| Subject: | Car Battery FAQ 2.0 |
| Date: | Mon, 16 Sep 1996 20:31:04 -0300 (ADT) |
I had a large response for this, 16+ replies so far. Forgive me all you others but this is easiest way to do it. There is a note on a deep cycle battery FAQ site at the very bottom too, maybe for Westies/solar folks. Tim Smith >--- Forwarded message follows --- >From: wdarden@mcimail.com (William Darden) >Subject: Car Battery Frequently Ask Questions 2.0 >Date: 9 Sep 1996 11:35:14 GMT > > > > CAR BATTERY FREQUENTLY ASKED QUESTIONS 2.0 > September 8, 1996 > > >A word of caution. Batteries contain a sulfuric acid electrolyte which is >a highly corrosive poison, that will produce gasses when recharged and >explode if ignited. This will hurt you--BAD! When working with >batteries, you need to have plenty of ventilation, remove jewelry, wear >protective clothing and eye wear, and exercise caution. Whenever >possible, please follow the manufacturer's instructions for testing, >jumping, installing and charging. This FAQ assumes a six cell, 12 volt >negatively grounded system found in most cars, light trucks or vans. > >The technical stuff is in [brackets]. > > >CONTENTS > > 1. WHAT IS THE BOTTOM LINE? > 2. WHY BOTHER? > 3. HOW DO I PERFORM PREVENTATIVE MAINTENANCE? > 4. HOW DO I TEST A BATTERY? > 5. HOW DO I KNOW IF THE CHARGING SYSTEM IS OK? > 6. HOW DO I JUMP START MY CAR? > 7. WHAT DO I LOOK FOR IN BUYING A NEW BATTERY? > 8. HOW DO I INSTALL A NEW BATTERY? > 9. HOW DO I RECHARGE MY BATTERY? > 10. WHAT IS PARASITIC LOAD? > 11. HOW CAN I INCREASE THE LIFE OF MY BATTERY? > 12. WHAT ARE THE MOST COMMON CAUSES OF PREMATURE BATTERY > FAILURES? > 13. WHAT ARE THE MYTHS ABOUT BATTERIES? > 14. WHERE CAN I FIND MORE INFO ON BATTERIES? > > >1. WHAT IS THE BOTTOM LINE? > > A. Perform regular preventative maintenance, especially during HOT >weather and before COLD weather, (See Section 3) > > B. Remove surface charge before load testing and check the specific >gravity in each cell and the terminal voltage, (See Section 4) > > C. Keep the battery charged, but do NOT overcharge, (See Section 9) > > D. Buy the freshest and largest Reserve Capacity (RC), non-sealed >battery that will physically fit with a Cold Cranking Amp (CCA) rating for >your climate that meets or exceeds the car's Original Equipment >Manufacturer's (OEM) cranking amp requirement, and (See Section 7) > > E. Retest after deep discharges or jump starts for latent damage. >(See Section 4) > > >2. WHY BOTHER? > >Because only the rich can afford cheap batteries..... > >A good quality battery will cost between $50 and $100 U.S. and, if >properly maintained, it should give you an average of five years of >service. The primary purpose of a car battery is to start the engine, >filter or stabilize the power, and provide extra power for the ignition, >lighting and other accessories when their combined load EXCEEDS the >capability of the charging system, i.e., when the engine is idling. >Secondarily, a car battery provides power to the electrical system when >the charging system is not operating. > >A battery "ages" as the active plate material sheds (or flakes off) due >to the expansion and contraction that occurs during the discharge and >recharge cycles. Deep discharges, heat and vibration accelerate this >"aging" process. Eventually, the sediment builds up and the cell shorts >out or the active material in the plates can no longer sustain a discharge >current and the battery "dies". In a hot climate, the harshest >environment for a battery, a recent survey of junk batteries revealed that >the AVERAGE life of a good qualify battery was 37 months, whereas, for a >poor quality battery, it was 23 months. Slow cranking, especially on a >cold day, is another good indication that your battery is going bad and it >should be tested. > >Deeply discharged batteries almost always occur at the most inopportune >times, e.g., AFTER you have jump started your car, at the airport >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 of the "defective" batteries returned to the manufacturer are good. >This suggests that most SELLERS of new batteries do not know how to >properly test batteries. > > >3. HOW DO I PERFORM PREVENTATIVE MAINTENANCE? > >Maintaining the correct electrolyte levels, tightening loose hold-down >clamps and terminals, removing corrosion, and checking the alternator >belt tension is normally the ONLY preventative maintenance required for >a battery. The preventive maintenance frequency is dependent upon climate >and battery type, but you should perform at least once before cold weather >starts and once a month in hot weather. > >If the electrolyte levels are low, add DISTILLED water to the level >indicated by the battery manufacturer or to 1/8" BELOW the bottom of the >filler tube (vent wells). DO