Frequently Asked Questions


What is the difference between single phase and three phase AC systems?

A three phase system has a minimum of three separate voltages spaced 120o apart.  A single phase system has a minimum of one voltage.  Three phase systems provide higher efficiency and greater torque for starting motors, but are more expensive to distribute and control than single phase systems.  Single phase systems are simpler and less costly than three phase systems.

What is included in UPS, Battery and Charger PMs?

That depends on the specific system.   Stationary Battery Systems and UPS systems are complex and designed to work when no other power source is working.  Nolan Power Group uses industry standards, manufacturer’s recommendations and our extensive experience to develop maintenance practices that meet the specific needs of our customers’ complex systems.

How often should I have preventative maintenance performed on my equipment?

That depends on the specific system, where it’s installed, and how it’s used.  For instance, equipment installed in hot or dirty areas will require more frequent maintenance than the same equipment installed in a clean temperature-controlled environment.   Stationary Battery Systems and UPS systems are complex and designed to work when no other power source works.  Nolan Power Group uses industry standards, manufacturer’s recommendations and our extensive experience to develop maintenance practices and schedules that meet the specific needs of our customers’ complex systems.

Why should batteries receive a Capacity Test?

Capacity testing is an integral part of a comprehensive battery maintenance program.  Regularly scheduled capacity testing is a key part of IEEE/ANSI Standard 450-2010, which specifies minimum acceptable standards for maintenance of large lead-acid storage batteries, (IEEE/ANSI Std. 1188-2005 addresses Valve-Regulated Lead-Acid (VRLA) Batteries and IEEE/ANSI Std. 1106-2005 addresses Nickel Cadmium (NiCad) batteries).

Capacity testing serves the following purposes:

  • A properly conducted capacity test is the only scientifically proven and accepted method of determining the actual capacity of stationary lead-acid and nickel cadmium batteries.
  • A properly conducted capacity test can determine if a battery can satisfactorily support the connected load for the specified time.
  • A program of regularly-scheduled capacity tests will allow forecasting of battery replacement needs while obtaining the maximum battery service life without jeopardizing the connected load.

Additional Discussion:

  • A battery maintenance program that does not include regularly-scheduled capacity tests is essentially only ensuring that the battery has the proper electrolyte level (in vented batteries), is fully charged, and that the intercell connections are low resistance and free of corrosion.  While all these items are important to the successful operation of the battery, they do not prove or even suggest that the battery will support the connected load.
  • Numerous papers have been published postulating that internal impedance measurements can be used as a replacement for capacity testing.  This notion is false.  Internal impedance measurements can provide additional information concerning the condition of a battery, but this information is simply an inference that battery capacity might be affected.  Internal impedance measurements cannot be correlated to battery capacity except in the grossest of terms, especially in a field environment with many uncontrollable variables.  Simply stated, a properly conducted capacity test is the only method of determining battery capacity.

How often should I have my batteries capacity tested?

Testing Flooded Cells – Reference IEEE 450 (2010)

  • Acceptance Testing – confirms if battery meets manufacturer’s specifications
    • Can be performed at the factory.
    • Test performed on installation.  This is the only method that proves the battery as manufactured and installed will support the connected load.
    • Does not replace the initial performance test (see “Initial Performance Test” below)
  • Initial Performance Test – establishes a baseline for future testing
    • Within first 2 years of battery being placed in service
    • Within 2 years of Acceptance test, if performed
  • Interval Testing Recommendation  – Testing after initial baseline test
    • IEEE/ANSI Std. 450-2010 specifically states that the interval between tests should be no more than 25% of the expected service life of the battery and that the battery user needs to calculate the expected service life based upon the battery operating temperature.
    • Annual Tests are required when:
      • Battery reaches 85% of service life (e.g. 17 years of service in a 20-year design life).
      • Measured capacity loss is 10% or greater from previous test.
      • When capacity is at or below 90% of manufacturer’s published rating.
    • Nolan Power Group recommends annual testing when any of the following conditions are found
      • Battery is not installed in temperature controlled environment.
      • Battery reaches 85% of service life (e.g.  17 years of service in a 20-year design life).
      • Measured capacity change is greater than 10% from previous test.
      • When capacity is at or below 90% of manufacturer’s published rating.
      • When the battery duty cycle is one hour or less in duration.

