Servicing Battery System

Information Sheet 2.1.1: Identify and Explain Safety handling of tools and equipment

The electrolyte of a fully charged battery is usually about 64% water and 36% sulfuric
acid, which corresponds to a specific gravity of 1.270. Specific gravity is the weight of a
given volume of any liquid divided by the weight of an equal volume of water. Pure water
has a specific gravity of 1.000, while battery electrolyte should have a specific gravity of
1.260 to 1.280 at 80OF (26.7OC). In other words, the electrolyte should be 1.260 to 1.280
times heavier than water.

The specific gravity of the electrolyte decreases as the battery discharges. This is why
measuring the specific gravity of the electrolyte with a hydrometer can be a good indicator
of how much charge a battery has lost. Table 17-1 lists specific gravity readings in various
stages of charge with respect to a battery’s ability to crank an engine at a temperature of
80OF (26.7OC).

TABLE 17-1 ELECTROLYTE SPECIFIC GRAVITY AS

RELATED TO CHARGE

Specific Gravity Percent of Charge

1.265 100%

1.225 75%

1.190 50%

1.155 25%

1.120 or lower discharged

CAUTION!

Electrolyte is very corrosive. It can cause severe injuries if it
comes in contact with your skin or eye. If electrolyte gets on you,
immediately wash with baking soda and water. If the acid gets
in your eyes, immediately flush with cool water. Then get
medical help.

Temperature Correction It is necessary to correct the reading by adding or
subtracting 4 points (0.004) for each 10OF (-12OC) above or below the standard of
80OF (26.7OC). Most hydrometers have a built-in thermometer to measure the

temperature of the electrolyte (Figure 10). The hydrometer reading can be misleading

if the hydrometer is not adjusted properly. For example, a reading of 1.260 taken at
20OF (-6.6OC) would be 1.260 – (6× 0.004 or 0.024) = 1.236. This lower reading means

the cell has less charge than indicated.

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Information Sheet 2.1.1: Identify and Explain Safety handling of tools and equipment

Figure 10 Hydrometer with thermometer correction scales make adjusting for electrolyte temperature
easy.

It is important to make these adjustments at high and low temperatures to determine the
battery’s true state of charge

Interpreting Results The specific gravity of the cells of a fully charged battery should near
1.265 when adjusted for electrolyte temperature.

Recharge any battery if the specific gravity drops below an average of 1.230. A specific
gravity difference of more than 50 points between cells is a good indication of a defective
battery in need of replacement.

Built-In Hydrometer
On some sealed maintenance-free batteries, a special temperature-compensated hydrometer
is built into the battery cover (Figure 11). A quick visual check indicates the battery state of
charge (Figure 12). It is important when observing the hydrometer that the battery has a
clean top to see the correct indication. A flashlight may be required in poorly lit areas. Always
look straight down when viewing the hydrometer.

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Information Sheet 2.1.1: Identify and Explain Safety handling of tools and equipment
Figure 11 Sight glass in a maintenance-free battery.

Figure 12 Design and operation of built-in hydrometers on
maintenance-free sealed batteries.

Many maintenance-free batteries do not have a built-in hydrometer. A voltage
check is the only way to check this type of battery’s state of charge. The specific
gravity of these batteries cannot be checked because they are sealed. Never pry off
the cell caps to check the electrolyte levels of condition of a sealed battery.

A few battery designs incorporated a charge indicator into the top of the battery
(Figure 12). Rather than a built-in hydrometer, these batteries use a color display to
note the battery’s state of charge. The color green stands for “OK” gray for “check or
recharge,” and white for “change or replace.”

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Worksheet 2.1.2: Tools/ Equipment and instrument and its Safety Handling
Learning outcomes:
2. Test Automotive Battery
Learning Activity:
2.1 Identifying Tools and Equipment

Select / determine the correct answer given below;
Match Column A to Column B

Battery Strap

Battery Terminal Cleaner

Battery Brush

Lisle Wire Terminal

Battery Handler

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Worksheet 2.1.2: Tools/ Equipment and instrument and its Safety Handling

Multiple Choice: Select the correct answer to the given question

1. The external brush cleans cable clamps and internal brush cleans terminal posts
a. Battery brush
b. Battery strap
c. Battery terminal cleaner
d. Battery handler

