A Quick Guide to UPS System Battery Maintenance and Monitoring

Commentary contributed by Rob Hirschberg, Head of Marketing and Ken Wright, Technical Telecom Manager with  Alpine Power Systems

Every UPS (uninterruptible power supply) system has a battery that initiates when loss of power from the main-source is identified. The battery is the life behind every UPS system. The UPS battery acts as a secondary power source that allows data to be saved in the event of a commercial power outage.  Unfortunately, the battery is the weakest link in every UPS system.  UPS batteries should be properly maintained and monitored to prolong their life, mitigate safety concerns, and most importantly, avoid downtime. Follow this simple guide below to learn the importance of battery maintenance and monitoring and understand how to perform these tasks effectively.

Monitor UPS Batteries for Effective Emergency Back-Up
An UPS is a device that allows computers or computing devices to keep running during a commercial power outage.  It also protects said devices from power surges. This battery acts as a secondary power source and allows computer data to be saved before the battery is completely discharged. UPS batteries must be properly maintained and monitored to assure that the UPS will work as designed when needed. Routine inspections and testing as well as battery monitoring devices can be utilized as part of a proper maintenance program. Just one underperforming cell will compromise the entire battery and can severely reduce UPS back up time or worse.

UPS Placement, Temperature and Environment
The environment around the UPS plays an important role in battery performance and life expectancy. Batteries cannot function properly in temperatures that are too hot or too cold.  The temperature recommendation from the battery manufacturer should be followed stringently. Most UPS batteries designed to operate at an ambient temperature of 77°F.  If a battery is operated at higher temperatures, its usable life will be shortened significantly.  Too cold and the batteries performance will be decreased. New technologies such as lithium-ion and TPPL can operate at higher/ lower temperatures but most UPS batteries are conventional Flooded or VRLA and are designed for 77°F.

It is also important to note that the UPS should not be placed near open windows, corrosive fumes, dust, or anywhere with moisture.

Determining Battery Life Expectancy
Most UPS batteries do not last as long as the battery manufacturer suggests.  Many factors play a role in battery life.  UPS battery do more than just provide power during a power outage.  They are constantly called upon for line conditioning. This means that regardless of the quality of your commercial power service, computers, servers and data will always receive clean pure A/C power. UPS batteries may be called upon many times per day, this is known as cycling.  A cycling monitor attached to your UPS battery can be a valuable tool in predicting “end of life”. Using a cycling monitor for UPS batteries will allow data center staff to plan for battery replacements before it’s too late, therefore avoiding costly downtime.

Maintain UPS Batteries’ Float Voltage Through Regular Maintenance
Another crucial item in battery performance is float voltage.  The battery manufacturer provides the proper float voltage, usually 2.25 to 2.27 volts per cell.  The battery’s voltage should be routinely monitored and adjusted as needed.  Over charging a battery will lead to premature failure, undercharging will reduce its performance and can also cause premature failure.

UPS Battery Maintenance
“Maintenance-free” UPS batteries do not require replacement fluid, but they do require periodic maintenance. Battery service and maintenance are essential to ensuring ongoing UPS reliability. Without it, a UPS battery becomes susceptible to a number of threats that can ultimately result in a reduced level of protection and premature failure. Visually inspect batteries for cleanliness and remove any dust, dirt, or debris. Leaking batteries or batteries with excessive swelling are a sign of “end of life” and should be properly disposed of and replaced.

Proper maintenance allows the end of battery life to be accurately estimated, enabling scheduled replacement without unexpected downtime or loss of backup power. In addition, preventive maintenance helps extend the life of battery strings, providing the opportunity to detect loose connections, remove corrosion and isolate bad batteries before they affect the entire string. Finally, gradual decreases in battery life can be monitored and evaluated through periodic voltage assessments and load testing completed during a PM visit.

During regularly scheduled PM visits, trained technicians should perform a number of inspections, including visually scrutinizing batteries, racks or cabinets for signs of corrosion and leakage; measuring the float voltage and current of the entire bank; recording the terminal voltage of all cells; checking the electrolyte levels and specific gravity readings in each cell (for flooded batteries only); noting the ambient temperature; conductance or impedance readings should be taken from every cell and compared to the manufacturer’s published values.  All readings should be archived for comparison with future readings.

IEEE Standards: UPS Battery Maintenance, Monitoring and Testing
The Institute for Electrical and Electronics Engineers (IEEE) is widely accepted as offering the best standards-driven recommendations to those responsible for battery maintenance procedures. IEEE guidance encompasses inspections, measurements and capacity tests. Refer to the following standards for more information regarding battery maintenance: IEEE 450 for vented lead-acid batteries (VLA), IEEE 1188 for valve-regulated lead-acid batteries (VRLA), and IEEE 1106 for nickel-cadmium batteries (NiCad).

Battery Storage
To avoid the consequences of downtime, many UPS owners may purchase replacement batteries before they’re needed. Traditional lead acid batteries MUST be charged every six months or they will suffer a permanent loss of capacity.  The battery manufacturer will provide the proper charging sequence.  Proper charging procedures must be followed to ensure the battery warranty remains valid.

Supplemental Battery Monitoring Technology
Remote battery monitoring technology is available from a variety of manufacturers that can assist a technician with routine maintenance. These systems can send notifications when alarm thresholds are reached. Systems can monitor float voltage, cell voltage, electrolyte levels, internal conductance/ resistance and more.  While remote technology cannot replace the need for routine visits, it is an additional tool that can help assure maximum protection (up time) and predict battery end-of life.

• 450-2010 – IEEE Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-Acid Batteries for Stationary Applications

• 1188a-2014 – IEEE Recommended Practice for Maintenance, Testing, and Replacement of Valve-Regulated Lead-Acid (VRLA) Batteries for Stationary Applications – Amendment 1: Updated VRLA Maintenance Considerations

Rob Hirschberg is the Head of Marketing at Alpine Power Systems, a leader in backup power solutions for Fortune 1000 companies. Alpine has been providing dynamic offerings to our global customer base for 55 years starting in 1963. Rob is a graduate from Michigan State University.

Ken Wright is a Technical Telecom Manager at Alpine Power Systems specializing in DC power system sales for telecommunications applications. Ken has more than 25 years in the backup power solutions industry.

For more information, visit Alpine Power Systems.