Stationary Batteries Dispelling Popular (and not so Popular) Beliefs

1. Stationary BatteriesDispelling Popular (and not so Popular) Beliefs Roy Gates - Alcad Standby Batteries John Healy - Engineered Power Product June 10, 2009, Sheraton Sand Ket

2. Today’s Agenda • Comparison of various battery technologies • Design considerations for DC applications • IEEE Standards versus IOM • The one that validates warranty • Safety precautions • This should go without saying • Maintenance procedures and corrective actions • Where the rubber meets the road (So To Speak!)

3. Battery Basics – Chemistries - Evolution • Vented lead-acid - Invented in 1860 • Current designs established in 1880s and 1890s • Plante`, Pasted plate, Tubular • 20th-century work limited mainly to alloy research • Antimony, Calcium, Selenium • Nickel-cadmium - Invented in 1900-1901 • New plate types (plastic bonded, fiber) in last 15-20 years • H, M, and L rate - plus recombinant types • Valve-regulated lead-acid (VRLA) • Developed approximately 25 years ago • Incremental changes in response to field problems • Horizontal mounting, Catalysts, re-hydration

4. Battery Basics - Chemistry • Flooded Lead Acid • Plates - Lead oxide enhanced positive, sponge lead negative • Separator - Micro-porous fiber mat, sometimes pins • Electrolyte - Sulfuric acid (H2So4) 1.205 - 1.275 Sp. Gr. • Jars - Styrene Acrylonitrile, poly-carbonate, polypropylene • Connection points - usually lead plated copper, can be tin or brass • Life - from 5 - 25+ years, depending on environment, design, application • Design flexibility • Low rate, long duration autonomy - thick plates, moderate density electrolyte - Communications, PV, true energy storage • General purpose - slightly thinner plate for better high rate discharge performance - Switchgear, turbine • High performance - thin plates for greater surface area, high strength electrolyte - UPS • Tropical - Thick plate, reduced strength electrolyte

5. Battery Basics - Chemistry • Valve Regulated Lead Acid Batteries • Plates - Flat or pasted plate - normally calcium tin mixture • Separator - Absorbent fiber mat • Electrolyte - Sulfuric acid (H2So4) - 1.250 - 1.300 Sp. Gr. • Jars - ABS, Polypropylene • Connections - Lead plated copper, tin or brass • Life - 1 to 11 years • Design flexibility • Typically all high energy • Compact footprint - horizontal mounting

6. Battery Basics - Chemistry • Nickel Cadmium • Plates - • Pocket plate • Nickel plated steel strip, perforated to contain active material - Nickel hydroxide positive, cadmium negative • Sintered / PBE • Thin nickel plated steel strip with active material coated onto plate surface • Fiber plate • Nickel plated micro-fiber with active mass imbedded within • Separator - plastic pin or grid / micro-porous fiber mat • Electrolyte - Potassium hydroxide / lithium (KoH) - 1.190 - 1.250 Sp.Gr. • Jars - Polypropylene, Rilsan, Grilamid • Connections - Nickel plated copper • Life - 15 - 25+ years, depending on environment, application

7. Cost - 100Ah reference Plante` - $100 Pasted plate - $ 78 VRLA - $ 40 Nickel Cadmium - $350 Based on Switchgear Application, 40 degrees F Plante` - $100 Pasted plate - $ 85 VRLA - $ 45 Nickel Cadmium $160 Life Plante` 25 yrs Pasted plate 15 yrs VRLA 1-11 yrs Nickel Cadmium 25 yrs Gassing All types emit hydrogen, Pb batteries give off acid vapors Ventilation All types require ventilation, VRLA especially for thermal management Maintenance All types require maintenance, including: Visual inspection Voltage Temperature Water replenishment NOT ABLE VRLA Resistance measurements Negligible value w/ Ni-Cd Discharge testing Battery Basics - Cost & Confusion