2. Sharp steel blades on this tool remove corrosion and put a correct angle on
terminal clamps and post
a. Battery brush
b. Battery strap
c. Battery terminal cleaner
d. Battery handler

3. Is a device which can be used to gather data about electrical circuits
a. Hydrometer
b. Multi-tester
c. Voltmeter
d. ammeter

4. Used to measure a specific gravity of a battery.
a. Hydrometer
b. Multi-tester
c. Voltmeter
d. Ammeter

5. Designed to fit the top of the spline post for easy pulling.
a. Battery strap
b. Battery terminal cleaner
c. Battery puller tool
d. battery

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Worksheet 2.1.2: Tools/ Equipment and instrument and its Safety Handling
ANSWER KEY

Battery Brush
Battery Handler
Lisle Wire Terminal

Battery Strap
Battery Terminal Cleaner

TEST 2. MULTIPLE CHOICE
1. A
2. C
3. B
4. A
5. C

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Operation Sheet 2.1.3 : Use of Battery Hydrometer Tester

Learning outcomes:
2 Testing Automotive Battery
Learning Activity:
2.1 Steps on how to use battery hydrometer tester

How to Use a Battery Hydrometer

Hydrometer Testers:
Figure 1. (Kinds of Hydrometer tester)

Instructions: (Steps on how to use battery tester)

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Operation Sheet 2.1.3 : Use of Battery Hydrometer Tester
1. Remove all the storage battery’s vent caps and set the aside.

2. Squeeze the bulb on the battery hydrometer closed before inserting the pickup
tube in the battery cell nearest the positive battery post. NEVER squeeze the
hydrometer’s bulb with the pickup tube in the battery. The inrush of air will force
the electrolyte out of the battery.

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Operation Sheet 2.1.3 : Use of Battery Hydrometer Tester
3. By releasing the bulb slowly, let enough electrolyte into the hydrometer to make
the float just rise off the bottom and drift freely.

4. Lean over to sight across the liquid to read the specific gravity with out removing
the pickup tube from the cell.

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Operation Sheet 2.1.3 : Use of Battery Hydrometer Tester
5. Record the specific gravity and the temperature of the electrolyte for that cell.

6. Holding the pickup tube just above the electrolyte, slowly release the electrolyte
back in the cell.

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Operation Sheet 2.1.3 : Use of Battery Hydrometer Tester

7. Repeat steps 1 – 6 for all the remaining cells. A 12-volt cell has six cells and a 6-
volt battery has three cells.

Note: (refer table1- below for the specific gravity reading)

Table 1 - Specific Gravity ( Level table)

STATE OF SPECIFIC 12 VOLT 6 VOLT
CHARGE GRAVITY
12.7 6.3
100 1.265
PERCENT 12.4 6.2
75 PERCENT 1.225 12.2 6.1
50 PERCENT 1.190
12.0 6.0
25 PERCENT 1.190 11.9 6.0
DISCHARGED 1.120

Correct the specific gravity reading for the temperature.

Most battery hydrometer has a built-in temperature correction table similar to this one.
To correct for temperature, all you have to do is add or subtract the indicate amount
from the specific reading you obtained for that cell. Compare the corrected reading to
the specific gravity is listed in the State of Charge table to determine the battery’s
state of charge.

Safety Precautions to be observed when testing A Battery

1. Always wear eye protection, safety goggles, or a fill-face shield. Battery electrolyte
is very caustic and can burn your face and even blind you if it gets in your eyes.

2. Always wear mechanic’s gloves to protect your hands.

3. Place a fender cover on the car’s fender to protect the car’s finish from the
electrolyte.

4. Do not smoke when checking a battery. The gasses emitted from a battery are
highly flammable the electrolyte back in the cell.

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Operation Sheet 2.1.4 : Use of Multi-Tester

Learning outcomes:
2 Test Automotive Battery
Learning Activity:
2.1 How to use multi-tester

How to Use a Multi-tester

MEASURING CURRENT, VOLTAGE AND RESISTANCE

1. Turn the zero position adjuster so that the pointer may align right to the zero position.

2. Select a range proper for the item to be measured, set the range selector knob accordingly.
NOTE: When determining a measuring range, select such one for higher voltage than the value to
be measured as well as where the pointer of a meter moves to a considerable extent. However,
select the maximum range and measure in case the extent of value to be measured cannot be
predicted.

