When the power goes out at home, it’s an inconvenience, perhaps even a hardship; but a power outage in critical facilities such as hospitals can be a matter of life or death.
Emergency power systems rely on batteries to deliver power at the right moment to start a generator or to run a UPS. Neglected batteries, however, are the most common reason for backup power failure, which is why facility managers use automated battery testing systems to assess battery health.
Low tech, high performance
Batteries are electrochemical energy reactions that begin to expire the moment dioxide paste is factory-applied to their lead grids. The chemical discharge/recharge cycle is continuous, so batteries experience significant degradation over time.
Although batteries are big and heavy and have a relatively short shelf life, they can handle high-surge currents, making them ideal for kicking off backup power systems. Battery management systems help to protect costly emergency backup solutions. In addition, batteries promote a better environment by reducing energy waste.
But problems can arise from the very nature of lead-acid batteries. Unlike most other components within a mechanical system, batteries don’t display outward indications of failure, except in extreme cases. That can make it difficult to determine a battery’s ‘state of health’ and likely lifespan.
Once a battery can produce only 80% of its rated capacity, it’s considered ‘dead’ and should be replaced. However, replacing a battery before its end of service isn’t an ideal strategy; doing so can introduce new risks of manufacturing errors or preventable issues.
Another challenge is that actual performance may fall short of manufacturer specifications — consider today’s smartphones, which may require recharging more often than advertised. Just like smartphones, a backup battery’s condition depends upon usage, operating system and conditions, firmware, and software memory demands, as well as any unforeseen factory imperfections.
Other issues play into battery performance, such as:
- Operating temperature has the most impact on premature battery failure, as high temperatures within battery cells can cause chemical reactions to speed up and accelerate the corrosion rate.
- Grid corrosion can lead to short circuits.
- Undercharging can lead to capacity loss, while overcharging can increase the acid concentration and cause cells to dry out.
- A high temperature condition called ‘thermal runaway’, can cause case meltdown and an exposed battery grid, while ‘top mossing’, which results from a manufacturing defect, can cause self-discharge.
Managing backup battery systems
To address such issues, a reliable battery backup system requires monitoring and management. But operating environments make it difficult to benchmark standard thresholds, and functional assessments are often imprecise.
However, automated systems exist today that are designed to test batteries that run emergency generators or UPS systems. These solutions can combine cranking voltage measurements, operating environment temperatures, and battery age to help provide an inexpensive yet accurate measure of battery health. Such systems help extend battery replacement lifecycles and reduce operating costs.
The most cost-effective approaches are found in energy management or monitoring systems that include automated reports to capture voltage signatures during times of very high current draw (such as during engine start or UPS utility supply loss). These automated reporting systems can help provide practical guidance regarding how to assess and validate battery health, as well as provide data to predict potential instabilities and help develop strategies to prevent such volatility.
Analysis of battery health should be an expected part of any effective healthcare or critical power facility design and energy management plan for uninterrupted power — and peace of mind.