8. Battery ChemistryTrue or False • Single use batteries are called primary batteries • TRUE • VRLA batteries were developed the same time as flooded lead acid cells • FALSE • You can use the same neutralizer for lead and nicad cells • FALSE • Fiber nickel cadmium cells are good for your digestive tract • FALSE • All batteries are not created equal • TRUE

9. Reference MaterialIEEE vs IOM • IEEE Standards • 450-2002, Flooded lead acid maintenance recommendations • 1188-2005, VRLA • 1106-2005, Nickel Cadmium • Installation and Operation Manuals • What’s the difference • IEEE are general “recommendations” that covers a broad spectrum of manufacturers • They’re based on chemistry • IOM’s are specific to the battery you own • They are the care and feeding of THIS battery

10. Reference MaterialIEEE vs IOM • Both have common themes • Proper operation • Education • Ensure longevity • Offer Do’s and Don’ts • Recommend keeping maintenance records • Analyze trends • Maintain reliable battery operation • Maintain overall DC system reliability • Comply with warranty requirements • Determine the need for battery replacement

11. Battery Maintenance Primary function of maintenance is not to find out why it went wrong but,Prevent it from going wrong

12. Battery Maintenance??3 months on Equalize Voltage

13. Battery Maintenance ?

14. Maintenance - Safety Protective Equipment: • Goggles and Face Shields • Electrolyte Resistant Gloves • Protective Aprons and Overshoes • Portable or Stationary Water Facilities • Bicarbonate of Soda Solution (Lead Acid) • Citric Acid Solution (Nickel Cadmium)

15. Maintenance - Safety Safety Precautions: • Use insulated tools • No smoking or open flames • Avoid arcing in the immediate vicinity of battery • Wear protective equipment • Avoid wearing metal objects

16. Maintenance - Safety Safety Precautions (cont’d): • Ensure battery area ventilation is operable • Neutralize static buildup just before working on battery • Check Equipment • Useful tools • Fluke or other multi-meter • Hydrometer – Digital is preferred • Internal – Ohmic measuring device • Scotch brite or other mild scouring pad • Log Book

17. Name Five Things You Should Check When Inspecting the Battery • Charge Voltage • Electrolyte Levels • Cleanliness • Corrosion • Specific Gravity

18. Charge Voltage • Name the two common charge voltages. • FLOAT & EQUALIZE • Which of the two charge voltages is used in normal, standby application? • FLOAT • What is the difference between Float, Equalize, andOpen Circuit voltages (OCV)? • OCV is Sp. Gr. + 0.85 • For Example – 1.210 Sp. Gr. + 0.85 = 2.06V • How often should the Float voltage be checked? • OVERALL BATTERY VOLTAGE – MONTHLY / QUARTERLY • CELL VOLTAGES – SEMI ANNUALLY / ANNUALLY Float is that charge voltage high enough over OCV to maintain a high state of charge and ensure there’s little to no self discharge, but not so high as to cause excessive gassing or corrosion Equalize is a higher charge voltage that forces more current through the cells to help recharge and overcome minor self discharge that might occur because of internal resistance differences

19. Charge Voltage • Should you check voltages with charger ON or OFF • EITHER IS OK • CHARGER ON VERIFIES SETTING – BALANCE • CHARGER OFF TRENDS DECAY • What else is noteworthy when performing this work • OUTPUT CURRENT OF THE CHARGER • When should equalize (Boost) charging be done? • AFTER A DISCHARGE FOR QUICKER RETURN TO SERVICE • AFTER ADDING LARGE AMOUNTS OF WATER • WHEN FLOAT VOLTAGES ARE MORE THAN 20-40mV APART • WHEN ONE OR MORE CELLS ARE >20-40mV FROM SPEC

20. Charge Voltage Cell 21 is below O.C.V Cell 8 & 32 > 40mV from spec Cells 44 & 59 are > 40mV high

21. Charge Voltage Cells are uniform, but below recommended float voltage Corrective actions include: Equalize charge at 2.33VPC until current and Sp. Gr.Stabilize AND / OR Adjust float voltage to be in accordance with spec Cell 48 is pilot cell candidate

