Date: Wed, 28 Jun 1995 20:23:32 -0400
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: drew@interport.net (Derek Drew)
Subject: Fwd: Car Battery FAQ
>>From ChrisRosen@aol.com Mon Jun 26 21:39:02 1995
>From: ChrisRosen@aol.com
>Date: Mon, 26 Jun 1995 21:41:24 -0400
>To: drew@interport.net
>Subject: Fwd: Car Battery FAQ
>
>
>---------------------
>Forwarded message:
>From: 0005222166@mcimail.com (William Darden)
>Sender: owner-toyota-l@bgu.edu
>Reply-to: toyota-l@bgu.edu
>To: toyota-l@bgu.edu (Toyota Mailing List)
>Date: 95-06-24 18:41:02 EDT
>
>
>
> CAR BATTERY FREQUENTLY ASKED QUESTIONS
> JUNE 24, 1995
>
>
>A word of caution. Batteries contain a sulfuric acid electrolyte which is
>a highly corrosive poison and produces gasses that will explode if
>ignited. When working with batteries, you need to remove jewelry, wear
>protective clothing and eye ware, and exercise caution. Follow the
>manufacturer's instructions for testing, jumping, installing and charging.
>
>
>1. WHAT IS THE BOTTOM LINE?
>
> A. Check specific gravity in each cell and remove surface charge
>before load testing,
>
> B. Retest after deep discharges or jump starts,
>
> C. Recharge slowly at 14.6 volts,
>
> D. Buy the freshest and largest Reserve Capacity, non-sealed (low
>maintenance) car battery that will fit with a CCA rating for your climate
>that meets or exceeds the car's OEM cranking amps requirements, and
>
> E. Perform preventative maintenance, especially during warm
>weather.
>
>
>2. WHY BOTHER?
>
>Because only the rich can afford cheap batteries.....
>
>A good quality car battery will cost between $50 and $100 and, if properly
>maintained, will give you four to eight years of service. The purpose of
>a battery is to start the car; to provide power for the ignition, lighting
>and other accessories when their combined load exceeds the capability of
>the alternator; and to filter the power. Dead batteries almost always
>occur at the most inopportune times, e.g., returning home from a long
>trip, during bad weather, late at night in a dark parking lot or when you
>are late for an appointment. You can easily spend the cost of a new
>battery or more for an emergency jump start or tow.
>
>Most store employees do not know how to correctly test a battery. The
>national average of "defective" batteries returned to the manufacturer
>that are in fact good is 50%.
>
>
>3. HOW DO I TEST A BATTERY?
>
> A. Visually inspect for obvious problems, e.g., damaged case,
>corrosion, loose hold-down clamps or cable terminals, or low electrolyte.
>
> B. If you have just recharged you battery or driven your car,
>eliminate any surface charge by one of the following methods; otherwise,
>go to the next step:
>
> 1. Allow the battery to sit for two to three hours,
>
> 2. Turn the headlights on high beam for three minutes and
> wait five minutes before further testing, or
>
> 3. With a battery load tester, apply a 150 amp load
> for 10-15 seconds.
>
> C. Using the following table, determine the battery's
>state-of-charge. The BEST way to measure the state-of-charge is to check
>the specific gravity in each cell with a hydrometer. A temperature
>compensating hydrometer can be purchased at a auto parts store for
>approximately five dollars. If the battery is sealed (maintenance free),
>the correct procedure to test it is to measure the battery's voltage
>WITHOUT the engine running with a good quality digital DC voltmeter. Some
>sealed batteries have built-in hydrometers. They are not good testing
>devices because they only measure the state-of-charge in one of the six
>cells.
>
>If the state-of-charge is BELOW 75% using either test, then the battery
>needs to be recharged BEFORE proceeding. If there is a .050 or more
>difference in the specific gravity reading between the highest and lowest
>cell or the battery will not recharge to 75% or higher, then the battery
>should be replaced.
>
> Battery Approximate Average Cell
> Voltage State-of-charge Specific Gravity
>
> 12.66 100% 1.265
>
> 12.45 75% 1.225
>
> 12.24 50% 1.190
>
> 12.06 25% 1.155
>
> 11.89 0% 1.120
>
>Note: If the temperature of the electrolyte is below 70 degrees F, then
>add .012 volts (12 millivolts) per degree below 70 degrees F.
>
> D. If the battery's state-of-charge is at 75% or higher, then load
>test the battery by one of the following methods:
>
> 1. Turn the headlights on high beam for six minutes,
>
> 2. Disable the ignition and turn the engine over for 15
> seconds with the starter motor,
>
> 3. With a battery load tester, apply a load equal to one half
> of the Cold Cranking Amp (CCA) rating of the battery, or
>
> 4. With a battery load tester, apply a load equal to one half
> the Original Equipment Manufacturer (OEM) cranking amp
> specification.