MEASURING DCV (Direct Current Voltage)
1. Set the range selector knob to an appropriate DCV range.
2. Apply the black test pin to the minus potential of measured circuit and the red test pin to the plus

potential.
3. Read the move of the pointer to V and A scale.

(Refer to SCALE READINGS figure on page 17)

MEASURING ACV (Alternating Current Voltage)
1. Turn the range selector knob to an appropriate ACV range.
2. Apply the test leads to measured circuit.
3. Read the move of the pointer by V and A scale. (Use AC 10V scale for 10V range only.)

 Since this instrument employs the mean value system for its AC voltage measurement
circuit, AC waveform other than sine wave may cause error.

 There occurs error under such frequencies other than specified in the specification.

MEASURING DCA (Direct Current Amperes)
1. Turn the range selector knob to an appropriate DCA range.
2. Take out measured circuit and apply the black test pin to the minus potential of measured circuit

and the red test pin to the plus potential.
3. Read the move of the pointer by V and A scale.

MEASURING OHMS ()

NOTE: Do not measure resistance in a circuit where a voltage is present.
1. Turn the range selector knob to an appropriate  range.

2. Short the red and black test pins and turn the  adjustment so that the pointer may align exactly to
. (If the pointer fails to swing up to  even when the  adjuster is turned clockwise fully, replace

the internal battery with a fresh one.)
3. Apply the test pin to measured resistance.
4. Read the move of the pointer to  scale.

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Operation Sheet 2.1.4 : Use of Multi-Tester

Note: The polarity of + and - turns reverse to that of the test leads when measurement is done
in  range.

MEASURING CAPACITOR (C)

1. Set the range selector knob to C(F).

2. Measure the capacitance by applying the test pin to the capacitor to be measured after 

adjustment made in the same manner as in the resistance measurement.
3. The pointer moves full scale by the charge current to the capacitor. However, the pointer starts

gradual returning from a certain point. Read the then indicated maximum value on C(F) scale.
Note: Be sure to short circuit both ends of the capacitor for discharge prior to the initial measure
after the measurement was once made.
Pay due attention to the polarity (+ and -) of the capacitor. (Connect + side of the capacitor to -
side of the tester.)

MEASURING AF OUTPUT (dB)

1. dB (decibel) is measured in the same way as ACV measurement reading the dB scale instead.
For measurement on the 10V range, the dB scale (-10dB - +22dB) is read directly, but when
measured on the 50V range, 14dB is added. On the 250V range, 28dB is added.
Thus, the maximum dB readable is 22 + 40 = 62(dB) measured on the 1000V range.
Note: Cut direct current with a capacitor of 0.1F or more when measuring such signal as
having direct current.

MEASURING OF ICEO (Leak Current) FOR TRANSISTOR from
black
1. Adjust 0 by setting the range selector knob to a proper range
X1~X1k.

2. For NPN transistor, apply a black test pin to the collector and the
one to the emmiter.

3. Determine the leak current by ICEO scale indicated on the scale
plate. (Unit in A, mA)

MEASURING OF DIODE (Including LED)

1. Adjust 0 by setting the range selector knob to a to
proper range from X1 (150mA)~ X100k (1.5A). one

2. Apply the black test pin to anode side and the red one for
cathode side when measuring IF (forward current).
Apply the black test pin to cathode side and the red
to anode side when measuring IR (reverse current).

3. Read the indicated value by LI scale. (The pointer
moves to a considerable extent for IF, and little extent
IR)

4. Value indicated on LV scale during the measurement is the forward voltage of diode.

Note: Additional information is available in the supplemented Learning Element entitled "Measuring
Electrical Voltage Using a Multimeter".

