A battery must provide emergency power for ignition, lights, etc in the event of failure in the vehicles battery recharging system.

The Battery Council International (BCI) defines Reserve Capacity as "the number of minutes a new, fully charged battery at 80 degrees Fahrenheit (26.7 degrees Celcius) can be discharged at 25 amperes and maintain a voltage of 1.75 volts per cell (10.5 volts for a 12 volt battery) or higher."

The primary function of the battery is to provide power to crank the engine during starting at under low temperature condition. The Battery Council International defines CCA as "the discharge load in amperes which a new, fully charged battery at 0 degrees Fahrenheit (-17.8 degrees Celcius) can deliver for 30 seconds and maintain a voltage of 1.2 volt per cell (7.2 volts for a 12-volts battery) or higher".

CA or Cranking Amps is the discharge load in amperes that a new, fully battery at 32 degrees Fahrenheit (0 degrees Celsius) can continuously deliver for 30 seconds while maintaining a terminal voltage equal to or higher than 1.20 volts per cell. The CA rating of a battery may be 10 % to 30 % higher than its CCA rating. The Battery Council International (BCI) does require that, when a battery carries a statement of its CA performance, it must also carry a statement, in equal prominence, of its CCA capacity .

Normally, It need periodically check the battery. Clean the terminals and the cables if they look dirty or corroded. The top of the battery should also be kept clean of heavy dirt and oil accumulation to prevent low - grade short circuiting .

Some batteries are equipped with removable pods or vents so that the electrolyte level in each cell can be checked and filled with water if the level is low. Always use good quality distilled water to prevent iron or other chemical contamination which could drastically reduce the battery's life and power. Be careful not to overfill (past the end of the fill well barrels) or acid may be pumped or expelled during operation or charging .

If your vehicle has set unused for an extended period of time (a month or more), you should recharge the battery before using .

Ten years ago, original equipment batteries are bigger in external size than now. It mean battery technology has advanced significantly over the year, so their ratings are higher .

The new consolidated lines simply take advantage of current technology by substituting these newer, more compact group sizes for older and physically larger "regular" battery group sizes .

Given current technology there is, of course, an upper limit to the amount of power any given external geometry can deliver

- Supply power to the starter and ignition system .
- Supply the extra power required when the vehicle's electrical load requirement exceed the supply from the charging   system .
- Act as a voltage stabilizer in the electrical system. You should not use a battery with rating lower than which the   vehicle manufacturer recommends. In fact, going to a higher rating will improve starting ease for older vehicle and, in   general, provide longer battery life .

Heat causes higher rates of self - discharge and accelerates positive - plate grid corrosion inside the battery. Reduce life of battery. Heat also increases evaporative water losses from the electrolyte. Battery capacity is greatly reduced at low temperature because the chemical reaction slows down significantly and electrolyte resistance increases. At 0 degrees Fahrenheit (-17 degrees Celcius), a battery will only deliver about 40 % of the power it would at 80 degrees Fahrenheit (26.7 degrees Celcius).

There are no Significant long - term effect, however, electrolyte can freeze if the battery is in a discharged state and cause damage to the plates or crack the container. For example, electrolyte at 1.160 specific grafity (a battery which as about 55 % discharged) will freeze at 0 degrees Fahrenheit (-17.8 degrees Celcius). Batteries at usable states of charge will not freeze at temperature above -20 degrees Fahrenheit (-28.9 degrees Celcius).

Each is important and they are interrelated. To understand this better, we must look at what happens when a vehicle is started. in order for starting current to flow, the battery voltage (the pressure which causes the current to flow) must be at or above a minimum level, and the electrical circuit must be complete (ignition switch on). As current is withdrawn, the battery's voltage decays slowly at first (after the initial instantaneous drop) and the more rapidly as the discharge continuous. Normally the engine fires and runs within a couple of seconds without sustained or repeated cranks .

The load (work) required to crank the engine determines how much current the starter will draw. It draws only what it needs regardless of the excess CCA capacity the battery may have.

If the engine doesn't fire and run and if cranking is sustained, the current discharge continuous until there is insufficient pressure (voltage) to supply the required current, and cranking slows to a stop.

