Stationary Batteries Dispelling Popular (and not so Popular) Beliefs

IEEE Continuing Education On Demand

June 10, 2009, Sheraton Sand Ket

Stationary BatteriesDispelling Popular (and not so Popular)

Beliefs

Roy Gates - Alcad Standby Batteries

John Healy - Engineered Power Product

Houston ChapterContinuing

Education on Demand 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!)


Education on Demand

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

Battery Basics – Chemistries - Evolution


Education on Demand 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



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



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


Education on Demand

Battery Basics - Cost & Confusion

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


Education on Demand

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


Education on Demand

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


Education on Demand

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


Education on Demand Battery Maintenance

Primary function of maintenance

is not to find out why it went wrong

but,

Prevent it from going wrong


Education on DemandBattery Maintenance??

3 months on Equalize Voltage


Education on DemandBattery Maintenance ?


Education on Demand Maintenance - Safety

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)

Protective Equipment:



Use insulated tools

No smoking or open flames

Avoid arcing in the immediate vicinity of battery

Wear protective equipment

Avoid wearing metal objects

Safety Precautions:



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

Safety Precautions (cont’d):


Education on DemandName Five Things You Should

Check When Inspecting the Battery

Charge Voltage

Electrolyte Levels

Cleanliness

Corrosion

Specific Gravity


Education on Demand 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



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



1 2.23 16 2.23 31 2.23 46 2.23 60 cell, flooded lead acid

2 2.21 17 2.23 32 2.18 47 2.21 Flt V 2.23 - Eqlz 2.33at 77oF

3 2.23 18 2.22 33 2.23 48 2.23 Electrolyte Sp. Gr. 1.210

4 2.22 19 2.23 34 2.24 49 2.22

5 2.23 20 2.21 35 2.23 58 2.22

6 2.23 21 2.03 36 2.23 51 2.24

7 2.23 22 2.23 37 2.23 52 2.23

8 2.17 23 2.22 38 2.21 53 2.25

9 2.22 24 2.23 39 2.23 54 2.22

10 2.23 25 2.21 40 2.23 55 2.23

11 2.24 26 2.24 41 2.26 56 2.23

12 2.24 27 2.21 42 2.23 57 2.21

13 2.22 28 2.23 43 2.27 58 2.23

14 2.23 29 2.23 44 2.30 59 2.28

15 2.23 30 2.23 45 2.23 60 2.23

Cell 21 is below O.C.V

Cell 8 & 32 > 40mV from spec

Cells 44 & 59 are > 40mV high



1 2.18 16 2.19 31 2.18 46 2.18 60 cell, flooded lead acid

2 2.17 17 2.18 32 2.18 47 2.18 Flt V 2.23 - Eqlz 2.33at 77oF

3 2.18 18 2.18 33 2.16 48 2.15 Electrolyte Sp. Gr. 1.210

4 2.18 19 2.17 34 2.18 49 2.18

5 2.18 20 2.18 35 2.18 58 2.18

6 2.18 21 2.18 36 2.18 51 2.18

7 2.18 22 2.18 37 2.17 52 2.18

8 2.18 23 2.18 38 2.18 53 2.18

9 2.18 24 2.17 39 2.18 54 2.19

10 2.19 25 2.18 40 2.18 55 2.18

11 2.18 26 2.18 41 2.18 56 2.18

12 2.16 27 2.18 42 2.18 57 2.18

13 2.18 28 2.18 43 2.18 58 2.18

14 2.18 29 2.18 44 2.18 59 2.18

15 2.17 30 2.18 45 2.18 60 2.18

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



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



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


Education on DemandCharge Voltage

Summary - 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


Education on Demand

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


Education on Demand Visual Inspection

Very important, cost effective maintenance practice

Thorough inspection might take 15 minutes

Tools include Flashlight Clipboard Training / Experience


Education on Demand Note Anomalies


Education on Demand

Visual Inspections Include

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


Education on Demand

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


Education on Demand

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


Education on Demand

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


Education on Demand

Visual InspectionSummary - TIPSE

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


Education on Demand

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)


Education on Demand


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


Education on Demand


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


Education on Demand

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


Education on Demand

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


Education on Demand

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


Education on Demand

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


Education on Demand

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?


Education on Demand 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)

IEEE Continuing Education On Demand

June 10, 2009, Sheraton Sand Ket

On Behalf of John Healy of Engineered Power Products

Thank You Very Much!

Documents

Stationary Batteries Dispelling Popular (and not so Popular) Beliefs