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Operation Sheet 2.1.4 : Use of Multi-Tester
SCALE READINGS

Range Multiplied Range Multiplied
X 100K DCV 10 X1
 X 100K X1k 4 DCV 1000 X100
X10 ACV 1000 X100
1 X1k X1 5 ACV 10 X1
X10 X1 6 C (F) X1
X0.01 150mA at X1 X10 (mA)
X1 X0.001 15mA at X10 X1 (mA)
X1 7 15A at X1k X10 (A)
DCV 250 X0.001 1.5A at X100k X0.1 (A)
X0.1 8 LV X1
DCV 2.5 X0.01 9 hFE X1
X1 ACV 10 X1
DCV 0.25 X1 ACV 50 14dB added
X1 10 ACV 250 28dB added
2 ACV 250 X0.01 40dB added
ACV 1000
DCA 0.25

DCA 25m

DCA 2.5m

DCV 50

3 ACV 50

DCA 50

4 DCV 0.1

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
ALT7233103 Sept. 20, 2010 3

Information Sheet 3.1.1: Automotive Battery Testing

Learning outcomes:
3 Testing Automotive Battery

Learning Activity:
3.1 Testing Automotive Battery

BATTERY TESTING

Battery testing has changed in recent years; although the three areas are basically the same,
the equipment has improved.

1. Visual Inspection

2. State of Charge

a. Specific Gravity
b. Open Circuit Voltage

3. Capacity or Heavy Load Test

VISUAL INSPECTION (see Figure 1)

Battery service should begin with a thorough visual inspection. This inspection may reveal
simple, easily corrected problems.

1 . Check for cracks in the battery case and broken terminals. Either may allow electrolyte
leakage, which requires battery replacement.

2. Check for cracked or broken cables or connections. Replace, as needed.

3. Check for corrosion on terminals and dirt or acid on the case top. Clean the terminals and
case top with a mixture of water and baking soda. A battery wire brush tool is needed for
heavy corrosion on the terminals.

4. Check for a loose battery hold-down or loose cable connections. Clean and tighten, as
needed.

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Information Sheet 3.1.1: Automotive Battery Testing

Fig.1 Visual Inspection

5. Check the electrolyte fluid level. The level can be viewed through the translucent
plastic case or by removing the vent caps and looking directly into each cell. The proper
level is 1/2" above the separators (about 1/8" below the fill ring shown below). Add
distilled water if necessary. Do not overfill.

6. Check for cloudy or discolored electrolyte caused by overcharging or vibration. This
could cause high self discharge. Correct the cause and replace the battery.
(see figure 2 below.)

Fig.2 Electrolyte fluid level

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Information Sheet 3.1.1: Automotive Battery Testing

STATE OF CHARGE

The state of charge of a battery can be easily check in one of two ways:

1) Specific Gravity Test

2) Open Circuit Voltage Test

Note 1: A state of charge test is required to determine if there is sufficient charge in the battery
to properly perform a capacity test (explained later).

Note 2: The only exception to this is the MIDTRONICS Battery Tester. This new state of the
art capacitance tester will be discussed later in this module.

SPECIFIC GRAVITY

Specific gravity means exact weight. A "Hydrometer" or a "Refractometer" compares the exact
weight of electrolyte with that of water. Strong electrolyte in a charged battery is heavier than
weak electrolyte in a discharged battery. By weight, the electrolyte in a fully charged battery is
about 36% acid and 64% water. The specific gravity of water is 1.000. The acid is 1.835 times
heavier than water, so its specific gravity is 1.835. The electrolyte mixture of water and acid
has a specific gravity of 1.270, usually stated as "twelve and seventy." (see Figure 3 below)

Fig.3 Composition of Electrolyte

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Information Sheet 3.1.1: Automotive Battery Testing

SPECIFIC GRAVITY READINGS

By measuring the specific gravity of the electrolyte, you can tell if the battery is fully
charged, requires charging, or must be replaced. It can tell you if the battery is
sufficiently charged for a capacity (heavy-load) test. The battery must be at least 75%
charged to perform a heavy load test. (The heavy load test will be discussed later). In
other words, each cell must have a specific gravity of 1.230 or higher to proceed. (see
Table Below).

CELL READINGS PERCENT CHARGED
1.270 100 %
1.230 75%
1.190 50%
1.145 25%
1.100 0%

Table 1.

If the battery is less than 75% charged, it must be fully recharged before proceeding. If
the battery is 75% or higher proceed to a heavy load test. A battery not sufficiently
charged will fail because it is discharged.

SPECIFIC GRAVITY - EXCESSIVE CELL VARIATION READINGS

Variation in specific gravity among cells cannot vary more than 0.050. The variance is
the difference between the lowest cell and the highest cell. A battery must be
condemned for excessive cell variation if more that 0.050. In the example below, the
highest SG reading is cell #1 (shown in green) while the lowest SG reading is cell #5
(shown in blue); the difference is 0.070 which requires battery replacement. Cell #5 if
failing. (see Table 2. below)

Cell #1 Cell #2 Cell #3 Cell #4 Cell #5 Cell #6
1.260 1.230 1.240 1.220 1.190 1.250

Table 2.