VRLA Cells – Reference IEEE 1185 (2005)

  • Acceptance Testing – confirms if battery meets specifications
    • Test performed on installation
    • Sets baseline for future tests
  • Initial Performance Test – establishes a baseline for future testing
    • Within first year of battery being placed in service
    • Acceptance test, if performed on installation, can be considered as “initial performance test”
  • 2-Year Interval Testing Recommendation  – Testing after initial Performance Test
    • IEEE/ANSI Std. 1188-2005 states that the interval between tests should be no more than 25% of the expected service life of the battery or two years whichever is less.
    • Recommendation applies only when battery is installed in a temperature controlled environment
  • 1-Year Interval Testing Recommendation – When any of the following conditions apply
    • Internal ohmic values have changed significantly between readings
    • Significant physical changes have occurred to the cells (e.g., leakage, bulging, etc.)
    • Battery capacity drops 10% or more from its capacity on the previous performance test
    • Capacity is at or below 90% of manufacturer’s published rating.
    • Battery has reached 85% of the service life expected for the application.
    • UPS batteries where the customer specified runtime is 1 hour or less

Additional Considerations –Nolan Power Group Testing Department

The following criteria have been established by the Nolan Power Group Testing Department and are used in addition to those of the IEEE recommendations referenced above:

  • Switchgear and Turbine Batteries – Maximum 3-year interval between testing
  • Example of calculating testing frequency in a non-temperature controlled environment:  IEEE 450-2010 standard explains that the user needs to calculate the expected service of their battery depending upon the operating temperature.   A 20-year design life flooded lead-calcium battery in a non-temperature controlled environment located in the southeastern US will have an expected service life of 8-12 years.  Let’s use 10 years as the expected service life.  A flooded battery with a 10-year expected service life would require an acceptance test upon installation and performance tests at 2.5 years, 5 years, 7.5 years, and annually thereafter because the battery has reached 85% of expected service life.
    We still recommend annual capacity tests for batteries in non-temperature controlled environments as this is the only safe way to ensure maximum battery life and minimum risk to the connected load.  An “expected service life” is just that, an expectation, and we all know that expectations are not always met.
  • Batteries installed in the “cabs” of gas turbines are not typically in temperature controlled environments.  The “cool” air blown into the battery “cab” will usually limit the maximum battery temperature to 90o-95oF which hardly qualifies as a temperature controlled environment.
  • We recommend annual tests for VRLA batteries because they are inherently unreliable.  Most VRLA batteries do not meet the IEEE criteria for biannual testing.
  • We also recommend out-of-cycle capacity tests whenever the internal resistance of any cell exceeds the median resistance by 15% or more.

When should I replace my batteries?

Stationary batteries are replaced for two primary reasons: lack of capacity or an obvious physical defect.

  • Lead-Acid batteries require replacement when their capacity drops to 80% of the manufacturer’s rated capacity.
  • Some examples of physical defects requiring replacement are:
    • Cracked jar
    • Cracked jar cover
    • Nodular corrosion
    • Copper contamination
    • Excessive plate growth

Can I mix and match battery jars in a string?

No.  Cells in series must be identical.

What are the advantages and disadvantages of VLA vs VRLA batteries?

VLA advantages:

  • Long life:  The standard design life for VLA batteries of U.S. manufacture is 20 years.
  • Reliability:  No other stationary battery is as reliable as a U.S. manufactured flooded pasted plate lead-calcium battery.  This is the type of battery used in all class 1-E applications in nuclear power plants in the U.S.
  • Predictability:  The life span and discharge performance of properly maintained flooded stationary lead-acid batteries is very predictable.

