Post on 27-Jul-2018
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Battery Monitoring Fundamentals & Experience
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BTECH’s History and Experiences
Why Battery Monitoring is Valuable
Battery Maintenance & Monitoring Standards
Examples of Battery Failures
BTECH’s S5 Battery Monitoring System
BTECH’s Patented Technology
This Presentation Covers…
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BTECH developed the first stationary battery monitor based on trend analysis in 1991, based on research begun in the 1980s Leading Indicator: Impedance Rise
Technology has proven itself in the past 15 years First challenge met: proving the method of continuous
battery monitoring Action Plan: Weak cells are identified and replaced
before battery system performance is affected
Battery Monitoring Introduction
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Customers That Embraced Battery Monitoring Have: Eliminated their battery failure risk Ensured performance of their critical power systems Reduced battery maintenance costs
Remote Monitoring Of Hundreds Of Battery Systems Has Demonstrated: Many previously undocumented battery conditions Proof that a need for change is required in the way
critical battery systems are managed Over 4,500 systems installed worldwide
Battery Monitoring Introduction
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Mission Critical Systems Require The Benefits Of On-line Battery Monitoring Systems Real time conditions can be identified and managed,
discharges/thermal runaway / environmental / system failures
Best possible reliability and practices demanded(TIA-942, tier 4)
Systems cannot always be taken of-line for maintenance Extensive annual or periodic tests are expensive and
interrupt business operations Budget constraints often limit or eliminate battery
maintenance Personnel changes
Why Critical System Batteries Should Be Monitored
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Up To 85% Of All Back Up Power System Failures Are Battery Related Monitoring systems can’t detect failures proactively Failures occur between service intervals Inconsistent and often compromised maintenance I.E.E.E recommends measuring the voltage and
impedance values of batteries Lack of customer awareness and/or expertise
Battery Failure Can Happen In 2 Weeks Failure can occur at any time in the battery life cycle Successful discharges or discharge tests can speed failure A quarterly check cannot assure the battery system will
perform
Why Critical System Batteries Should Be Monitored
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Early Detection Is The Key To Improving Reliability
Why Critical System Batteries Should Be Monitored
Theoretical vs Actual Failure Rate
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1015202530354045
1 2 3 4 5 6 7
Years
% F
ailu
res
Theoretical vs Actual Failure Rate
05
1015202530354045
1 2 3 4 5 6 7
Years
% F
ailu
res
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5+% Of New Batteries Fail Within The Warranty Period Significant impact to critical system reliability Installing new batteries does not reduce risk of failure Users need a method to find the bad ones in time
A warranty is not the same as a performance guarantee
Changes Happening In The Battery Industry China as main supplier of lead and batteries Many new battery types have entered the market
with little or no track record Manufacturers are under pressure to reduce cost The quality of batteries in the market has suffered
Why Critical System Batteries Should Be Monitored
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Battery Life Cycle Graph For VRLA Batteries
Impedance Vs. Capacity
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Improve the Way Batteries are Managed
Move From a Fixed Battery Maintenance Schedule to 24x7 Battery Management – 52 PM’s per Year
Instead of 4
Battery MaintenanceBattery checking and
assurance occurs only 4 days of the year -- as
quarterly battery service is performed
Battery ManagementBattery assurance
occurs 24 X 7
® Industry Standards
IEEE Std 450, IEEE Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-Acid Batteries for Stationary Applications
IEEE Std 1188, IEEE Recommended Practice for Maintenance, Testing, and Replacement of Valve-
IEEE Std 1491, IEEE Guide for Selection and Use of Battery Monitoring Equipment in Stationary Applications
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IEEE Std 1491 Recommendations
Voltage: Cell, groups of cells, string, and battery terminal voltages.
Current: Individual cell, string, float, charge, and discharge currents are measured and recorded.
Temperature: Cell/battery and ambient temperatures are measured and recorded.
Interconnection resistance checks: Intercell and battery connections are measured and recorded in ohms.
Internal ohmic measurement checks: Each cell/battery is measured for ohmic values.
Specific gravity: Each cell is measured for its specific gravity level.