NOT OVERFILL, especially in hot climates! > > >4. HOW DO I TEST A BATTERY? > >The are four simple steps to test a car battery--inspection, remove >surface charge, state-of-charge test and load test. To test a battery >(or to troubleshoot charging or electrical systems), you will need a >digital voltmeter with .5% or better accuracy. A digital voltmeter can be >purchased at an electronics store and will cost between $20 and $200 U.S. >If you have a non-sealed battery, you will need a temperature compensating >hydrometer which can be purchased at an auto parts store for approximately >$5 U.S. > > A. INSPECTION > >Visually inspect for obvious problems, e.g., loose alternator belt, low >electrolyte, corroded cable or terminal clamps, loose hold-down clamps or >cable terminals, or a damaged case. > > B. REMOVE SURFACE CHARGE > >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 five minutes and > wait five minutes, or > > 3. With a battery load tester, apply a load at one half the > battery's CCA rating for 15 seconds and wait five minutes. > > C. STATE-OF-CHARGE TEST > >Using the following table, determine the battery's state-of-charge: > > Open Circuit Approximate Average Cell > Battery Voltage State-of-charge Specific Gravity > > 12.65 100% 1.265 > > 12.45 75% 1.225 > > 12.24 50% 1.190 > > 12.06 25% 1.155 > > 11.89 0% 1.120 > >[If the temperature of the electrolyte is below 70 degrees F (21.1 degrees >C), then add .012 volts (12 millivolts) per degree below 70 degrees F to >the reading.] > >Check both the specific gravity in each cell with a external hydrometer >AND the battery terminal voltage with a digital voltmeter without the >engine running. For sealed batteries, measuring the battery's voltage >without the engine running with a digital voltmeter is the only way you >can determine the state-of-charge. Some batteries have a built-in >hydrometer which only measures the state-of-charge in ONE of it's six >cells. If the indicator is clear or light yellow, then the battery has a >low electrolyte level and should be refilled before proceeding, or if >sealed, the battery should be replaced. > >If the state-of-charge is BELOW 75% using either the specific gravity or >voltage test or the built-in hydrometer indicates "bad" (usually dark), >then the battery needs to be recharged BEFORE proceeding. Replace the >battery, if one or more of the following conditions occur: > > 1. If there is a .050 or more difference in the specific > gravity reading between the highest and lowest cell, you > have a weak or dead cell(s), > > 2. If the battery will not recharge to a 75% or more > state-of-charge level or if the built-in hydrometer still > does not indicate "good" (usually green, which is 65% > state-of-charge or better), > > 3. If digital voltmeter indicates 0 volts, you have an open > cell, or > > 4. If the digital voltmeter indicates 10.45 to 10.65 volts, > you have a shorted cell. [A shorted cell is caused by > plates touching, sediment build-up or "treeing" between > plates. > > D. LOAD TEST > >If the battery's state-of-charge is at 75% or higher or has a "good" >built-in hydrometer indication, then load test the battery by one of the >following methods: > > 1. Turn the headlights on high beam for five 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 CCA rating of the battery for 15 seconds, or > > 4. With a battery load tester, apply a load equal to one half > the OEM cranking amp specification for 15 seconds. > >DURING the load test, the voltage on a good battery will NOT drop below >9.7 volts with the electrolyte at 80 degrees F (26.7 degrees C). [If the >electrolyte is above 80 degrees F, add .1 volt for every 10 degrees above >80 until you reach 100 degrees. If below 80 degrees F, subtract .1 volt >for every 10 degrees until 40 degrees.] After the load is removed, wait >five minutes and 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 the battery passes this test, you should recharge >it to restore it to peak performance. > > >5. HOW DO I KNOW IF MY CHARGING SYSTEM IS OK? > >A car's charging system is composed of an alternator (or DC generator), a >voltage regulator, battery and indicator light or gauge. While the engine >is running, it's purpose is to provide power for the car's electrical >load, e.g., ignition, lighting, accessories, etc., and to recharge the >car's battery. > >When the charging system fails, usually an indicator light will come on or >the gauge will not register "good". The most common charging system >failure is a loose, worn or broken alternator belt, so check it first. If >OK, then with a known good battery and the engine running at 2000 RPM or >more for two minutes, depending on the load and ambient temperature, the >voltage should increase to between 13.0 and 15.1 volts. Most cars will >measure between 14.0 and 14.5 volts on a warm day. [Most voltage >regulators are temperature compensated to properly charge the battery >under different environmental conditions. As the ambient temperature >decreases, the charging voltage is increased to overcome the higher >battery resistance. Conversely, as the ambient temperature increases, >the charging voltage is reduced. Other factors affecting the charging >voltage are the battery's condition, state-of-charge, electrical load and >electrolyte level and purity.] > >If terminal voltage is below 13.0 volts and the battery tests good after >being externally recharged or if you are still having problems keeping it >charged, then have the charging system's output voltage and current and >car's parasitic (key off) load tested. A loose alternator belt or bad >diode will significantly reduce the alternator's current output. > >If output voltage is above 15.1 volts with the ambient temperature above >freezing, the battery's electrolyte level is frequently low, or you smell >"rotten eggs" around the battery, then you are probably overcharging the >battery and the charging system should be tested. > > >6. HOW DO I JUMP START MY CAR? > >In cold weather, a good quality booster cable with four to six gauge wire >is necessary to provide enough current to the disabled car to start the >engine. [The smaller the wire gauge number, i.e., the larger the wire >diameter, the better.] Please check the owner's manual for BOTH vehicles >BEFORE attempting to jump start and follow the manufacturer's procedure >because some cars should not be running during a jump start. However, >starting the disabled car with the good car running can prevent having >two disabled. DO NOT allow the booster cable clamps touch each other or >the POSITIVE clamp to touch the frame or engine block. > > A. If BELOW freezing, determine that the electrolyte is NOT frozen >in the dead battery. If frozen, allow to thaw BEFORE proceeding. A >discharged battery, i.e., battery voltage or 12.0 volts or less or >specific gravity of 1.140 or less, will freeze at approximately 8 >degrees F (-15 degrees C). > > B. Without the cars touching, turn off all unnecessary accessories >and lights on BOTH cars and insure there is plenty of ventilation. > > C. Start the car with the good battery and let it run for at least >two or three minutes at fast idle to recharge it's battery BEFORE >proceeding. > > D. Connect the POSITIVE booster cable clamp (usually RED) to the >POSITIVE terminal on the dead battery. Connect the POSITIVE booster >cable clamp on the other end of the booster cable to the POSITIVE terminal >on the good battery. > > E. Connect the NEGATIVE booster cable clamp (usually BLACK) to the >NEGITIVE terminal on the good battery and the NEGATIVE booster cable clamp >on the other end to a clean, unpainted area on the engine block or frame >on the disabled car AWAY from the battery. > > F. Let the good car to continue to run at high idle for five minutes >OR MORE to allow the dead battery to receive some recharge and to warm >it's electrolyte. > > G. Start the disabled car and allow to run at high idle. If the car >does not start the first time, recheck the connections, wait a few minutes >and try again. > > H. Disconnect the booster cables in the REVERSE order, starting with >the NEGITIVE clamp on the block or frame of the disabled car to minimize >the possibility of an explosion. > > I. As soon as possible, fully recharge and test the dead battery >for latent or permanent damage as a result of the deep discharge. > > >7. WHAT DO I LOOK FOR IN BUYING A NEW BATTERY? > >Battery buying strategy for use in Canada, for example, is different than >hot climates that you find in Texas. In the colder climates, higher CCA >ratings are more important; whereas, in a hot climate, a higher RC ratings >are more important once the CCA rating has satisfied the OEM cranking amp >requirement. > > A. Cold Cranking Amps (CCA) > >The most important consideration is sizing the battery's CCA rating to >MEET OR EXCEED, depending on the climate, the car's OEM cranking >requirement. [CCAs are the discharge load measured in amps that a fully >charged battery at 0 degrees F (-17.8 degrees C) can deliver for 30 >seconds and while maintaining the voltage above 7.2 volts. Batteries are >sometimes advertised by their Cranking Performance Amps (CA) or Marine >Cranking Amps (MCA) measured at 32 degrees F (0 degrees C) or Hot Cranking >Amps (HCA) measured at 80 degrees F (26.7 degrees C), which are not the >same as CCA. Do not be mislead by CA, MCA or HCA ratings. 