While working with lead-acid batteries, please wear glasses to protect your eyes in the unlike event of an explosion.
In a recent marketing study in the U.S., consumers (or non-professional battery installers) installed almost 60% of the approximately 82 million replacement Car batteries that were made in 1999. Car batteries were the fourth most popular item purchased among auto parts. The same study indicated that Wal-Mart (EverStart) has surpassed Sears (DieHard) as the number one car battery seller in the United States with Auto Zone (DuraLast) as the most popular of the U.S. auto parts stores for car batteries.
Below are some questions you need to ask yourself because the installation of a replacement battery and disposal of the old one is usually included in the purchase price at some auto parts and battery stores:
If you decide to proceed, following is a list of easy steps to replace your battery and assumes that there the electrical and charging systems are in good condition:
8.1. Fully charge and test the new battery. (Please see Section 9 for charging and Section 4 for testing the battery.)
8.2. If a non-sealed wet battery, check the electrolyte levels after the battery has reached room temperature and "top off" to the proper level with distilled, deionized or demineralized water as required, but do not over fill. The plates need to be covered with electrolyte at all times to prevent an internal battery explosion or sulfation. Please see Section 3.2 for electrolyte fill levels.
8.3. Thoroughly wash and clean the old battery, battery terminals and tray (case or box) with warm water to minimize problems from acid or corrosion. Please see Section 3.4 for more information on corrosion.
8.4. Mark all of the battery cables so you will know how to reconnect to proper battery post or terminal and check the cables and cable terminals closely for damage. A loose terminal connection, bad crimp or cut cable will cause a high resistance and a large voltage drop when high current is running though it. If the cables are reversed, you can do extensive damage to your electrical system.
8.5. For Car battery installations, to prevent voltage spikes from damaging electronic equipment such as the emissions computer and to save the radio station, em missions computer and security code settings, temporarily connect a second 12-volt battery in parallel to the electrical system before disconnecting the first battery. If active when the key is off, a cigarette lighter plug can be used to easily connect a 12-volt parallel battery. Cigarette lighter adapters are available at electronics stores and "Computer Memory Saver" with a 9-volt battery are available at some auto parts stores, like JC Whitney for about $10.
8.6. Turn off all the electrical switches and breakers and electronic and electrical accessories and appliances. Without using a hammer on the battery cable terminals or posts, remove the NEGATIVE (-) cable first because this will minimize the possibility of shorting the battery when you remove the other cables. Secure the negative cable so that it cannot "spring" loose and make electrical contact. Next remove the POSITIVE (+) cable. Please remember that the battery terminal connector on the end of the POSITIVE (+) battery cable maybe "hot" (or have voltage on it), so put it in a small plastic bag or cloth around it so that it will not touch the metal frame or engine components.
8.7. Carefully lift the old battery out and dispose of it by exchanging it when you buy your new replacement battery or by taking it to a recycling center. For additional information on recycling batteries, go to http://www.batterycouncil.org/recycling.html. Please remember that batteries contain large amounts of harmful lead, acid and other chemicals, so take great care with safety and please dispose of your old battery properly to protect our fragile environment.
8.8. After removing the old battery, insure that the battery tray or box, cable terminals, and connectors are clean. Auto parts or battery stores sell an inexpensive brass wire brush that will clean the inside of post terminal clamps and the post terminals. If the terminals, cables or hold-down brackets are corroded, replace them. A broken hold down bracket will cause excessive battery vibration and that will cause a premature failure. Replace any battery cables that are corroding, swelling or other damage with equal or larger diameter cable. Larger cable is better because there is less voltage drop. Please see Exide's Voltage Drop in Cables for additional information.
8.9. Check the positive and negative terminal markings on the replacement battery and position it so that the NEGATIVE (-) cable will connect to the NEGATIVE (-) terminal. Reversing the polarity of the electrical system can severely damage or destroy it. It can even cause the battery to explode.
8.10. After replacing and tightening the hold-down bracket, remove any plastic caps or covers on the terminals of the replacement battery, and reconnect the cables in reverse order, that is, attach the POSITIVE (+) cable first and the NEGATIVE (-) cable last. For General Motors-type side terminals, check the length of the bolt and do not over tighten, or you could crack the battery case. Connections need to be periodically checked for corrosion (or oxidation) and retightened, including the grounding cables to the vehicle's frame and engine block.
8.11. To prevent corrosion, coat the terminals and exposed metal parts. Please see Section 3.4 for more information on corrosion.
8.12. Remove the parallel battery and rest all the switches and breakers, if required.
8.13. Test the new battery by starting your engine or with an electrical load.
Some vehicles are have battery electrolyte level sensors. For Toyota and Nissan, use the sensor bypass information at http://www.exide.com/products/trans/na/battery_care/toyota_nissan.pdf and for Mazda use http://www.exide.com/products/trans/na/battery_care/toyota_nissan.pdf. A good source of information for measuring maximum cable and connector voltage drops can be found at Exide's Caring For Your Battery
Wire sizing and cable lengths are very important because wiring that is not large enough or different lengths will cause excessive voltage loss and undercharged batteries or, in some cases, a fire. Batteries connected in parallel should have the same cable lengths and size from the charging or discharging source. Use of buss bars are highly recommended for larger deep cycle battery installations. A good source of information of wire sizing can be found at http://www.solarexpert.com/Photowiring.html. Using properly sized fuses or circuit breakers is also very important because they can provide protection for the wiring from over heating and for the electrical appliances. Series, parallel, and series-parallel battery connection wiring diagrams can be found in Section 7.3.2. Connections will need to be periodically retightened. A good source of information on measuring for maximum voltage drops can be found at Exide's Caring For Your Battery.
Insure there is adequate ventilation for the batteries so the gas can dissipate while recharging and the batteries can stay cooler. In other words, do not use sealed battery boxes, even with sealed Gel Cell or AGM VRLA batteries. Some batteries will require up to 30 "preconditioning" cycles before they will produce their rated capacity. This is because the acid needs to fully penetrate the pores of the newly formed plates.