Electrolyte levels: Each cell is measured for its electrolyte level.
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IEEE Std 1491 Recommendations
Discharge run-time analysis: Some monitors may incorporate a run-time prediction during discharge.
Data analysis and reporting : Data is analyzed for trending over time and should be compared with baseline values.. All systems should be capable of immediately reporting serious out-of-tolerance conditions.
Frequency: The measurement intervals are dependent on the individual hardware selected and may be programmable.
AC ripple current: AC components of the string current are measured and recorded. In multistring installations, each string measurement is made and recorded.
Coup de Fouet: Initial voltage drop and recovery of the battery under load.
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Communication interface - Data collected or reported by the battery monitoring device must be integrated. Communication can be as simple as a contact closure or as sophisticated as a fully networked Web-based operation.
Local communications - The monitoring system is usually equipped with a local interface. Local communications will be dependent on site requirements.
Remote communications - Remote communications generally represents communication between the monitoring system and an offsite location. Remote communications will be dependent on site requirements.
Communication protocols and hardware interfaces - Both local and remote communications must occur with a protocol standard over a hardware interface. These may be proprietary standards or a combination of commonly accepted communication standards.
IEEE Std 1491 Recommendations
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Examples Of Battery Failures
Found At
Customer Sites
Examples Of Battery Failures
Found At
Customer Sites
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Float Voltages vs. Unit Number
Example #1 - 2 Strings of 40-12V VRLAs
Float Voltages Show System Is OK
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Impedance vs. Unit Number
The Unit Impedances Show Another Story
Example #1 - 2 Strings of 40-12V VRLAs
Green: Initial Read (Baseline)
Red: Maintenance Limit (+20%)
Purple: Critical Limit (+30)
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Voltage vs. Time: Voltage Looks OK
Each Yellow Point = One Week
Example #2 – Unit #6
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Impedance vs. Time: Impedance Rises 120%
Green: Initial Read (Baseline)
Red: Maintenance Limit (+20%)
Purple: Critical Limit (+30)
Example #2 – Unit #6
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Voltage vs. Time: Voltage Drops 10%
Unit 50 Impedance: 5.06 Milli-ohms (180.07% of String Initial Measurement) [2.81 Milli-ohms]
Example #3 - Unit 13
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Impedance vs. Time: 120% in Two Weeks
Failure Within 2 Weeks
Example #3 - Unit 13
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Voltage vs. Time: 10% Voltage Drop within 2 Weeks
Example #4 – Wet Cell Unit 213
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Impedance vs. Time: No Change Recorded
Customer Replaced the Unit
Example #4 - Wet Cell Unit 213
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Impedance vs. Time: Effects of Re-Torquing
Example #5 - Unit 67
Customer Notified
Service Provider
Retorques
Battery Finally
Replaced
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Voltage vs. Time: Note That Voltages Have Barely Changed
Example #5 - Unit 67
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Voltage vs. Time: Detecting Thermal Runaway
Example #6 - Unit 42
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Temperature vs. Time: Detecting Thermal Runaway
Example #6 - Unit 42
Temperature Sensor Mounted in Cabinet
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System Voltage vs. Time: No Changes
Example #6 - Unit 42
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Impedance vs. Unit Number
Example #7 - Unit Impedances
Notice the 5 Units With High Impedance
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Voltage vs. Unit Number During Discharge
Example #7 - Unit Voltages
These 5 Units Have the Lowest Voltage After Discharge
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Battery Discharge Test Results – JP Morgan 270 Park Ave NYC
Example # 8 – Unit Failing During Discharge Test
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Battery Discharge Test Results – Unit 234 Begins to Collapse
Example # 8 – Unit Failing During Discharge Test
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Battery Discharge Test Results – 9:35 Into Test
Example # 8 – Unit Failing During Discharge Test
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Battery Discharge Test Results – End of Test
Example # 8 – Unit Failing During Discharge Test
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Battery Discharge Test Results – Unit 234 Discharge Details
Example # 8 – Unit Failing During Discharge Test
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The Product
BTECH’s Fifth Generation Battery Monitoring System
