Specifications

amp/hour rating which would give us a maximum recharge rate of forty amps for this

example. The time period of the bulk stage could then be determined from one hundred

and twenty percent of the charge depletion depth divided by the average recharge rate.

This would give a time period of three hours for the bulk stage of the charging process.

The second stage that was observed and studied for charging circuits is known as the

absorption stage. This is characterized by when the charger for the battery keeps a

constant voltage set on the positive and negative terminals of the battery. Slowly as the

internal resistance of the battery begins to grow as it nears full capacitance the current

supplied to the battery is decreased. For the specified battery in this project the constant

voltage at this stage in the recharging process would be between thirteen and fourteen

volts and would be the highest constant voltage in the recharge process would be at its‟

zenith in this stage. At the end of this stage the battery would have been brought from

around ninety percent capacity to one hundred percent capacity. Now that the battery

has been brought to full capacity the remaining two stages would be for maintaining and

reconditioning the battery.

The third stage that was observed and studied for charging circuits is known as the float

stage of the charging process. It is characterized by a very low voltage being supplied to

the battery in order to provide a small but constant maintenance charge in order for the

battery to remain at maximum capacity. Over time the battery has a natural self-

discharge that although small is indeed measurable. To prevent this, a current less than

an amp is supplied to the battery to allow the battery to replenish itself as it slowly self-

discharges. Many batteries do not require a float stage in their charging process

because of an extremely slow self-discharge rate, however it was a variable in choosing

a charging system that was felt deserved due consideration none the less since all

batteries succumb to some type of self-discharge in their lifetime.

The fourth and final stage that was observed and studied for the charging circuits is

known as the equalization stage of the charging process. This stage is characterized by

an attempt by the charger to equalize the voltage in the various cells of a battery. This is

accomplished by applying a voltage slightly higher than the constant voltage measured

in the absorption stage and the placed across each individual cell inside of the battery.

Many chargers implement this as part of their charging cycle as an attempt to prevent a

buildup of minerals such as sulfate on the plates within the battery that would decrease

the life of the battery. Implementing an equalizing state ensures a longer battery life as

well as all cells within a battery being brought up to the same voltage level. This stage is

not as crucial as others, however if a battery is compatible with a equalization process it

is highly recommended to include one in a charging system. The following graph

illustrates as an example how these processes working together have an effect on the

voltages amperages and capacitances within the specified battery in a given scenario.

From this graph the different stages can be differentiated from each other and gives an

idea of what to expect during testing.