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. As batteries age, they are less capable of producing CCAs. > >One of the major battery 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% > >[If more CCA capacity is required, two (or more) 12 volt batteries can be >connected in parallel. Within a BCI group size, generally the battery >with more CCA will have more plates because a larger surface area is >required to produce the higher current.] > > B. Reserve Capacity (RC) > >The second most important consideration is the Reserve Capacity rating >because of the effects of an increased parasitic (key off) load and in >emergencies. [RC is the number of minutes a fully charged battery at 80 >degrees F (26.7 degrees C) can be discharged at 25 amps until the voltage >falls below 10.5 volts.] More RC is better in every case! In a hot >climate, for example, if your car has a 360 OEM cranking amp requirement, >then a 400 CCA rated battery with 120 minute RC with more electrolyte >would be more desirable than one with 1000 CCA with 90 minutes of RC. > >[If more RC is required, two six volt batteries can be connected in series >or two (or more) 12 volt batteries can be connected in parallel. Within a >BCI group size, generally the battery with larger RC will weigh more >because it contains more lead.] > > C. Type > >The two most common types of CAR batteries are low maintenance >(non-sealed) and maintenance free (non-sealed or sealed). [The low >maintenance batteries have a lead-antimony/calcium (dual alloy or hybrid) >plate formulation; whereas, the maintenance free batteries have a >lead-calcium/calcium formulation.] The advantages of maintenance free >batteries are less preventative maintenance, longer life, faster >recharging, greater overcharge resistance, reduced terminal corrosion and >longer shelf life, but are more prone to deep discharge (dead battery) >failures. In hot climates, buying non-sealed batteries is recommended >because a sealed battery will NOT allow you to add water when required or >to test the specific gravity with an external hydrometer. > >Some manufacturers introduced a third type of car battery, "dual", that >combined a standard battery with switchable emergency backup cells. For >about the same cost a better approach was to buy two batteries and isolate >them. > >For off road applications in trucks, recreational vehicles (RVs), 4x4s, >vans or sport utility vehicles, some manufacturer's distribute "high >vibration" or RV battery versions designed to reduce the effects of >moderate vibration. For excessive vibration applications, it is best to >buy a commercial battery. > >Car batteries are specially designed for high initial cranking amps >(usually for five to 15 seconds) to start an engine; 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. For RVs, a car battery is used to start the engine and a deep >cycle battery is used to power the accessories. [The batteries are >connected to a diode isolator and both are automatically recharged by the >RV's charging system when engine is running. For additional information >on multi-battery applications, call (800) 845-6269 or (503) 692-5360 and >request a free copy of "Introduction to Batteries and Charging Systems" by >Ralph Scheidler.] > > D. Size > >Manufacturers build their batteries to an internationally adopted Battery >Council International (BCI) group number (24, 26, 70, 75, 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, e.g. a 34/78 group might >replace a smaller 26/70 group and give you an additional 30 minutes of RC. >If you do this, be sure that the replacement battery will fit, the cables >will connect to the correct terminals, and that the terminals will NOT >touch the hood when closed. > >BCI and the battery manufacturers publish application guides that will >contain the OEM cranking amperage requirements 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 BCI group numbers. To reduce inventory >costs, dual terminal "universal" batteries that will replace several group >sizes are becoming more popular and fit 75% or more of cars on the road >today. > >Battery manufacturers or distributors will often "private label" their >batteries for large chain stores. Below is a list of the largest domestic >battery manufacturers/distributors in North America and my understanding >of some of their brand names and private labels. > > Johnson Controls Inc. (JCI) > Ameriton > Duralast (Contact local Auto Zone store) > Energizer (Contact local Target store) > Eveready (800-331-9926 or contact local Costco store) > Interstate (800-272-6548) > Motorcraft (800-392-3673) > Power Connection > older Sears Diehards > > East Penn (610-682-6361) > American > Electro > Deka > Hi-Tech > Pow-R-Surge > > Douglas (800-368-4527) > Farmland (Contact local store) > > AC Delco/Delphi (800-223-3526) > Diehard Gold (Contact local Sears store) > Double Eagle (Contact local Firestone store) > Dura Power > Everstart (Contact local Wal-Mart store) > Freedom (Contact