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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)


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