CCA is usually stressed in comparing battery performance, and a higher rated battery will typically give longer cranking time under the same load conditions.

CCA, however is only a very specific characteristic geared to a worst - case starting condition 0 degrees Fahrenheit or -17.8 degrees Celcius). This is not a typical condition.

A battery can be made to meet its CCA rating but fade rapidly at the end of the 30 second test limit. It is also possible to make a battery which meets its CCA rating, but sustains voltage better at more typical starting current and temperatures and has much better Reserve Capacity.

Depending on your driving habits and region, it may be better to select a battery with comparatively high reserve capacity (at the required CCA) rather than simply looking at batteries with higher and higher CCA ratings.

Before attempting to charge a battery, be aware of all the safety precautions you should observe during the charging operation. Always unplug or turn the charger off before attaching, "rocking" or removing the clamp connections. Carefully attach the clamps to the battery in proper polarity (usually red to positive + and black to negative -). Keep open flames and sparks away from the battery, the gases coming from it are highly explosive. Ventilate the battery well during charging. Follow the battery charger manufacturer's instructions .

When possible, use chargers with alternator or polarity protection that prevents charging a battery in reserve. The charge a battery receives is equal to the charge rate in amperes multiplied by the time in hours. Thus a five ampere rate applied to a battery for ten hours would be a 50 ampere - hour (AH) charge to the battery. To fully recharge a battery, you must replace the ampere - hours or ampere minutes removed from it, plus an extra 20 % charge. This is due to the fact that batteries are not 100 % efficient on recharging.

Specific charging rates or times cannot be specified for batteries due to following :

1. The electrical capacity of the battery, the charge required to recharge a fully discharged battery depends on the battery capacity rating. An 80 minute reserve capacity battery requires twice as much recharging as a 40 minutes reserve battery .
2. Temperature of the electrolyte - a partially charged battery will accept the maximum permissible charge rate at 80 Fahrenheit (26.7 Celcius) but will accept only a fraction of this rate at 0 Fahrenheit (-17.8 Celcius). Reference safety Precaution for charging batteries below 32 Fahrenheit (0 Celcius).
3. Battery state of charge at the start, of the charging period - a completely discharged battery requires twice as much charge as a one - half charged battery.
4. Battery age and condition - a battery that has been subjected to severe service will require more charging than a relatively new battery, but the temperature will rise faster. As the temperature rises, the battery charge acceptance increases. Guard against overheating .
5. Caution : do not attempt to charge a frozen battery. Allow the battery to warm to 60 Fahrenheit (15.5 Celcius) before placing on charge .

Batteries should always be treated with caution, whether undercharged or not. All lead - acid batteries contain highly corrosive sulfuric acid and generate explosive gases. Read and follow all warning labels displayed on the battery .

Even so - called "sealed" maintenance - free batteries have small vents to relieve the pressure of internally generated gases and can leak or spew acid if tipped or charged too vigorously .

Although hydrogen and oxygen are always being generated, they are produced in great quantity when the battery is being charged, therefore, several precautions should always be taken :

1. Always charge a battery in an area where the charger and battery are well ventilated and unlikely to be disturbed .
2. Never allow smoking, open flames, or sparks near a battery - undercharged or not .
3. Always switch off and unplug the charger before connecting or disconnecting the battery. Make sure the leads are connected to the proper battery terminals .
4. Never wiggle the connections to check contact while the charger is on or plugged in .
5. Do not allow the battery to overheat (become hot to touch) during recharge
6. Keep the vent pods or plugs in place recharging .
7. Read and understand the charger manufacturer's instruction before attempting to use the equipment .

The charging current and time required depends upon the charger being used and the battery in question. Most chargers automatically adjust to the battery's state of charge and shut off when the battery becomes adequately charged. Many chargers have minimum voltages that must be present in the battery before the charger will switch on. Normally, voltages that must be present in the battery before the charger will switch on. Normally ,these low voltages are well below those exhibited by a battery that appears "dead" to a vehicle's electrical system .

Some chargers have optional settings for six versus twelve volts and / or low maintenance versus standard or deep-cycle batteries. Be sure you have made the proper setting.

If the charger requires manual adjustment for current or shut-off, check the charger's instruction for the settings appropriate to the battery's rating .