local Sears store) > Lastcell (Contact local Trac Auto store) > Tough One (Contact local Western Auto store) > Voyager > > GNB (800-242-6750) > Champion (Contact local Sams store) > Omaga (800-925-6278 or contact local Wal-Mart store) > Voyager (Contact local Sams store) > > Exide (800-346-3760) > Auto Express (Contact local Wards store) > Centura (Contact local K-Mart store) > DieHard non-Gold (Contact local Sears store) > Edge > Legend (800-538-6272 or contact local NAPA store) > Motorvator (Contact local K-Mart store) > Power-Tron > Prestolite (Contact local HiLo store) > Pro Start (Contact local Pep Boys store) > Quick Start (Contact local Wards store) > Sears (Contact local store) > Titan > Value-Lite (Contact local Firestone store) > > E. Freshness > >Determining the "freshness" of a battery is sometimes difficult. NEVER >buy a battery that is MORE than SIX months old because it is starting to >sulfate. [Sulfation occurs when lead sulfate can not be converted back to >charged material and is created when discharged batteries stand for a long >time or from excessive water loss.] 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., "J6" for September, >1996. 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. Most manufacturers will >prorate warranties based on the LIST price of the bad and replacement >battery, so if a battery failed half way or more through its warranty >period, buying a NEW battery outright might cost you less than paying the >difference under a prorated warranty. The exception to this 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 and is usually an indication of the quality of the >battery. > > >8. HOW DO I INSTALL A BATTERY? > >A car battery weights between 30 and 60 pounds, so the first question is >do I want to install it myself? The second question is what do I do with >the old battery if not exchanged for the new one? > > 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. Also, mark the cables so you do not forget which one it is which >when you reconnect. > > B. Remove the NEGATIVE cable first because this will minimize the >possibility of shorting the battery when you remove the other cable. >Next remove the POSITIVE cable and then the hold-down bracket or clamp. >If the hold down bracket is severely corroded, replace it. Dispose the >old battery by exchanging it when you buy your new one or by taking it to >a recycling center. Please remember that batteries contain large amounts >of harmful lead and acid. > > C. After removing the old battery, be sure that the battery tray >and cable terminals or connectors are clean. Auto parts stores sell a >cheap wire brush that will allow you to clean the inside of a terminal >clamps and the terminals. If the terminals, cables or hold down brackets >are severely corroded, replace them. Corroded terminals or cables will >significantly reduce starting capability. > > D. Thinly coat the terminal and terminal clamps with a high >temperature grease or petroleum jelly (Vaseline) to prevent corrosion. > > E. 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 or DESTROY it. > > F. After replacing the hold-down bracket, reconnect the cables in >reverse order, i.e., attach the POSITIVE cable first and then the NEGATIVE >cable last. > > G. Before starting the engine, check the electrolyte levels and >state-of-charge. Refill or recharge as required. > > [If you want to retain 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 used to easily connect a parallel battery.] > > >9. HOW DO I RECHARGE MY BATTERY? > >In addition to the earlier cautions, some more words of caution: > > A. NEVER, NEVER disconnect a battery cable from car with the engine >running because the battery acts like a filter for the electrical system. >Unfiltered [pulsating DC] electricity can damage expensive electrical >components, e.g., computer, radio, charging system, etc. > > B. Check the electrolyte level and be sure it is not frozen BEFORE >recharging. > > C. 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, RECHECK the level. > > D. Reinstall the vent caps BEFORE recharging and recharge ONLY in >well ventilated areas. NO smoking, sparks or open flames because while >the battery is being recharged because they give off explosive gasses. > > E. If your battery is sealed, do NOT recharge with current ABOVE 25 >amps. > > F. Follow the charger manufacturer's procedures for connecting and >disconnecting cables and operation to minimize the possibility of an >explosion, but generally you should turn the charger OFF before connecting >or disconnecting cables to a battery. > > G. If a battery becomes hot, or if violent gassing or spewing of >electrolyte occurs, turn the charger off temporarily or reduce the >charging rate. > > H. Insure that in car charging with an external