>
>DURING the load test, the voltage on a good battery will NOT drop below
>9.7 volts with the electrolyte at 80 degrees F. (If the electrolyte
>is above 80 degrees, add .1 volt for every 10 degrees above 80 until you
>reach 100 degrees. If below 80 degrees, subtract .1 volt for every 10
>degrees until 40 degrees.) After the load is removed, the battery should
>"bounce back" to the 50% state-of-charge level or above. If the battery
>drops below minimum test voltage, does not bounce back or will not start
>the engine, then you should replace it. If it passes this test, you
>should recharge your battery to restore it to peak performance.
>
>
>4. HOW DO I KNOW IF MY CHARGING SYSTEM IS OK?
>
>When the charging system fails, usually the alternator light will come on.
>With a good battery and the engine running at 2000 RPM or more for two
>minutes, depending on the load and ambient temperature, the voltage will
>increase to between 13.0 and 15.1 volts. Other factors affecting the
>charging voltage are the battery's age, state of charge, and electrolyte
>level and purity. A loose alternator belt will significantly reduce the
>alternator's output.
>
>
>5. HOW DO I JUMP START MY CAR?
>
>This assumes a 12 volt negative grounded system found on almost every car
>in the United States.
>
> A. Determine that the electrolyte is NOT frozen. If frozen, allow
>to thaw.
>
> B. Turn off all unnecessary accessories and lights on both cars.
>
> C. Start the car with the good battery and let it run for at least
>two or three minutes at fast idle BEFORE attempting to start the disabled
>car.
>
> D. Connect the POSITIVE terminal on the disabled battery to the
>POSITIVE terminal on the good battery.
>
> E. Connect the NEGATIVE terminal on the good battery to a clean,
>unpainted area on the ENGINE BLOCK on the disabled car.
>
> F. Let the good car to continue to run for five minutes or more.
>This will allow the dead battery to receive some charge and to warm it's
>electrolyte.
>
> G. Start the disabled car and allow to run at fast idle.
>
> H. Disconnect the jumper cables in the reverse order, starting with
>the ENGINE BLOCK on the disable car.
>
>
>6. WHAT DO I LOOK FOR IN BUYING A NEW BATTERY?
>
> A. Cold Cranking Amps
>
>The most important consideration is the battery's CCA rating. CCAs are
>the discharge load measured in amps that a fully charged battery at 0
>degrees F can deliver for 30 seconds and while maintaining the voltage
>above 7.2 volts. Batteries are sometimes advertised by their Cranking
>Amps (CA) measured at 32 degrees or Hot Cranking Amps (HCA) measured at 80
>degrees, which are not the same as CCA. Do not be mislead by CAs or HCAs.
>To convert CAs to CCAs, multiply the CAs by .8. To convert HCAs to CCAs,
>multiply HCAs by .69. In hot climates, buying batteries with double or
>triple the CCA ratings that exceed the OEM requirement is a WASTE of
>money. However, in colder climates the higher CCA rating the better, due
>to increased power required to crank a sluggish engine and the
>inefficiency of the cold battery. One of the major manufacturers, Exide,
>publishes the following table:
>
> Available Power Temperature Power Required
> From Battery degrees F To Crank Engine
>
> 100% 80 100%
>
> 65% 32 155%
>
> 40% 0 210%
>
> 25% -32 350%
>
> B. Reserve Capacity
>
>The next most important consideration in buying a battery is the Reserve
>Capacity (RC) rating because of the effects of an increased parasitic or
>"key off" load produced by electrical devices, e.g., fans, clocks,
>computers, etc., that operate after the engine is stopped. RC is the
>number of minutes a fully charged battery at 80 degrees F can be
>discharged at 25 amps until the voltage falls below 10.5 volts. More RC
>is better in every case. For example, if your car has a 360 OEM cranking
>amp requirement, then a 450 to 500 CCA rated battery with 120 minute RC
>would be more desirable in a warm climate than one with 700 to 800 CCA with
>90 minutes of RC.
>
> C. Type
>
>A sealed or "maintenance free" battery will NOT allow you to test the
>specific gravity with a hydrometer or add DISTILLED water when required.
>Sealed batteries are more prone to deep discharge failures, but require
>less preventative maintenance. Car batteries are specially designed for
>high initial cranking amps (usually for five seconds) to start a car;
>whereas, deep cycle or "marine" batteries are designed for prolonged
>discharges at lower amperage. A "dual marine" battery is a compromise
>between a car and deep cycle battery. However, a CAR battery will give
>you the best performance in a car. Some manufactures have introduced a
>"dual" battery that combines a standard battery with emergency backup
>cells. For about the same cost a better approach is to buy two batteries
>and isolate them.