VLA disadvantages:

  • Space:  Flooded lead-acid batteries are typically large and heavy.
  • Spillable acid:  The electrolyte in VLA batteries is liquid dilute sulfuric acid.  Proper installation design, installation, and maintenance ensures that acid spills aren’t a problem, but potential for a spill or leakage needs to be addressed.

VRLA advantages:

  • Space:  Most VRLA designs are very compact and allow the most power per cubic foot of space in stationary lead-acid or nickel cadmium chemistries.
  • Transportability:  Most VRLA designs are certified as spill proof by USDOT standards and can be shipped via aircraft or common carrier with no additional paperwork.

VRLA disadvantages:

  • Short life: The service life of most VRLA batteries rarely exceeds 50% of the warrantied life.
  • Unreliable: VRLA batteries have a host of potential failure mechanisms which combine to make these batteries far less reliable than VLA batteries.
  • Unpredictable: The maximum interval between capacity tests for VRLA batteries is two years due to their unreliable and unpredictable nature.

How do I properly size a battery for my application?

Follow IEEE Std. 485 or let the professionals at Nolan Power Group do it for you.  Call (985)801-5040 for technical questions and (985)801-5000 for sales.

What kind of warranty does a battery come with?

Depends upon the specific model cell and manufacturer.  Flooded Stationary Cells of U.S. typically have a 20-year warranty with the first year as a guarantee period and pro-rata warranty for the remaining 19 years. Warranties can be negotiable, so check with your sales person for details.

What kind of warranty does a UPS come with?

Depends upon the specific model UPS and manufacturer.  Warranties can be negotiable, so check with your sales person for details.

My UPS just crashed, who do I call or what do I do now?

Call the professionals of Nolan Power Group at (985)801-5000.

My load dropped, what do I do now?

Call the professionals of Nolan Power Group at (985)801-5000.

Will capacity testing “shorten” the life of my battery?

No. Capacity testing is not destructive testing. Battery life is expressed in time, usually years in float service, and in number of discharge cycles. The depth of discharge is assumed to be 80% unless otherwise specified. For example, the standard U.S. manufactured flooded lead-calcium battery has a twenty-year design life, in full float service, and has a discharge cycle life of approximately fifty deep discharges, 80% depth of discharge. This means that the battery, with proper care, will last for twenty years OR fifty deep discharges. A capacity test is a controlled discharge of a battery or cell to a specified end voltage. Some battery life is consumed in a capacity test, but the amount of life consumed is minimal and depends on the type of battery, depth of discharge and test frequency.

What’s the difference between KW and KVA?  How do you go from KVA to KW?

Kilowatts is a measure of true power while KVA is a measure of apparent power. True power is the power available to produce work. Apparent power is the sum of true power and wattless power. The difference between the two measurements is the relationship between the current and voltage waveforms. In an AC (alternating current) circuit, the current and voltage waveforms are rarely in phase. True power, (KW), is greatest when the current and voltage waveforms are in phase and declines as the two waveforms shift further apart. True power is at zero when the current and voltage waveforms are 90% out of phase. The relationship between the current and voltage waveforms is expressed as power factor (PF).

The formula for KW is: (Volts x Amps x Power Factor) ÷ 1000 = KW

The formula for KVA is: (Volts x Amps) ÷ 1000 = KVA

Are “maintenance free” batteries really maintenance free?

No. The proper name for “Maintenance-Free” batteries is Valve Regulated Lead Acid (VRLA) batteries. According to IEEE/ANSI Std. 1188, VLRA batteries require far more inspections and testing than traditional flooded lead-acid batteries. This is because VRLA batteries are not as reliable or as predictable as flooded lead acid batteries.

How do I calculate the amount of H2 gas my battery generates?

Significant amounts of hydrogen are evolved only as the battery approaches full charge.  The maximum hydrogen evolution rate is 0.000267 cubic feet (7.56 x 10-6 cubic meters) per minute per charging ampere per cell at 77°F (25°C), one atmosphere.

To calculate the amount of hydrogen produced, consider an antimony alloy type (flat plate, tubular, or Manchex) battery at a point where it is nearing end of life, or equalize charge at 2.33 VPC.

