Conductance Measurement as an Aid to Determining Replacement

Conductance Measurement as an Aid to Determining Replacement Strategy - Its application worldwide - Youngdae Jun Korea Thermo-Tech Co. , Ltd. Korea March 30, 2004

Lead-Acid Battery Reaction + Chemical - + CATHODE ANODE H 2 SO 4 CATHODE ANODE Pb. O 2 H 2 O Pb Pb. SO 4 LEAD DIOXIDE Sulfuric Acid & Water Electrolyte LEAD SULPHATE Pb. O 2 + Pb + 2 H 2 SO 4 CHARGE DISCHARGE H 2 O Pb. SO 4 LEAD SULPHATE 2 Pb. SO 4 + 2 H 2 O

Battery Routine Inspection • 1. Visual Inspection • 2. State of Charge (SOC) – Open Circuit Voltage (OCV) – Specific Gravity (S. G. ) • 3. State of Health (SOH) Percentage of Capacity Over 90% - Excellent Over 80% - Good Below 80% - No Good

IEEE Standard 1188 -1996 Degradation is indicated when the battery capacity drops more than 10% from its capacity on the previous performance tests, or is below 90% of the manufacturers published ratings. (p. 6) A capacity below 80% shows that the battery rate of deterioration is increasing even if there is ample capacity to meet the load requirements. (p. 9)

Battery Capacity Testing Automotive Standby Motive Power Testing Decision Long period of time, stable current when power is out Long period of time, stable current for driving forklift, etc. -18℃ Cold Cranking Ampere-Hours (Ah) Ampere-hours (Ah) e. g. ： 500 CCA e. g. : 200 Ah, 10 h rate e. g. : 100 Ah, 10 h rate Time Discharge Test： Time Discharge Test: Room temp. 250 A load、 Room temp. 20 A load、 Room temp. 10 A load Discharge 15 s、see V drop Rating Short period of time, big current to start engine ½ CCA Discharge Test: Function Discharge 10 h、see V drop 12 V Battery ＜ 9. 6 V No Good 2 V Cell ＜ 1. 75 V No Good Capacity ＜ 80% N. G.

Conductance Measurements • It is a measure of the plate surface which determines how much chemical reaction or power the battery can generate. • The battery state of health can be diagnosed by the change of the plate surface.

Conductance and Discharge Test e. g. A bottle has 500 ml of water，how do you know if the bottle has less than 400 ml of water（80%）？ a) by cup measure b) c) by weight By water level Conductance measurement is like weight or water level measurement to monitor the loss of water and calculate the remaining volume of water (capacity).

How Conductance Test Is Performed (IEEE Standard 1188 -1996) Conductance measurements can be performed by applying a voltage of known frequency and amplitude across a cell / unit and observing the AC current that flows in response to it. The conductance is the ratio of the AC current component that is in-phase with the AC voltage, to the amplitude of the ac voltage producing it. (p. 15) Significant changes in the value typically indicate a significant change in the cell, which may be reflected in its performance. (p. 15). Changes in ohmic values in excess of 20% should be considered significant. (p. 15)

Conductance Test 1. A low voltage A/C Signal is Impressed across the battery terminals (VAC) 2. 3. The A/C Current (IAC) Response is measured Conductance (G) is calculated using Ohm’s Law: G = IAC/VAC Plate Surface Area

% Original Value % Rated Capacity Linear Relationship 100 95 % Rated Capacity 90 85 80 130 120 110 100 Conductance 90 80 10 20 Source: Johnson Controls Form 41 -7271 Rev. 8/94 30 40 50 % Life 60 70 80 90 100

