A UPS is only as good as its battery

…so buy VRLA batteries and service them and maintain them for the best results

When load shedding strikes and the only thing protecting your critical load from failure is a UPS, you’ll find out if your batteries are up to the task. The thing is, if they’re not, it’s already too late. 

The consequences of battery failure for your business are far-reaching. Not only will it lead to disruptions in your production, trade, or services, but it can also damage your reputation, cause clients to support your competitors, and lead to financial losses—and in extreme cases, loss of life. If you think I’m being overly dramatic, consider how a power outage at a medical facility with standby power versus one without can be the difference between life and death.

What batteries are best for a UPS?

The best battery for UPS use is a well-maintained Elite VRLA UPS Battery. VLRA stands for valve regulated lead–acid battery, also known as a sealed lead–acid battery. 

Normally, VRLA batteries have a lifespan of 3 to 5 years or 6 to 10 years on float charge, depending on what you buy. In reality, however, this can be reduced if they are not properly maintained, are not kept at the optimum temperature, are not charged correctly, or have been cycled regularly. Every time you discharge a battery, a piece of it gets used up, so when you discharge a battery every day or on a regular basis, it may only last 6 to 18 months before it must be replaced. Some lead acid technologies like lead carbon are high-cycle products that will out-cycle even a lithium battery, and cost much less.

UPS battery maintenance

Regular maintenance and service visits for a UPS include a visual inspection of the batteries, which is essential. Maintenance personnel should look for signs of corrosion, swelling, blockages, leaks, or other damage. 

VRLA battery impedance test

However, you cannot look “inside” a battery—that’s why annual impedance tests are vital. During an impedance test, an alternating current is applied to the battery, and the internal impedance, which is a type of resistance, is measured and recorded in Ohms. The impedance of a cell varies according to the state of charge and cell temperature, so these measurements must be done when the battery is fully charged, and the room ambient is about 20 degrees Celsius. As a battery ages, its internal impedance will increase, and hence it will require a higher charge voltage to stay at top of charge. An impedance test tests each VRLA cell and provides a good indication of the overall condition of the batteries.

Unfortunately, an impedance test alone cannot predict how long your batteries will remain in service. For this reason, it is recommended that you carry out two maintenance visits per year. The first is the impedance test to assess the general condition of the batteries, and the second is a complete discharge test.

VRLA battery discharge test

Discharge tests allow you to evaluate batteries against a simulated load. To perform a complete discharge test, the critical load must be transferred during the assessment. The test results show exactly how and for how long the batteries work. On the plus side, discharge tests simultaneously test the entire installation—batteries, cables, and all connections, to ensure they are working properly.

Unfortunately, not many UPS users perform an annual discharge test on their batteries. There are several reasons why this may be. 

1. Additional maintenance costs.
   On the flip side, the consequences of discovering too late that the batteries cannot carry the critical load in the event of an emergency can cost much more.
2. Concern that draining the batteries will shorten their life.
   VRLA batteries are designed to last around 100 to 300 cycles depending on how deep the battery is discharged, so the annual discharge under test conditions has little to no effect on battery performance in the big picture.
3. There is a small risk that mains will fail during the test, resulting in your critical UPS inverter load being dropped. However, if you ensure your load is turned off before you run the test, downtime will be a minor inconvenience compared to the much greater risk of the UPS not being fully functional in an emergency. Moreover, to mitigate the small risk entirely, you could attach the critical load to an alternative standby power source, like a diesel generator, which will pick up the load if there is a power failure or load shedding during the test.

Doing an impedance and discharge test on batteries every year will help you to ‘know your batteries’. Deterioration and wear and tear can be monitored over time rather than catching you by surprise. You can then make informed decisions about the timing of replacements. Forewarned, you can budget for new batteries and replace yours before they fail. Remember, even the best batteries are consumable and will need to be replaced after X number of years or cycles, whichever happens first. 

The risk of your UPS and its associated batteries failing because they have not been tested thoroughly far outweighs the small risk associated with any system maintenance.

NOTE: It must always be remembered that a battery is a consumable product
used as part of a UPS system.

VRLA Battery service and support

In the end, your UPS is only as good as your batteries. So, invest in the best VRLA batteries and get them checked regularly. In South Africa, with load shedding stage 4 being the new normal, the success of your business depends on it!

Standby Systems has a team of experts to advise you on which UPS systems and batteries are best for your business’s needs. Visit Standby Systems’ website or contact us at 011 794 2541 or  011 794 3406 or WhatsApp 082 450 2361.