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SCM-600 Control Module
Voltage VM24i Module VM24i with CT
Real Time Monitoring• Cell Impedance • Ambient & Pilot Temperature
• String & System Current (Float/Charge/Discharge)• Cell & System Voltage (Float/Discharge)
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Modular System Components
® Integration and Communication
Impedance emperature
Delta T Current (Float/Discharge )
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S5 System Diagram
System Components SCM 600 (Controller)
1 per UPS or Inverter System
VM-24Up to 24 VSLs and 4 Ts per unit
CT – Current Transducer 1 per String
VSL – Voltage Sense Lead
LCL – Load Control Lead
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® Typical Applications
UPS Applications
Switchgear
Telco’s
Station Battery Systems
Emergency Lighting
Gensets
® Battery Types
2 Volt Cells
VLA, VRLAMonoblocks
4, 6, 8, 12, 16 Volts NiCad's 1.2 Volts
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Unmanned Communications: 48V VRLA Stack
S5 VRLA Stack InstallationTM
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3-Phase UPS: 40-12v (480V) VRLAs
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S5 VRLA Cabinet Installation
® S5 VRLA Station Battery System
Switchgear: 10-12 Volt VRLA’s
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125 Volt Switchgear: 93 Cell NiCad System
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S5 Switchgear
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3-Phase UPS: 480 Volt, 240 Cell System
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S5 UPS 2 Volt Wet Cells
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3-Phase UPS: 480 Volt, 240 Cell System
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S5 UPS 2 Volt VRLA Stack
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3-Phase UPS: 480 Volt, 240 Cell System
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S5 UPS VRLA
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(3) 3-Phase UPS: 480 Volt, 240 Cell Systems
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S5 UPS Wet Cell Application
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(1) 125 Volt, 60 Cell Systems
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S5 Switchgear Application
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Measurement of key battery performance parametersfor trend analysis (failure prediction & prevention)
Unit Impedance - Impedance is the leading indicator of battery failure and finds bad batteries Plate cracking, warping, corrosion, post & strap
corrosion and cell dry-out are easily detectible Interconnect problems Initial measurements for each unit used for baselines
Unit Voltage – Can also be a leading indicator of failure Dendritic shorts Thermal runaway
Ambient & Pilot Cell Temperatures – Problem prevention Environmental conditions
S5 Standard Features and Functions
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Interactive Battery Map
BTECH BVM Software
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Unit Anomalies
BTECH BVM Software
Low Unit Voltage
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Unit Anomalies
BTECH BVM Software
Differential Impedances
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S5 Real Time Functionality
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BTECH Software
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BTECH Software
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BMS
Integration and Communication
® Integration and Communication
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Additional S5 System Features
Complete Isolation from the Battery String System is not powered by your batteries Completely invisible and passive to the battery system,
UPS/rectifier and load Factory Designed and Built Wiring Harnesses
Ensure system reliability Simple installation in 50% less time Designed to meet site requirements
BTECH’s Unique Safety Fuse System Allows easy battery replacement Reduces battery replacement costs by up to 50%
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Ohmic Measurement Is the terminology used by the IEEE to
describe the measurement of a battery
cell’s Internal Resistance.
Resistance Conductance Impedance
What is an Ohmic Measurement
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BTECH utilizes an impedance measurement method to determine the ohmic value.
Why? Impedance is the only methodology that
captures all modes of cell failure Corrosion Dry out Sulfation Optimized impedance test signal Scaled to the battery type
Why Use Impedance?
® How to Measure Internal Resistance
Typical Lead Acid Model
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® How to Measure Internal Resistance
Rs Series resistance (metallic), posts, straps, plate to strap, and intercell welds. Acts as a simple resistor so does not change with frequency.
Rct - Charge transfer resistance (electrochemical) Cdl - Double layer capacitance (electrochemical),
charge separation near the surface of the electrodes from ions close to the plate surface.
Zw - Warburg (Diffusional) impedance (electrochemical), non linear diffusion of ions in the electrolyte.