charger will not >damage the car's electrical system with high voltages. If this is even a >remote possibility, then disconnect the car's negative battery cable from >the battery BEFORE connecting the charger. > >Usually, a when car is jump started, it is run to recharge (or equalize) >the battery. This 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. > >[For example, if 300 amps are consumed for ten seconds to start a car from >a fully charged battery, it will take the charging system approximately >two and one half minutes to replace the power used if 25 amps are >available to the battery, or six minutes at ten amps, and an hour at one >amp. Using the same example with a dead 120 minute RC battery, it would >take approximately 86 times longer to recharge it or three and one half >hours at 25 amps, 8.7 hours at 10 amps or 86.4 hours at one amp]. > >If you have added lights, audio amplifiers, alarms, cellular telephones or >other accessories, and "stop-and-go drive occurs frequently, the >alternator might NOT produce enough current to keep your battery fully >charged. You might need to increase the capacity of the charging system. >[Ideally the combined load of all the lights, fans, and accessories >should be less than 75% of the charging system's maximum output, so that >at least 25% is available to recharge the battery.] > >A better method to recharge batteries is to use an external constant >current charger which is set not to deliver more than 12% of the RC rating >of the battery and monitor the state-of-charge. For fully discharged >batteries, the following table, published by BCI, lists the recommended >battery charging rates and times: > > Reserve Capacity Slow Charge Fast Charge > (RC) Rating > > 80 Minutes or less 15 Hours @ 3 amps 2.5 Hours @ 20 amps > > 80 to 125 Minutes 21 Hours @ 4 amps 3.75 Hours @ 20 amps > > 125 to 170 Minutes 22 Hours @ 5 amps 5 Hours @ 20 amps > > 170 to 250 Minutes 23 Hours @ 6 amps 7.5 Hours @ 20 amps > > Above 250 Minutes 24 Hours @ 10 amps 6 Hours @ 40 amps > >The BEST method is to SLOWLY recharge it using an external constant >voltage (or tapered current charger) because the electrolyte has more time >to penetrate the plates. A constant voltage "automatic" charger applies >regulated voltage at approximately 14.4 volts. A 10 amp automatic charger >will cost between $30 and $60 U.S. at an auto parts store. [To prevent >damage to a fully discharged 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, can be applied to non-sealed batteries for a >short period up to 30 minutes maximum and then is regulated downward until >the charge state reaches 100%. > >[An excellent automatic constant voltage battery charger is a 15 volt >regulated power supply adjusted to 14.4 volts at 80 degrees F (26.7 >degrees C). If 32 degrees F (0 degrees C), then increase the charging >voltage to 15.3 volts. When charging a maintenance free battery, add .2 >volts.] > >If left unattended, a 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 120 hours. The electrolyte should NEVER bubble >violently while recharging because high currents only create heat and >excess explosive gasses. > > >10. WHAT IS PARASITIC LOAD? > >Parasitic (key off) is the cumulative load produced by electrical devices, >e.g., clocks, computers, alarms, etc., that operate after the engine is >stopped. Parasitic loads typically run 20 to 120 milliamps. To test the >parasitic load an amp meter must be inserted in series with either the >positive or negative battery terminal and it's cable without the engine >running. If the parasitic load is prematurely discharging your battery, >start removing fuses one-at-a-time until the offending electrical >component is identified. Leaving your headlights on will generally >discharge a fully charged battery (with 90 minutes of RC) in four to six >hours. > > >11. CAN I INCREASE THE LIFE OF MY BATTERY? > > A. Keeping your battery and engine well maintained is the BEST way >to extend the life of your battery. > >For cold climates, keeping the battery fully charged and the engine warm >will help increase the life of the battery. In the warmer climates and >during the summer, the electrolyte levels need to be checked more >frequently and DISTILLED water added, if required. This is due to the >high underhood temperatures. In a study conducted by the Society of >Automotive Engineers (SAE), the underhood temperature have increased 30% >since 1985. Heat shields are becoming more popular and are being used by >a number of car manufacturers to protect the batteries from the high >underhood temperatures. Some battery manufacturers build "hot climate" >versions by increasing the amount of electrolyte in the battery to provide >more "cooling" or by special plate formulations. Batteries last >approximately two