>
>
> D. Size
>
>Manufacturers build their batteries to an internationally adopted BCI
>group number (24F, 35, etc.) specification, which is based on the physical
>case size, terminal placement and terminal polarity. The OEM battery
>group number is a good starting place to determine the replacement
>group. Within a group, the CCA and RC ratings, warranty and battery type
>will vary in models of the same brand or from brand to brand. Batteries
>are generally sold by model, so the group numbers will vary for the same
>price. This means that for the SAME price you can potentially buy a
>physically larger battery with more RC than the battery you are replacing.
>Be sure that the replacement battery will fit, the cables will correct to
>the correct terminal, and that the terminals will NOT touch the hood when
>closed.
>
>The battery manufacturers publish application guides that will contain the
>OEM cranking amp and group number replacement recommendations by make,
>model and year of car, and battery size, CCA and RC specifications.
>Manufacturers might not build or the store might not carry all the group
>numbers. To reduce inventory costs, dual terminal "universal" batteries
>that will replace several group sizes are becoming more popular. The four
>largest domestic battery manufacturers are Johnson Controls (Interstate,
>Motorcraft, Energizer, older Diehards), Delco (Sears, newer Diehards), GNB
>(Champion) and Exide (NAPA).
>
> E. Freshness
>
>Determining the "freshness" of a battery is sometimes difficult. NEVER
>buy a battery that is MORE than SIX months old. The date of manufacture
>is stamped on the case or printed on a sticker. It is usually a
>combination of alpha and numeric characters with letters for the months
>starting with "A" for January (skipping "I") and digit for the year, e.g.,
>"F5" for June, 1995. Like bread, fresher is definitely better.
>
> F. Warranty
>
>As with tire warranties, battery warranties are not necessarily indicative
>of the quality or cost over the life of the car. Manufacturers will
>prorate warranties based on the LIST price, so if a battery failed half
>way or more through its warranty period, buying a NEW replacement might
>cost you less. The exception is the free replacement warranty period.
>This represents the risk that the manufacturer is willing to assume. A
>longer free replacement warranty period is better.
>
>
>7. HOW DO I INSTALL A BATTERY?
>
> A. Thoroughly wash and clean the old battery, battery terminals and
>case or tray with water to minimize problems from acid or corrosion.
>Heavy corrosion can be neutralized with a mixture of baking soda and
>water. Auto parts stores sell a cheap wire brush that will allow you to
>clean the inside of a terminal clamps. Mark the positive cable so you do
>not forget which one it is when you reconnect.
>
> B. Remove the NEGATIVE cable first, the POSITIVE cable and then the
>hold-down bracket or clamp. Dispose the old battery by exchanging it when
>you buy your new one or at a recycling center. Batteries contain large
>amounts of lead and acid.
>
> C. After removing the old battery, be sure that the battery tray and
>cable connectors are clean. If the cables are corroded or damaged,
>replace them; otherwise, they will significantly reduce starting
>capability.
>
> D. Place the replacement battery so that the NEGATIVE cable will
>connect to the NEGATIVE terminal. Reversing the polarity of the
>electrical system WILL severely damage it.
>
> E. After replacing the hold-down bracket, reconnect the POSITIVE
>cable first and then the NEGATIVE cable.
>
> F. Before starting the engine, check the electrolyte levels and
>state-of-charge and refill or recharge as required.
>
> G. Coat the terminals with a high temperature grease to prevent
>corrosion.
>
>If you do not want to lose your car's computer memory, security codes or
>radio settings, a second battery can be temporarily connected to the
>electrical system in parallel before disconnecting the first one. A
>cigarette lighter plug can easily connect a parallel battery.
>
>
>8. HOW DO I CHARGE MY BATTERY?
>
>Some more words of caution. Do NOT ever disconnect a battery cable from
>car with the engine running because the battery acts like a filter for the
>electrical system. Unfiltered electricity can damage the electrical
>components, for example, computer, radio, etc. Check the electrolyte level
>before recharging. Do NOT add water if the electrolyte is covering the
>top of the plates because during the recharging process, it will warm up
>and expand. After recharging has been completed and the electrolyte has
>cooled, RECHECK the level and add DISTILLED water to 1/8" BELOW the bottom
>of the filler tube (vent wells) or to the level indicated by the battery
>manufacturer. Reinstall the vent caps before recharging and recharge ONLY
>in well ventilated areas. NO smoking, sparks or open flames because while
>being recharged, batteries give off explosive gasses. If your battery is
>the sealed, do NOT recharge with high current.
>
> A. Usually, a car is jump started and run to recharge the battery,
>which might NOT fully charge it. The length of time to fully recharge the
>battery depends on the amount of discharge, the amount of surplus current
>that is diverted to the battery, how long the engine is run, RPM, and
>temperature. That is, an alternator is sized by the car manufacturer to
>carry the maximum accessory load and maintain a battery, NOT recharge a
>dead one. If you jump start your car, test your battery after you have
>finished driving it, and recharge if the state-of-charge is below 75%.