Float Current demand of full charged stationary lead –acid cells.

Milliamperes per 100 Ah @ 8-hr. rate

                 Charge Voltage                          Antimony                             Calcium

                       _________________________________________________________________________________________

NEW-OLD

2.15 vpc                                     15 – 60                                 ____

2.17 vpc                                     19 – 80                                     4

2.20 vpc                                     26 – 105                                  6

2.23 vpc                                     37 –150                                   8

2.25 vpc                                     45 – 185                                  11

2.27 vpc                                     60 – 230                                  12

2.33 vpc                                   120 – 450                                 24

2.37 vpc                                  195 – 700                                 38

2.41 vpc                                  300 – 1,100                              58

                         ________________________________________________________________________________________

NOTE: The above values apply when the electrolyte temperature is 77°F (25°).
The values will double for every 15°F (8°C) of temperature rise. If the temperature drops, the current value will be halved for every 15°F (8°C) decrease. Antimony ranges indicate current increases due to cell aging.

HYDROGEN FORMULA
Formula for hydrogen evolved____C= FC/1000 x AH/100 x K x N

C = Cubic feet (cubic meters) of hydrogen per minute
FC = Float current per 100 AH (temperature compensated) in milliamperes
AH = Ampere hours (nominal 8 hr.)
K = Constant___1 AH = 0.000267 cubic feet (7.56 x 10-6) cubic meters) per minute of hydrogen
N = Number of cells

EXAMPLE
60 cell GT-41 (3,730 AH) near end of life, on equalize at 2.33 VPC at 92° (33°) electrolyte temperature.
C = 450 (from table) x 2 for 92°F (33º= 900 milliamperes
C = 900/1000 x 3,730/100 x 0.000267 cu. ft. (7.56 x 10-6 cu. m.) x 60
Hydrogen = 0.538 cu. ft. (0.0152 cu. m.) per minute

Assume a room size of 16,000 cu. ft. (452.5 cu. m.) that is allowed a 2% concentration of hydrogen or 320 cu. ft. (9.06 cu. m.). At the above hydrogen evolution rate of 0.538 cu. ft. (0.0152 cu. m.) per minute, it would require 10 hours to reach 2% concentration. Thus with one air change every 10 hours, the hydrogen concentration could be maintained below 2%.

How do I calculate what size charger I need and hours to recharge?

CHARGER SIZING FORMULA
A = D.C. output rating of charger in amperes
C = Calculated number of ampere hours discharged from battery (time in hours x load).
A = 1.1 x C/H + L
H = Number of hours recharge time.
L = Load on system in amperes.

HOURS TO RECHARGE FORMULA
H = 1.1 x C/A-L

Will preventative maintenance extend the life of my batteries?  If so, how should it be done?

Yes. Battery maintenance should be accomplished in accordance with the manufacturer’s instructions and the applicable IEEE standards. Please remember that IEEE battery maintenance standards reflect the minimum recommend maintenance practices. Your battery may require shorter maintenance intervals.

The factor having the largest impact on battery life is temperature. All batteries are temperature sensitive devices. All aspects of battery performance are affected by temperature. Low ambient temperatures reduce available capacity and require increased float voltages. High ambient temperatures cause significant reductions in battery life, increase water consumption, and require decreased float voltages. Additionally, minor variations in cell temperatures can cause significant operational problems.

For optimum life and performance, batteries should be installed in a temperature-controlled environment.

How do I correctly size my battery system and determine which battery is right for my system?

Determining the size of a battery system can sometimes be very complicated.  Factors such as number of cells needed to reach the desired voltage, maximum system voltage, minimum system voltage, float voltage, charging rate, temperature, design margin, compensation for age, initial required capacity and duty cycle can affect a battery’s sizing.

Determining which battery is needed depends upon the application such as UPS backup, switchgear, telecom etc.

Please contact NOLAN POWER GROUP and we will gladly assist you in sizing and choosing the battery system that is right for your company’s needs. Contact Us Today!