thirds as long in hot climates as cold ones. > > B. Add distilled water--NEVER add acid or tap water and DO NOT >OVERFILL. > > C. Turning off unnecessary accessories and lights BEFORE starting >your car will decrease the load on the battery while cranking, especially >when it is cold. > > D. Leaving your lights or other accessories on and fully >discharging the battery can ruin your car battery, especially if it is >maintenance free. If this should this occur, you should test the battery >AFTER it has been fully recharged to determine if there is any latent or >permanent damage. > > E. Reduce the parasitic (key-off) load to 120 milliamps or less. > > F. Storing batteries in cool locations and periodically recharging >them. > > G. In cold climates, increasing the diameter (smaller wire gauge) of >the battery cables will increase the power available to the starter motor. > > >12. WHAT ARE THE MOST COMMON CAUSES OF PREMATURE BATTERY FAILURES? > > A. Loss of electrolyte (which account for over 50% of the failures) >due to underhood heat or overcharging, > > B. Deep discharges (leaving your lights on), > > C. Misapplication or using an undersized battery, > > D. Undercharging or loose alternator belt, > > E. Excessive vibration (due to a loose holdown clamp), > > F. Using tap water, > > G. Corrosion, and > > H. Freezing. > > >13. 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. [Temperature stratification >within large batteries can accelerate the internal "leakage" or self >discharge if the battery is sitting on an extremely cold floor in a warm >room or installed in a submarine.] > > 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, running the engine at idle or short >"stop-and go trips" during bad weather at night will not recharge the >battery. > > C. A battery will not explode. > >While spark retarding vent caps help, 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 self discharge or internal electrochemical "leakage" that >will cause it to become fully discharged and sulfated over time. Prior to >storing a battery, it should be fully charged, placed in a cool location >above freezing, and recharged when it reaches the 50% state-of-charge >level or once every six months, whichever occurs first. If left in a car >or RV, disconnect the negative cable. > > E. Maintenance free batteries never requires electrolyte. > >In hot climates, the electrolyte could be "boiled off" due to the high >underhood temperatures . Electrolyte could also be lost due to excessive >charging voltage or charging currents. > > F. Test the alternator by disconnecting the battery with the engine >running. > >A battery as like a voltage stabilizer or filter to the pulsating DC >produced by the alternator. Disconnecting a battery while the engine is >running can destroy the electronic components, e.g., computers, radio, >stereo, alarm system, etc., or the charging system. Just say NO! if >anyone suggests this. > > >14. WHERE CAN I FIND MORE INFO ON BATTERIES? > >AC Delco Counterman Training Program, www.apaa.org/delco/internet.html. > >AC Delco Home Page, www.apaa.org/delco. > >"Auto Batteries", Consumer Reports, October, 1991. > >"Automotive Battery FAQ", Exide Batteries, http://204.170.84.25/power > /autofaq.htm. > >"Automotive Electrical Troubleshooting Manual", Interstate Batteries, > Dallas. > >"Batteries", Consumer Reports, February, 1987. > >"Battery Replacement Data Book", Battery Council International, Chicago, > 1996. > >"Battery Service Manual", Battery Council International, Chicago. > >"Battery Training Guide", Exide, Reading, PA. > >"Best Bet in Auto Batteries", Consumer Reports, October, 1995. > >Darden, William E., "Deep Cycle Battery FAQ", http: > //nyquist.ee.ualberta.ca/~schmaus/dcbat.html. > >Electrochemical Science and Technology Information Resource Home Page, www.cmt.anl.gov/estir/info.htm. > >Exide Battery Home Page, 205.170.84.25/power/exidepg5.htm. > >"First Aid for an Auto Battery", Consumer Reports, November, 1995. > >Hawkins, Tim, "Batteries: Playing Pinball with Atoms", Nuts & Volts > Magazine, November, 1995. > >Interstate Batteries Home Page, www.interstatebatteries.com. > >Johnson Controls Inc. Home Page, www.jci.com. > >Lead Acid Batteries Home Page, www.ncf.carleton.ca/~bf250/leadacid.html. > >Scheidler, Ralph E., "Introduction to Batteries and Charging Systems", > Sure Power Systems, Tualatin, OR. > >Sci.chem.electrochem.battery, USEnet Newsgoup. > > >Comments are always welcomed by Bill Darden at wdarden@mcimail.com or >(214) 361-9566. For additional information on deep cycle batteries, the >Deep Cycle Battery FAQ maybe found on the Web server at >nyquist.ee.ualberta.ca/~schmaus or by requesting one via email from >wdarden@mcimail.com. > > ------- > >
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