22. Charge Voltage • The effect of too low a float voltage is: • A – No effect • B – Low specific gravity and state of charge, sulfation • C – Accelerated corrosion because of temperature & charge current • To charge the battery with lower than recommended float charge: • A – Institute a program of regular equalize / high rate charging • B – Add more cells to the string • C – Remove cells from the string • The effect of too high a charge voltage is: • A – No effect • B – High state of charge and availability • C – Accelerated corrosion because of temperature & charge current

23. Charge Voltage • Measure the battery voltage by: • A – Using a DVM at the open Pos. & Neg. of the battery • B – Reading the output voltmeter on the charger • C – Recording each cell voltage and adding them up • When using “pilot cells” for voltage readings, select: • A – The first cell in the string • B – The cell with the highest voltage • C – The cell with the lowest voltage • An out-of-spec reading on the “pilot cell” should: • A – Be reason to equalize the whole battery string • B – Be reason to compare to previous readings • C – Be reason to inspect the entire battery more closely

24. Charge VoltageSummary - Review • If an inspection shows readings out of spec, what do you do? • IF overall battery voltage is low, • THEN check charger output setting – adjust if necessary • THEN verify charger setting in 4-6 weeks for drift • IF overall battery voltage is too high, • THEN verify charger isn’t in EQUALIZE mode • THEN verify charger setting is correct for the battery • THEN adjust the charger to spec • THEN verify charger setting in 4-6 weeks for drift

25. Charge VoltageSummary - Review • IF individual cell voltage(s) are low, • THEN verify it’s above OCV • THEN check connections • THEN inspect for bridged plate group (shed material) • THEN equalize charge the battery and monitor this (these) cells for improvement(Note – if individual cells drift low, other cells in the string will be correspondingly higher) • IF individual cell voltage(s) are too high, • THEN check the charger setting • THEN verify there are cells that are low • THEN correcting the low cells should balance high cells • IF cell(s) are higher without cause, THEN contact manufacturer

26. Visual Inspection • Very important, cost effective maintenance practice • Thorough inspection might take 15 minutes • Tools include • Flashlight • Clipboard • Training / Experience

27. Note Anomalies

28. Electrolyte level Plate coloration Sediment Bubbling / gassing Flame arrestor condition Cleanliness Acid tracking Terminal post condition Connecting hardware Rack condition Ventilation equipment Adequate safety equipment Clean water source Clear egress out and to safety apparatus Maintenance tools are proper and in working order Visual Inspections Include

29. Visual InspectionElectrolyte Level • Electrolyte levels should be maintained: • A – At the MAX line • B – Just above the MAX line • C – Half way between MIN – MAX line • What is lost from the cell during normal operation is: • A – Water • B – Acid • C – Water & Acid • Replace lost fluid with: • Mineral water • De-ionized or distilled water • Acid

30. Visual InspectionPlate Condition • Negative plates are light gray, while Positive plates are dark, chocolate brown color • True • False • Small, shiny sparkles on the positive plates is a sign of: • A – Electrolysis from over charging • B – Sulfation from under charging • C – Plate growth • During the life of the batteries, which plate grows • Positive plate • Negative plate

31. Visual InspectionCell Jar & Hardware • It’s normal to see small particulate at the bottom of a lead acid cell jar • True • False • It’s ok if the sediment at the bottom of the cell touch’s the plates • True • False • Possible effect of small electrolyte leaks are • A – Presenting a hazard to the technician • B – Providing a path for battery voltage to ground • C – Damage to rack and floor (surrounding area) • D – All of the above

32. Terminal Post Corrosion Design flaw Over watering Under charging Normally cosmetic, until - Mechanical failure High current discharge Integrity of Jar & Cover Clean – water only Electrolyte grounds Crazing - solvents Stresses / cracking Flame arrestor vents Plate coloration Positives – dark brown Negatives – light gray Sulfate crystals Warping – under charge Sediment space Pile – up rate, particle size Color – light then black Electrolyte Maintain between MIN – MAX Replenish with water only De-ionized best, distilled OK Free of floating materials Visual InspectionSummary - TIPSE

