries typically need replacing?

A recommended battery replacement cycle depends on what kind of battery they are, what quality of make, how much load they carry, how often they are discharged, the ambient temperature they operate at, and when they were manufactured.

Batteries from UPS manufacturers like APC by Schneider Electric typically last 3–5 years. Whatever the manufacturer states should be factored in with a safety margin for replacement purposes. For the sake of your critical uptime, it’s better to replace too early than replace too late. Hence, 3-year batteries would typically be replaced after 2¼ years or so. Such replacement cycles normally assume that:

  • Once purchased, batteries are stored for no more that 6–12 months before being installed.
  • Batteries are handled with care (i.e. not dropped, crushed or exposed to moisture/heat).
  • The battery is appropriately sized for the load required.
  • The batteries are used in a datacentre with an ambient temperature not exceeding 24oC and where there is sufficient space for air to circulate.
  • Discharge tests are performed no more than once or twice a year.

Don’t stockpile supplies of UPS batteries as they might degrade before you ever use them. However, it could make sense to keep one or two in reserve in case of emergency, but make sure these never get too old.

Manufacturers typically give minimum 1-year warranties for UPS batteries, but most should last longer than this unless usage or conditions are harsh (in which case, this may invalidate the warranty anyway). Some datacentre managers replace batteries when standard warranties end, but this approach could be overly cautious, expensive and environmentally detrimental. Taking out an extended warranty more in tune with the expected lifespan of the battery might be more advisable for following this approach, though the feasibility of the business case would rest upon the cost of the warranty. 

Are UPS trade-ins a good idea when all I need is a replacement battery?

The replacement of a UPS battery should be a simple and relatively inexpensive affair.  However, manufacturers are keen to encourage UPS users that this could be the opportune moment to consider whether the entire system needs replacing with one that better meets your current and projected power needs. After all, a new UPS platform means new batteries, which means no more worrying about replacing them, at least for several years anyway.

As with every purchase, it comes down to the business case. UPS manufacturers provide attractive discounts in their trade-in schemes, and some of these can be time-limited offers that you need to rush to take advantage of. If you were planning on making a new UPS purchase soon anyway, then why wouldn’t you accelerate the decision now? New UPS platforms benefit from better energy efficiency and utilisation than their legacy counterparts too.

A big part of the decision should be based on your needs for UPS protection and whether these have increased or look likely to increase in the future. 

Most organisations are using more IT, more energy-intensive processors and so on. Certainly a growing business will inevitably need more UPS protection to safeguard a larger datacentre environment. But not all of them are. For some, a big UPS upgrade could be premature. Also, don’t forget that some increases in IT usage that might ordinarily translate into power requirements will be offloaded into the public cloud, should this be part of your IT strategy. Here, the external datacentre environments for IaaS and SaaS instances are no longer part of the remit you have for private cloud, ‘in-house’ infrastructure. 

Can I replace UPS batteries myself?

Most UPS platforms are designed to aid the fast, clean and safe replacement of batteries, even while the UPS platform is in live use (so-called hot swappable components). However these cannot be treated like AAAs in the back of a radio. 

Extensive instructions are always provided and these should be followed to the letter in order to avoid damage to persons, underlying IT infrastructure or the batteries themselves.

Ideally, your UPS infrastructure will be operating in a redundant architecture, meaning you have less risk associated with performing battery replacements and can afford to take time to get it right. Do not hesitate to use a qualified, accredited expert.

Do I need to use the same manufacturer for the batteries and the UPS platform?

When you buy a new UPS platform from your chosen manufacturer, it comes with the required manufacturer-branded batteries ready to go. If you never want to give a moment’s thought to compatibility issues (or entertain the prospect that your datacentre might go offline because you messed around with batteries that the UPS manufacturer doesn’t recommend) then your battery replacement cycle should keep it that way.

However, there is such a thing as ‘off-brand’ UPS batteries and these can be found in all manner of places from eBay to recognised electrical wholesalers. 

Off-brand batteries are not recommended for use by manufacturers, which is a shame because these are often lower in cost and built to the same standards.

The official reason is because, having spent millions on developing their products and checking the quality control of batteries they source, anything less than their recommended battery can’t be guaranteed to perform as well. Failing the use the right batteries could invalidate warranties or leave holes in the maintenance contracts you might agree with your manufacturer. If your UPS fails, someone might point the finger at you for installing a different battery.

How do I dispose of UPS batteries?

The disposal of UPS batteries is legislated for under the Waste Electrical and Electronic Equipment (WEEE) directive in place throughout EU member states. UPS batteries are classified as ‘hazardous waste’ and must be processed according to a strict set of protocols. 

Under no circumstances should you simply ‘throw away’ a UPS battery.

WEEE mandates that the producer of the equipment makes provisions for its collection, recycling and safe disposal. As such, all UPS manufacturers have simple processes in place to allow for this and are required, by law, to provide publicly available guidance i.e. on their websites. They are also required, by law, to offer a free take-back service of any old equipment that they are replacing with new sales. 

In short, send old UPS batteries back to the manufacturer. An accredited installer can also do this for you.