what can go wrong with a capacity test
TRANSCRIPT
WHAT CAN GO WRONG WITH A
UPS CAPACITY TESTJohn Polenz
Emerson Network Power Liebert Services
WHAT CAN GO WRONG WITH A UPS CAPACITY TEST?
Prior to the test During the test After the test
WHAT CAN GO WRONG PRIOR TO THE TEST?
WHAT AND HOW WILL THE TEST BE CONDUCTED?
Just kill the input and let’er run till she drops and see how long it runs!
HOW WILL THE TEST BE PERFORMED?
Do you use IEEE 1188, 450, &1106 as a reference and guide?
Do you know what the Battery Manufacturer requirements are?
BATTERY PRE-TEST REQUIREMENTS UNKNOWN! Most require initial/equalize charge –
Really? 72 hour float after equalize and prior to
testingCool down?Dissipation of Gas build up on plates
Initial/equalize Timelines for VLA can be extensive150 hrs vs 24 hrs
Ensuring Full state of ChargeConstruction events
Constant current testing vs constant power
WHAT TYPE OF TEST ARE YOU CONDUCTING System functionality vs Battery capacity More than not with UPS applications
Primarily acceptance testing No planning or knowledge of battery
manufacturers requirements for capacity testing IOM not reviewedTimeline issues
DO YOU KNOW WHAT TO TEST TO? Test requirements
What is the actual sizing of the battery?
You mean I have to know the sizing for the battery?
WHAT IS TAKEN INTO ACCOUNT FOR UPS BATTERY SIZING KVA/KW load Inverter efficiencies Power factor Aging factor Temperature Number of cells/string Put the info into the formulas-KVA Rating X Power Factor = KW Load KW Load ÷ Inverter Efficiency = KW Battery LoadKW Battery Load ÷ # of Cells = W/Cell requirement
This is the “WHY” you want to test as a system!
LACK OF BATTERY PREP FOR THE TEST What prepping?
The battery has been on float for a couple of days
You discover that the battery has been discharged multiple times due to SAT requirements
UPS voltage setting not verified prior to the test
UPS End Cell Voltage not verified or known Voltage drop in system
Battery and UPS to battery connections
LACK OF BATTERY PREP PRIOR TO THE TEST Temperature is not considered as an
issue Not prepped as required by the
manufacturer Not enough time in schedule Didn’t have the information Didn’t realize the requirements existed Assumed just a 15 minute battery
WHAT CAN GO WRONG DURING THE TEST? No data recording
Data logging equipment issues Inadequate data collected
System data only at the UPS At the beginning and at the end of the test
IR testing -Thermal concerns –when do we stop the test? Connection concerns
High resistance –high temperatures Battery temperature
No parameters established Cell reversal Equipment malfunctions
WHAT CAN GO WRONG AFTER THE TEST?
FAILED TESTS – ARE THEY REALLY? It didn’t make the time!
The system only ran for 6.5 minutes instead of 8 minutes
Battery temperature was found to be 62F Not all the units met the ECV requirement!
System vs. individual cell/unit ECV Some units fell below specified ECV Test ran for 15 minutes, but battery was sized
for 10 minutes? Not tested at 77F(25C)
Temperature was at 62F Didn’t ensure battery was at FSOC
FAILED TESTS – ARE THEY REALLY? Didn’t perform initial charge Didn’t perform initial charge properly Didn’t provide 72hr float prior to testing No monitoring for the test – only system
level monitoringNo data to prove or disprove
FAILED TESTS – ARE THEY REALLY? Metering not calibrated Only using UPS meters to collect system
data
Time not monitored during the test Not every cell/unit met the ECV cutoff –
1.60-1.67 v/c
PERCEIVED FAILED TESTS Didn’t make time! No final data review No calculations to verify test results
Are not familiar with IEEE rate adjusted or time adjusted calculations
No one knows actual sizing of the battery
Test stopped before it should beWrong ECVWrong time
No agreement on “stop test” criteria
WHAT CAN GO WRONG Lack of prior planning
When to stop the test is not known Improper equipment used
Wrong size (voltage)load bankCan cause a fire
Issues with equipmentOut of calibrationDoesn't measure properlyDoesn’t record good data to be reviewedDoesn’t record the data at all
WHAT CAN GO WRONG Test Equipment failures Facility damage Misinterpretation of battery capacity Delays in commissioning Additional costs incurred
Expect tests to be run until the battery makes the numbers!
Customer dissatisfaction Battery failed
MORAL TO THE STORY Make no Judgment calls prior to data analysis
Alarms customer! Plan the testing
Agreement on: Testing parameters Testing procedures Capacity calculations/analysis process Timelines
Know the battery parametersSizingTemperature impactECV
MORAL TO THE STORY Collect proper data
System levelCell/unit levelThe more the better!
Analyze the data collected IEEE 1188, 450, 1106Rate adjusted method
Consult the battery manufacturer’s if there are questions/concerns
THANK YOU FOR YOUR ATTENTION!