See Figures 1, 2 and 3
Loose, dirty, or corroded battery terminals are a major cause of "no-start.'' Every 3 months or so, remove the battery terminals and clean them. This will help to retard corrosion.
Check the battery cables for signs of wear or chafing and replace any cable or terminal that looks marginal. Battery terminals can be easily cleaned and inexpensive terminal cleaning tools are an excellent investment that will pay for themselves many times over. They can usually be purchased from any well-equipped auto store or parts department. Side terminal batteries require a different tool to clean the threads in the battery case. The accumulated white powder and corrosion can be cleaned from the top of the battery with an old toothbrush and a solution of baking soda and water.
Unless you have a maintenance-free battery, check the electrolyte level and the specific gravity of each cell. Be sure that the vent holes in each cell cap are not blocked by grease or dirt. The vent holes allow hydrogen gas, formed by the chemical reaction in the battery, to escape safely.
FLUID LEVEL (EXCEPT MAINTENANCE-FREE BATTERIES)
See Figure 4
Check the battery electrolyte level at least once a month, or more often in hot weather or during periods of extended car operation. The level can be checked through the case on translucent polypropylene batteries; the cell caps must be removed on other models. The electrolyte level in each cell should be kept filled to the split ring inside, or the line marked on the outside of the case.
If the level is low, add only distilled water, or colorless, odorless drinking water, through the opening until the level is correct. Each cell is completely separate from the others, so each must be checked and filled individually.
If water is added in freezing weather, the car should be driven several miles to allow the water to mix with the electrolyte. Otherwise, the battery could freeze.
SPECIFIC GRAVITY (EXCEPT MAINTENANCE-FREE BATTERIES)
At least once a year, check the specific gravity of the battery using a hydrometer.
A hydrometer, is an inexpensive instrument available from many sources, including auto parts stores. The hydrometer has a squeeze bulb at one end and a nozzle at the other. Battery electrolyte is sucked into the hydrometer until the float is lifted from its seat. The specific gravity is then read by noting the position of the float. Generally, if after charging, the specific gravity between any two cells varies more than 50 points (0.50), the battery is bad and should be replaced.
It is not possible to check the specific gravity in this manner on sealed (maintenance-free) batteries. Instead, the indicator built into the top of the case must be relied on to display any signs of battery deterioration. If the indicator is dark, the battery can be assumed to be OK. If the indicator is light, the specific gravity is low, and the battery should be charged or replaced.
Once every 6 months, the battery terminals and the cable clamps should be cleaned. Loosen the clamps and remove the cables, negative cable first. On batteries with posts on top, the use of a puller specially made for this purpose is recommended. Damage may occur to the battery if proper terminal pullers are not used. These are inexpensive, and available in auto parts stores. Side terminal battery cables are secured with a bolt, and do not require a puller.
Clean the cable clamps and the battery terminal with a wire brush, until all corrosion, grease, etc. is removed and the metal is shiny. It is especially important to clean the inside of the clamp thoroughly, since a small deposit of foreign material or oxidation there can prevent a sound electrical connection and inhibit starting and/or charging. Special tools are available for cleaning these parts, one type for conventional batteries and another type for side terminal batteries.
Before installing the cable, loosen the battery hold-down clamp or strap, remove the battery and check the battery tray. Clear it of any debris, and check it for soundness. Rust should be wire brushed away, and the metal given a coat of anti-rust paint. Before replacing the battery, wash it with soap and water to remove any dirt. Replace the battery and tighten the hold-down clamp or strap securely, but be careful not to overtighten, which will crack the battery case.
After the clamps and terminals are clean, reinstall the cables, negative cable last; do not hammer on the clamps to install. Tighten the clamps securely, but do not distort them. Give the clamps and terminals a thin external coat of grease after installation, to retard corrosion.
Check the cables at the same time that the terminals are cleaned. If the cable insulation is cracked or broken, or if the ends are frayed, the cable should be replaced with a new cable of the same length and gauge.
Keep flames and sparks away from the battery; it gives off explosive hydrogen gas. Battery electrolyte contains sulfuric acid. If you should splash any on your skin or in your eyes, flush the affected areas with plenty of clear water; if it lands in your eyes, get medical help immediately.
Before recharging a battery, see if any of the following problems exist:
If any of these exist, remedy the problem, then check to see if the battery still needs to be charged. Cold batteries will not readily accept a charge. Therefore, batteries should be allowed to warm up to approximately 41°F (5°C) before charging. This may require allowing the battery to warm up at room temperature for four to eight hours, depending on the initial temperature and the size of the battery. A battery which has been completely discharged may be slow to accept a charge initially, and in some cases may not accept a charge at the normal charger setting. When batteries are in this condition, charging can be started by using a dead battery switch, on chargers equipped with one.
Completely discharged batteries, which have been discharged for a prolonged period of time (over one month) or which have an open circuit voltage of less than two volts, may not indicate accepting a charge even when the dead battery switch is used. The initial charge rate accepted by batteries in this condition is so low, that the ammeter on some charges will not show any indication of charge for up to 10 minutes. To determine whether a battery is accepting a charge, follow the charger manufacturer's instructions for the use of the dead battery switch. If the dead battery switch is the spring-loaded type, it should be held in the ON position for up to three minutes.
After releasing the dead battery switch and with the charger still on, measure the battery voltage. If it shows 12 volts or higher, the battery is accepting a charge and is capable of being recharged. But, it may require up to two hours of charging on batteries colder than 41°F (5°C) before the charge rate is high enough to register on the charger ammeter. If a battery cannot be charged by this procedure, it should be replaced.
Once the battery has begun to accept a charge, it can be charge to serviceable state or full charge by one of two methods:
The total charge necessary will vary with battery size and its initial state of charge. In general, to bring a discharged battery to a serviceable state of charge, the amount of charging current multiplied by the charging time should equal the battery amp-hour capacity. For example, a 45 AH battery will need 15 amps of charge for three hours, or 9 amps of charge for five hours. If a full state of charge is desired, the charge can be completed by a low constant current of 3-5 amps for several hours.
See Figure 5
The cold power rating of a battery measures battery starting performance and provides an approximate relationship between battery size and engine size. As a general rule, the cold power rating of a replacement battery should match or exceed your engine size in cubic inches.
- Carefully disconnect the negative battery cable from the battery terminal, and position it aside.
- Carefully disconnect the positive cable from the battery terminal, and position it aside.
- Clean the cable terminals using an acid neutralizing solution and a terminal cleaning brush.
- Remove the battery hold-down clamp(s) by disconnecting the retaining nut(s) and bolt(s).
- Remove the battery.
- Clean the battery tray and hold-down clamp(s) with a wire brush and scraper. Replace any components that are worn.
- Place the battery in the battery tray making sure that the positive and negative terminals are in the same position as they were previous to removal.
- Assemble and tighten the hold-down hardware so that the battery is secure. Do not overtighten.
For some vehicles, when the battery is disconnected and reconnected, abnormal driving symptoms may temporarily occur. The reason for this is that the Powertrain Control Module (PCM) has to relearn its adaptive strategy. Your vehicle may have to be driven 10 miles or more for the module to relearn the strategy.
- Secure the positive, then the negative battery cables to the proper terminals. Do not overtighten.