Conductance Correlation with Battery Capacity

Application in Auto Industry N. America Europe Japan Others GM Opel Fiat Toyota SGM MCR-410 MCR-411 MCR-360 MCR-440 MCR-430 AP FORD BMW Renault Nissan Hyundai MCR-490/390 MCR-560 MCR-330 MCR-620 MCR-570 Chrysler Mercedes Audi/VW Mitsubishi Proton MCR-420 MCR-717 MCR-340 MCR-530 MCR-500 AP Volvo Land Rover Mazda MCR-320 MCR-393 MCR-491 Saab Jaguar Honda MCR-311 MCR-394 MCR-540

Application in Battery Industry Exide Yuasa MCR-350 MCR-417 GNB Furukawa Napa PSM-2 Interstate CPS-3000 MCR-430 AP ACDelco Varta Shanghai MCR-400 Delphi MCR-450 Wal-Mart MCR-500 LBSA MCR-460 AP Century Yuasa MCR-400

Application in Standby Industry

Internal Ohmic Measurements Impedance measurements can be performed by passing a current of known frequency and amplitude through the battery and measuring the resultant ac voltage drop across each cell/unit. Conductance measurement can be performed by applying a voltage of known frequency and amplitude across a cell/unit and observing the ac current that flows in response to it. Resistance measurements can be performed by applying a load across the cell/unit and measuring the step change in voltage and current. Impedance and resistance are inversely related to conductance.

Among the three ohmic testing methods, why customers choose Midtronics conductance tester not impedance or resistance On-line Test Data: Reliable and Repeatable Easy of Use and Reasonable Price Company Reputation and After-sales Service New Technology & Product Research & Development

Electric Power Research Institute (USA) “Battery Performance Monitoring by Internal Ohmic Measurement” Testing performed as part of this project indicates that a linear relationship appears to exist most often between conductance and capacity. The practical implication of this observation is that an inverse relationship should exist between impedance or resistance and capacity. (2 -19) EPRI TR-108826, December 1997

British Telecom Paper at Intelec 1998 “Impedance/Conductance Measurements as an Aid to Determining Replacement Strategy” Conclusions: This paper has shown that two particular parameters, namely conductance/impedance monitoring and temperature/time/life factors can be effective in forecasting battery replacement timescales. (In 1999 British Telecom (BT) purchased 500 units of Midtronics Micro Celltron tester to equip its technicians. By the end of 2001, BT had purchased 700 units of Midtronics Micro Celltron tester. )

France Telecom Paper at Intelec 2001 “Measurement of Impedance and Conductance: Myth and Reality Tested in the Field” Analysis and Conclusion In a power system architecture serving telecommunications equipment, batteries are used in an emergency through lack of normal electrical supply, generally the mains. It is therefore absolutely impossible to disconnect them to test their residual capacity by measurement of conductance or impedance. These must be carried out online. Consequently, as soon as a battery is made up of more than one string, it is necessary to take into account the correction factor. (p. 419, Analysis and Conclusion)

France Telecom Paper at Intelec 2001 “Measurement of Impedance and Conductance: Myth and Reality Tested in the Field” (continue from previous page) For test apparatus A, measuring conductance, measurement and the correction factor are reliable. It applies power to the terminals of the tested monobloc and measures the current. These two parameters are therefore mastered. For test apparatus B, measuring impedance, it is not adapted to multistring batteries in a traditional telecom context. It applies a current that is divided into all the strings of the battery. The current then developed at the terminals of the tested monobloc is usually too weak to be correctly measured by the tester (Table 6). (p. 419, Analysis and Conclusion)

France Telecom Paper at Intelec 2001 “Measurement of Impedance and Conductance: Myth and Reality Tested in the Field” (continue from previous page) Regarding the conductance measured with apparatus A, the fault thresholds determined from measurements on more than 1200 monoblocs (AGM 12 V 75 Ah) are as follows: Loss of conductance less than 30% = loss of capacity less than 20% Loss of conductance more than 40% = loss of capacity more than 20% (p. 420, Measurement Results)

Time Warner Telecom (USA) “Letter of Product Recommendation” Feb. 29, 2000 A simple, fast, economical, and relatively accurate tool is required as a result of the increasing need for the testing and maintenance of the batteries being utilized in our network. Several battery testers have been tested in our lab and in the field. In terms of accuracy, cost, ease of operation, safety and reputation for good product support, we have determined that Midtronics Micro Celltron Conductance Tester is the recommended battery tester for TWTC.