>
> B. A better method to recharge batteries is to use an external
>constant current charger which is set not to deliver more than 1% of the
>CCA rating of the battery.
>
> C. The best method is to use an external constant voltage or tapered
>current charger. A constant voltage "automatic" charger applies regulated
>voltage at approximately 14.6 volts. A 10 amp automatic charger will cost
>between $30 and $50 at an auto parts store. To prevent damage to the
>battery, the current should be less than 1% of the CCA rating during the
>first 30 minutes. With a taper charger, a high current, up to 30 amps, is
>applied to the battery for a short period up to 30 minutes maximum and
>then is regulated downward until the charge state reaches 100%.
>
>For batteries with a state-of-charge of 25%, the following table,
>published by Interstate Batteries, lists the recommended battery charging
>rates and times:
>
> Reserve Capacity Slow Charge Fast Charge
> (RC) Rating @ 5 Amps @ 20 Amps
>
> 80 Minutes or less 10 Hours 2.5 Hours
>
> 80 to 125 Minutes 15 Hours 4 Hours
>
> 125 to 170 Minutes 22 Hours 5 Hours
>
>If left unattended, cheap, unregulated trickle battery chargers can
>overcharge your battery, because they can "boil off" the electrolyte. Do
>NOT use fast, high rate, or boost chargers on any battery that is sulfated
>or deeply discharged. This condition requires a constant current from one
>to two amps for 60 to 100 hours. The electrolyte should NEVER bubble
>violently while recharging. High currents only create heat and excess
>gas.
>
>
>9. CAN I INCREASE THE LIFE OF MY BATTERY?
>
>Keeping your battery well maintained is the BEST way to extend the life of
>your battery. For cold climates, keeping the battery fully charged and
>warm will help. In the warmer climates and during the summer, the
>electrolyte levels need to be checked more frequently and DISTILLED water
>added, if required. Batteries last approximately two thirds as long in
>hot climates as cold ones. The parasitic load will determine how long a
>car can sit and still be started. Disconnecting the NEGATIVE cable will
>extend the "life" of the battery. Turning off unnecessary accessories and
>lights BEFORE starting your car will decrease the load on the battery
>while cranking. Leaving your lights on and fully discharging the battery
>can ruin it, especially if it is the sealed or maintenance free type.
>Should this occur, you should test the battery after it has been recharged
>to determine if there is permanent damage. NEVER add acid or
>additives--just water.
>
>Maintaining the correct electrolyte levels, tightening loose hold-down
>clamps and terminals, and removing corrosion is normally the ONLY
>preventative maintenance required for a battery.
>
>
>10. WHAT ARE THE MOST COMMON CAUSES OF BATTERY FAILURES?
>
> A. Using an undersized battery,
>
> B. Loss of electrolyte due to heat or overcharging,
>
> C. Overcharging with voltages greater than 15.1 volts,
>
> D. Undercharging,
>
> E. Old age,
>
> F. Vibration,
>
> G. Deep discharges (leaving your lights on),
>
> H. Using tap water,
>
> I. Corrosion,
>
> J. Freezing, and
>
> K. Overheating.
>
>
>11. WHAT ARE SOME OF THE MYTHS ABOUT BATTERIES?
>
> A. Storing a battery on a concrete floor will discharge them.
>
>Modern lead acid battery cases are better sealed, so external leakage
>causing
>discharge is no longer a problem.
>
> B. Driving a car will fully recharge a battery.
>
>There are a number of factors affecting alternator's ability to charge a
>battery. The greatest factors are how much current from the alternator is
>diverted to the battery to charge it, how long the current is available
>and temperature. Generally, short trips during bad weather will not
>recharge the battery; whereas, a long daytime drive in good weather will.
>
> C. A battery will not explode.
>
>While recharging, a battery produces hydrogen and oxygen gasses. If a
>spark occurs, an explosion can occur. Remember the "Hindenburg"!
>
> D. A battery will not lose it's charge sitting in storage.
>
>A battery has internal electrical leakage that will cause it to become
>fully discharged and sulfated over time. Prior to storing a battery, it
>should be fully charged and recharged when it reaches the 50%
>state-of-charge level. Batteries on store shelves should be checked
>periodically and recharged if necessary.
>
> E. Maintenance free battery never requires electrolyte.
>
>In warm climates, the electrolyte could be "boiled off" due to the high
>underhood temperatures. It could also be lost due to excessive charging
>voltage or using high charging currents.
>
>
>Please send comments to Bill Darden at wdarden@mcimail.com.
>
> -------
>
>
>
>
___________________________________
Derek Drew
drew@interport.net (main address for e-mail)
derekdrew@aol.com (alternate/backup address, checked infrequently)
|