BATTERY
The automotive battery, also known as a "lead-acid
storage battery", is an electrochemical device that
produces voltage and delivers current. In an automotive
battery we can reverse the electrochemical action, thereby
recharging the battery, which will then give us many years
of service. The purpose of the battery is to supply current
to the starter motor, provide current to the ignition system
while cranking, supply additional current when the demand
is higher than the alternator can supply, and act as an
electrical reservoir.
The automotive battery requires special handling. The electrolyte
(water) inside the battery is a mixture of sulfuric acid
and water. Sulfuric acid is very corrosive; if it gets on
your skin it should be flushed with water immediately. Likewise,
if it gets in your eyes it should be flushed with a mild
solution of baking soda and water immediately and you should
see a doctor as soon as possible. Sulfuric acid will eat
through clothing, so it is advisable to wear old clothing
when handling batteries. It is also advisable to wear goggles
and gloves while servicing the battery. When charging, the
battery will emit hydrogen gas. It is therefore extremely
important to keep flames and sparks away from the battery.
Because batteries emit hydrogen gas while charging, the
battery case cannot be completely sealed. Years ago there
was a vent cap for each cell and we had to replenish the
cells when the electrolyte evaporated. Today's batteries
(maintenance-free) have small vents on the side of the battery
cover. The gases emitted have to go through baffles to escape.
During this process the liquid condenses and drops back
to the bottom of the battery. Normally there's no need to
replenish or add water to the battery.
Today's batteries are rated in "cold cranking amps".
This represents the current that the battery can produce
for 30 seconds at 0 degrees before the battery voltage drops
below 7.2 volts. An average battery today will have a CCA
(Cold Cranking Amps) of 500. With the many different makes
and models of cars available today, batteries will come
in many different sizes, but all sizes come in many CCAs.
Make sure you get a battery strong enough to operate properly
in your car. The length of the warranty is not indicative
of the strength of the battery.
Battery cables are large diameter, multi-stranded wires
which carry the high current necessary to operate the starter
motor. Some battery cables will have a smaller wire soldered
to the terminal, which is used to either operate a smaller
device or to provide an additional ground.
Even maintenance-free batteries need periodic inspection
and cleaning to insure they stay in good working order.
Inspect the battery to see that it is clean and that it
is held securely in its carrier. Some corrosion may collect
around the battery. Electrolyte condensation contains corrosive
sulfuric acid, which eats away the metal of battery terminals,
cable ends and battery hold-down parts. To clean away the
corrosion, use a mixture of baking soda and water and wash
all the metal parts around the battery. Rinse with water.
Remove the battery cables from the battery (negative cable
first) and wire brush the inside of the cable end and the
battery post. Reinstall the cables (negative end last) and
coat all exposed metal parts (paint or grease can be used).