NEXTELL (USA) “DC Power and Battery Plant Optimization and Periodic Battery Plant Preventive Maintenance Procedure” Rev. 1. 1 April 10, 2001 8. 0 Estimating Battery Runtime – Load/Conductance Testing The ability of the battery plant to support the load should be performed annually after all other maintenance procedures have been completed. The runtime available from a battery plant can be determined in two ways. One method is to simply shut down the rectifier and let the site run on battery power. While this is easy, it runs the risk of dropping the site if the batteries are defective. Conductance testing produces more accurate results, and has no risk of dropping the load from the plant.

Bell Atlantic (USA) “Product Selection Notice – Midtronics Micro Celltron Battery Conductance Tester” Transport Technology Planning Group Document Number 1999 -00204 -OSP, April 15, 1999 The purpose of this Product Selection Notice is to inform the field of the selection of the Midtronics Micro Celltron Conductance Battery Tester for use in Bell Atlantic. The Micro Celltron is used for maintenance testing of valve regulated batteries in the outside plant, at customer locations or in other applications where valve regulated batteries are used. The Micro Celltron Tester provides a quick and accurate way to identify battery deficiencies by imposing a small signal during test and measuring the resulting AC current against a reference value. The test causes little change o the dynamics of the battery and can therefore be repeated as desired. The Micro Celltron Tester replaces the Midtronics Celltron Plus Tester for new purchases for in-service measurements of the condition of valve regulated batteries.

Verizon (USA) “Battery Conductance Testing M&P” (method and procedure release) April 23, 2002 This M&P is emphasizing the importance of battery conductance testing at remote terminal sites and customer premise locations equipped with battery backup. The Midtronics’ Micro Celltron conductance Meter is the test set of choice for battery testing because it is non-intrusive, intuitive, accurate, and quick compared to other forms of battery testing. Consequently, these test results will provide reliable battery health data, which will enable Verizon to manage its annual budget forecast more efficiently. “Battery Vendor will charge the battery for a period of 72 hours before shipping to site, and prior to shipment, will test each battery with a Micro Celltron Conductance test set. Additionally, the vendor will place a label on the battery with the following information: conductance reading, PO#, battery type, related volt reading and amp hour capacity. ”

Micro Celltron CTM-300 Kit • CTM-300 Complete Kit includes: • CTM-100 Micro Celltron • Protective Carry Case • IR Printer • Two Test Cables • Spare Batteries • Spare Fuses

Celltron Ultra BSU-6000 Kit • BSU-6000 Complete Kit includes: • BSU-600 Celltron Ultra • Protective Carry Case • Two Test Cables (Clamp & Probe) • Spare Batteries & Spare Fuses • IR Printer • Temp Sensor

80% Capacity versus % Conductance Battery Industry： Capacity ＜ 80% Replace Midtronics： Warning Conductance ＜ 70% ＜ 60% B. T. ： Conductance ＜ 65% ＜ 55% Replace Warning Replace France Telecom：Conductance ＞ 70% = Capacity ＞ 80% Conductance＜ 60% = Capacity＜ 80%

Guidelines on Measurement a) - The battery tested should be under stable conditions (Not in the process of charging and discharging)； b) - The battery should be tested under the same condition. (We compare apple with apple, not apple with orange); c) - The test probes should be placed as close as possible to the battery posters (to avoid the impact from other metal accessories) d) - The test can identify good or bad cells

What is New? • New Technology: DFIS (Discrete-Frequency Immittance Spectroscopy) • New Products: on. GUARD & in. GEN

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