Strengthen UPS systems with informed maintenance.
By Jeff Donato
When a blackout engulfed much of the northeastern United
States in August 2003, many facility managers learned the
hard way whether or not their uninterruptible power supply
(UPS) systems could deliver as promised. Millions of dollars
invested in security and peace of mind failed, and the biggest
question was why UPS systems didn't work as expected. The
answer in many cases was the system's batteries.
Often described as the weakest link, malfunctioning batteries
compromise the effectiveness of the entire UPS system and
can cost a facility thousands, if not millions, of dollars.
But in most cases, battery failures are preventable. Through
education, monitoring, and implementation of the Institute
of Electrical and Electronics Engineers, Inc. (IEEE) maintenance
recommendations, facility managers can help to ensure an
UPS system will provide emergency power at the crucial moment.
The Real Story About Batteries
There are several common misconceptions about battery life
that can compromise a facility's UPS system. However, it's
important to have an understanding of the three types of
batteries first.
There is the Vented Lead Acid (VLA) battery, also known
as lead acid flooded or wet cell. Then there's the Valve
Regulated Lead Acid (VRLA) battery. Finally, there's the
Nickel Cadmium (Ni-Cad) battery.
Both VLA and VRLA batteries are used in UPS, telecom, switch,
and control applications, while Ni-Cad batteries are found
in generator start, switch, and control applications. Ni-Cad
is also used in uncontrolled temperature applications. Now
for some clarifications.
Perception: Battery design life represents actual battery
life.
Reality: Expect to get approximately half the stated design
life with VRLA batteries.
Battery ratings are generally based on ideal conditions
rarely found in the real world. While a vented battery might
last for nearly its stated life, VRLA batteries seldom do.
This means that batteries with a 10-year design life actually
last a good four or five years.
Perception: A good voltage reading indicates a battery
contains sufficient power.
Reality: A voltage reading only shows the battery's state
of charge.
The voltage reading indicates a battery's charge as related
to its current capacity. As a battery ages, its capacity
drops, so an older battery with a 100% voltage reading may
only be at 80% of its original capacity. In other words,
a battery that passes a voltage reading may still fail in
a power emergency.
Perception: Batteries, especially VRLA batteries, are maintenance
free items.
Reality: All batteries require regular, ongoing maintenance.
The consequences of ignoring battery maintenance include
reduced battery life, compromised uptime, and jeopardized
safety.
Perception: It's okay to mix cells of different ages within
a battery.
Reality: A mix of cells with differing ages threatens the
integrity of the system and may void the battery manufacturer's
warranty.
System interdependence causes a new battery to take on
characteristics of the whole string. What seems like a savings
in the near term may actually end up costing a facility
more over time.
Perception: A battery monitor guarantees battery health
and ensures adequate UPS power.
Reality: While a battery monitor is an excellent tool, it's
just that-a tool.
Monitors are designed to measure various parameters and
store data when there's an event that's outside the normal
range. The data the monitor provides is only valuable if
someone pays attention to it and trends it to predict future
problems in the system.
Says Glenn Albér, president of Albércorp,
a Boca Raton, FL-based manufacturer of battery testing equipment
and founder of the BattCon industry symposium, "We
had a customer who installed a monitor but didn't check
the data. I went in to inspect it, and the data showed that
a power outage six months earlier had drained the UPS batteries.
If there had been another outage before the inspection,
the facility wouldn't have had the backup it was counting
on."
Knowledge Is Power
Facility managers can ensure battery health and UPS system
effectiveness by educating themselves about battery performance
and maintenance and monitoring.
1. Get educated. Facility professionals should have at
least a basic understanding of how UPS batteries work. Jim
McDowall, business development manager for North America
with Cockeysville, MD-based Saft America, says, "You
need to weigh what's serious and what's not. That allows
you to judge the ability of your staff or an external testing
company to guarantee the effectiveness of your battery backup
systems."
Resources for battery and equipment information include
manufacturers, testing and maintenance consultants, industry
seminars (www.battcon.com),
and IEEE (www.ieee.org).
2. Decide whether battery maintenance and monitoring will
be handled in-house or through an outside resource. This
decision depends on a variety of factors including staff
experience/availability, budget, and facility size. If a
facility plans to keep maintenance and monitoring in-house,
the facility manager can use IEEE and BattCon guidelines
to ensure policies and procedures are up to industry standards.
When hiring an outside company one should consider the
following:
Does the company also sell batteries? Although some of the
best maintenance and monitoring companies do sell batteries
and equipment, battery sales should not be their main source
of revenue.
How are their consultants/technicians trained? Many consultants/
technicians are former battery manufacturer employees. In
evaluating service providers, Albér recommends looking
for people with hands-on experience in testing, maintaining,
and troubleshooting battery systems. "They should have
a minimum of three years experience and participate in ongoing
training," he advises.
What types of batteries and monitoring equipment are consultants/technicians
familiar with? Which industries have they worked in? Look
for a company that has experience with a wide variety of
products, provides a range of services, and has worked in
the same industry.
What is the calibration schedule for equipment? Albér
recommends testing equipment be calibrated at least once
a year by an independent testing lab and that a testing
certificate be given to the facility manager.
How does the company incorporate IEEE standards into its
maintenance and monitoring programs? Request the consultant's
scope of work and ask how it compares to IEEE standards
(see sidebar).
3. Develop and implement an ongoing monitoring and maintenance
program. This practice helps prevent, or at least detect,
problems that might compromise the integrity of the entire
backup power system. Before developing such a program, it's
crucial to determine the battery's current state.
According to Tom Lynn, director of marketing for C&D
Technologies, Inc. of Blue Bell, PA, "The key to reliability
is implementing and using an ongoing maintenance program
that trends current data against baseline readings."
A capacity test measures the energy the battery is currently
able to store and provides a baseline that makes it possible
to estimate the battery's life expectancy.
On this test, Albér notes, "If your capacity
reading is at 90% or more of the manufacturer's specified
capacity, you probably have a few years left. If you're
at 80%-commonly recognized as a battery's end of life-you
need to replace your batteries."
Even a short power outage can be devastating and can cost
a facility thousands of dollars in expenses and lost revenue.
Only a well maintained UPS system with reliable battery
backup can guarantee power will be delivered when it's needed.
Donato is the battery products manager for J.T. Packard
located in Verona, WI. Donato can be reached at jdonato@jtpackard.com.