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® How to Measure Internal Resistance
Internal ohmic testing is based on measuring the response of the cell to a voltage or current stimulus, and relating the response to an ohmic value. The values of the components of the model (Rs, Cdl,
and Rct) correlate to the ohmic value calculated by the instrument.
A high frequency test signal will tend toward Rs The Metallic Resistor
A low frequency test signal will tend towards Rs + Rct + Zw The entire battery
At high frequency Z ≈ Rs At low frequency Z ≈ Rs + Rct + Zw Tests at no frequency tend toward RS
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A DC resistance test only measures Rs and
Rct and ignores Zw and Cdl
Impedance testing uses an AC signal to
include the capacitor in the measurement
BTECH 215 Ω, Voltage, Current
Simple Battery Model
® BTECH’s Impedance Method
BTECH Impedance Does Not Discharge Your Batteries
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S5 System Diagram
System Components SCM 600 (Controller)
1 per UPS or Inverter System
VM-24Up to 24 VSLs and 4 Ts per unit
CT – Current Transducer 1 per String
VSL – Voltage Sense Lead
LCL – Load Control Lead
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Impedance vs. Resistance (i.e. “Voltage Response”) Voltage response results on battery systems on-line are
affected by the charger, line noise and battery type 1 cycle measurement window Requires repeated deep DC discharges to get results Measurements are not repeatable
Modular Monitoring Systems Small modules located on and powered by the batteries at all
times Wireless or fiber optic communications buss Measurements remain dormant until called upon by PC based
master Weak load signal (1A) provides poor signal to noise ratio Technology is limited to a few battery types
Comparison With Other Methods
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Impedance vs. Voltage Response
Effect of Testing on Batteries
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Systems Using AC Ripple Or Line Voltage Measurement signal is always changing due to ripple,
noise and load, leading to inconsistent results Impossible to separate ripple effects from data Cannot establish baselines for trending
Additional Comparisons BTECH Systems install in half the time with less wiring BTECH integrates with any battery type Integrates with any building management system Easily integrates with network operations Easy to operate point and click software Does not require a computer in the UPS room, each
BTECH unit functions as it own master
Comparison With Other Methods
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2.39
2.10
2.27 2.305
2.34
VoltsPerCell
Advanced Battery Management Integration
BTECH Impedance Measurement Window
® Optimized Impedance Test Cycle
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Critical system battery performance is assured Detection of major battery problems with enough time
to respond Reliability of backup power is increased Risk and revenue lost due to downtime are virtually
eliminated
Battery management and maintenance costs can be reduced significantly Customer experience: Battery service life can be
increased up to 100% when weak cells are replaced in time
Reduction of manual maintenance
Benefits of Battery Monitoring
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System up time is increased Maintenance windows are shortened Batteries can be replaced proactively
Site acceptance testing is improved Battery data is captured with the BTECH System Additional equipment does not have to be rented Defective cells can be replaced before the
UPS/Battery system is put on line Overall Battery management is improved
Better overall evaluation and management of the total Battery Asset with Real time and Trended data
Improve continuity of service and system performance Better compliance with Industry and Local standards
Benefits of Battery Monitoring
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BTECH World Headquarters – Rockaway New Jersey USA
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Wosub, HUB Zone Certification Complete Services:
Complete Documentation and Submittals Turn key project Management Engineering and Design Installation Services Commissioning, Start-up and Training
Remote Monitoring and Maintenance Contracts Technical Help Desk Support World Wide Service Network
BTECH Corporate Capabilities
® Field Service and Support
BTECH Direct Service
Factory Authorized Partners
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Projects and Customers
Scope: Provide all monitoring hardware for
ongoing system expansion and
developments
Maintenance and Monitoring service
provided for 19 centers, 228 systems
Status –On-line/ in process
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Project Dolphin (Apple Data Center) Scope: provide Battery monitoring systems
and technical support (48) 240 Cell systems Largest Commercial Data Center in North
America
Status - in process
Projects and Customers
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Project Spirit (Blackberry Data Center)
Scope: provide battery monitoring systems and technical support (14) Systems deployed Status – Project complete, on-line
Projects and Customers
® BTECH – Strategic Customers