| Tweet |
Custom Search
|
|
|
||
 TM 9-8000
capacity ratings according to the ampere-hours
and negative plates and the electrolyte to their original
condition. When all the sulfate on the plates has been
obtained from the battery under certain working
returned to the electrolyte to form sulfuric acid, the cell is
conditions. The capacity of a battery is the number of
recharged fully and ready to be used for the next
amperes delivered, multiplied by the number of hours the
discharge. Charging should be started before both
battery is capable of delivering this current. One of the
plates have become sulfated entirely. The chemical
inherent characteristics of a storage battery is that its
process in the cell during discharge and charge is shown
ampere-hour capacity depends upon the rate of
in figure 12-6.
discharge. A battery will give more ampere-hours at a
b. Electrical Action. A storage battery can be
long, low, or intermittent discharge rate than at a short,
high, or continuous discharge rate. This is because the
charged by direct current only. If only alternating current
voltage drops faster at higher rates. Like other chemical
is available, a motor-generator set or a rectifier must be
processes, the battery is less efficient in cold weather
used to convert it into direct current. In charging, the
than in hot weather. At 0F (-18C), a battery has only
positive wire of the charging circuit must always be
approximately 40 percent of the full cranking capacity
connected to the positive (+) terminal of the battery and
available at 80F (27C). In an emergency, little, if any,
the negative wire to the negative (-) terminal. The
permanent harm will result if the battery is discharged at
electrolyte in each cell must be brought to the proper
a very high rate, provided it is promptly recharged. The
level by the addition of pure water before the battery is
battery is likely to deteriorate if left in a discharged
charged.
condition.
c. Capacity. All batteries are given normal
Section III. TYPES OF BATTERIES
be able to sustain high discharge rates for relatively long
12-6. Deep-Cycle Battery. Deep-cycle batteries are
periods of time. At the same time, they must have a high
units that are designed to be subjected to heavy
specific power output and be relatively lightweight. The
discharge loads for long periods of time. They also must
golf cart battery has thicker plates than the SLI battery
be able to take high-rate charging. The batteries used in
and can withstand about 200 to 400 deep cycles.
forklifts (or any electric vehicles) are nickel cadmium or
lead acid. Because the initial cost of nickel-cadmium
c. Semi-Industrial Battery. The semi-industrial
batteries are approximately 35 times that of lead acid,
battery has thicker plates and is larger and heavier than
they are used only when their cost can be justified in
the golf cart battery. It can withstand about 500 to 1,000
terms of their extremely long cycle life. Lead-acid
deep cycles through its life.
batteries come in four basic varieties:
d. Industrial Battery. The industrial battery is used
a. SLI Battery. The SLI (starting, lighting, and
mainly as a source of power in electric industrial
ignition) battery is designed to deliver high power outputs
vehicles, where cycle life and total power output are
for relatively short periods of time. Because of its thin
important. In some cases industrial batteries will use
plate design, it has less energy available than a deep
tubular plates instead of the standard pasted plates.
cycle battery and will have a life limited to less than 100
This design can withstand as much as 2,000 deep cycles
deep discharge cycles. It is suited to automotive usage
during its life though it exhibits a low power density,
because it is lightweight and has a higher specific power
resulting in a very large, heavy battery.
output (power-per-pound) than deep cycle batteries. In
normal automotive usage, the life of an SLI battery may
12-7. Nickel-Cadmium Batteries.
exceed 5,000 shallow cycles (starting an engine and
recharging would be considered a shallow cycle).
a. General. The nickel-cadmium, alkaline battery
b. Golf Cart Battery. The golf cart battery must
has been receiving serious consideration
12-6
|
||
|
||