33. Visual InspectionSummary • IF electrolyte levels are near the MIN line • THEN add de-ionized or distilled water to at least mid-way point • IF electrolyte levels are above MAX line • THEN verify the charger isn’t in EQUALIZE mode • THEN consult with manufacturer about removing electrolyte • THEN ensure the practice is correct to not overfill the cells • IF plates are anything other than light gray negative and dark brown positive • THEN check the charge voltage is adequate for the cells • THEN check that specific gravity is within spec. • THEN verify polarity is correct • THEN contact manufacturer (have photo’s if possible)

34. Visual InspectionSummary • IF plates sparkle when light shone on them • THEN verify the charger is working • THEN check the charge voltage is adequate • THEN check the specific gravity is in spec • THEN verify the battery hasn’t had a recent discharge • IF plates / sediment space show a lot of shedding • THEN verify the charge voltage isn’t too high • THEN inspect for excessive gassing • THEN check the output ripple of the charger • THEN check that the battery isn’t cycling frequently

35. Visual InspectionSummary • IF there are electrolyte tracks / leaks on the cells • THEN wipe with clean, water moistened cloth • Watch for static • THEN inspect the cell(s) for leaks (vent cap, jar / cover joint) • THEN check inspection log to see if water had been recently added (are the cells low again) • THEN check for ground detection alarms on charger or SCADA • IF cell(s) gassing aggressively • THEN verify the charger setting isn’t too high • THEN lower charger setting and contact manufacturer • IF flame arrestor vents are broken or missing • THEN order replacements immediately

36. Temperature Measurements • Known facts • High temperature improves performance, reduces life • Low temperature reduces performance, has little affect on life • All lead acid batteries are very temperature sensitive • Periodic temperature readings are valuable • How do you check the temperature of a VRLA battery? • Infrared thermal scan • Contact thermometer at the negative terminal post • Using a 3/8” drill bit …. • Acceptable temperature variances • 30-35oF • 5-10oF • 0-1oF

37. Temperature Measurements • Which item below is not a likely cause for variance • Part of the battery is in front of a window • Gas (or other) heater unit • One part of the battery is near a door • Technician with a BIC • Air conditioning duct • Internal fault of a cell • The recommendation is monitor temperature of a pilot cell, which one • The first cell in the string • The cell at the center of the top row • The one that’s gassing the most • The cell that’s gassing the least

38. Temperature MeasurementSummary • High temperatures reduce useful battery life • Do what’s practical to keep temperature moderate • Low temperature reduces available performance • Taken into consideration at battery selection / sizing stage • Take into account when performing discharge tests against manufacturers data • Eliminate artificial causes of temperature imbalance • Heaters / AC • Windows

39. Discharge Capacity Testing • The only real way to verify a battery’s capacity • Capacity needs definition • Manufacturer’s say it’s @ 8hrs, to 1.75VPC, @ 77oF, fully charged • Any variation of the above changes “capacity” definition • One hour discharge test, to mfg. data is acceptable • Ideally, it trends degradation over time • Supported by intermediate activity (e.g. voltage, resistance, etc) • Breaker off test is also valuable under same conditions each time • Trend analysis critical

40. Discharge Capacity Testing • Do you prepare the battery for a discharge test? • Equalize, repair loose connections, remedy poor cells • If YES, then the test results indicate battery health • If NO, then test results may indicate corrective action …. AND RETEST • What are your expectations from the test?

41. Conclusions • There are well established battery designs available today for a variety of applications • Choose the Right Battery For The Application • IEEE Standards and IOM’s both have common objectives • Prolong your investment & increase predictive value • Maintenance procedures cannot be overstated, or ignored and still maintain reliability (and warranty)

42. On Behalf of John Healy of Engineered Power Products Thank You Very Much! June 10, 2009, Sheraton Sand Ket