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Information Sheet 3.1.1: Automotive Battery Testing

Many factors contribute to cell variation; for example, if water was just added to that cell, the
cell is then diluted with water resulting is a lower specific gravity reading. Recharging the
battery would correct this false reading. In some cases if a battery that has cell variation
slightly over the specification and is only about 50% charge, charging the battery at a slow rate
of charge (5A) may reduce the cell variation, thus saving the battery.

ADJUSTED SPECIFIC GRAVITY READINGS

Temperature correction is needed because specific gravity changes with temperature. Cold
thickens the electrolyte and raises the specific gravity. Heat thins the electrolyte and lowers the
specific gravity. Hydrometers are calibrated at 80'F (26.7'C). Electrolyte temperatures above or
below 80'F must be adjusted. For every 10'F increment below 80'F, subtract 0.004 to the
hydrometer readings, and for each 10'F increment above 80'F, add 0.004 to the readings. See
the examples figure below.

Fig.4 Sample of Specific Gravity Reading
OPEN CIRCUIT VOLTAGE

A digital voltmeter must be used to check the battery's open-circuit voltage. Analog meters
are not accurate and cannot be used.

1 . Turn on the headlamps' high beam for several minutes to remove any surface charge.

2. Turn headlamps off, and connect the digital voltmeter across the battery terminals.

3. Read the voltmeter. A fully charged battery will have an open-circuit voltage of 12.6
volts. On the other hand, a totally dead battery will have an open-circuit voltage of less
than 12.0 volts.

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Information Sheet 3.1.1: Automotive Battery Testing

Note: If the battery is 12.4v or higher, proceed to heavy load test. If the battery is less
than 12.4v, the battery must be fully recharged before testing. Be sure to remove the
surface charge completely; this is the number one mistake technicians make. If need
be, place a load tester on the battery and load the battery for 10 seconds at
approximately 200 amps. Allow a few minutes for the battery to recover then measure
the open circuit voltage. This should remove the surface charge and allow an accurate
open circuit voltage measurement. (Remember: a reading of 12.4 volts or higher load
test the battery, 12.3 volts or less, recharge the battery.) See figure below.

% of charge
12.6v = 100%
12.4v = 75%
12.2v = 50%
12.0v = 25%
11.9v = 0%

Fig.5 Open Circuit Voltage

HEAVY LOAD TEST

While a State of Charge test determines the battery's state of charge, it does not
measure the battery's ability to deliver adequate cranking power. A capacity or heavy-
load test measures the battery's ability to deliver current. A battery load tester such as a
Sun VAT-40 is used. (Note: the battery must be at least 75% charged before a heavy
test can be performed.). See figure below.

Fig.6 Conduct Heavy-Load Test

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Information Sheet 3.1.1: Automotive Battery Testing

DETERMINE CAPACITY RATING

The capacity rating is located on the battery label. Ratings can be expressed in CCA (Cold
Cranking Amps), AH (Amp-Hour), or JIS (Japanese Industrial Standard.) JIS uses a six digit
code (not shown). A conversion table is offered below that can be printed. If no rating is found
on the battery, then use the OEM battery rating found in most repair manuals.

CURRENT DRAINS

Parasitic drains are the small current drains required to operate various electrical systems,

such as the clock, computer memory, or alarms that continue to work when the car is parked

and the ignition is off. All vehicles today have parasitic drains and over time will drain all

batteries if not driven or charged periodically. The problem is when the parasitic drain

becomes excessive, usually over 35 milliamps.

Unwanted battery drain can also be the reason why a battery keeps discharging. Unwanted
battery drain can be a result of excessive parasitic drain, or if the top of the battery is wet or
has excessive corrosion, it could create a path between the two battery posts, causing a
current drain; usually 0.5 volt potential or higher will result in a battery discharge. This is
called Case Drain.

Fig.7 Current Drains

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Information Sheet 3.1.1: Automotive Battery Testing

PARASITIC DRAIN
Check for excessive battery drain or parasitic loads using an ammeter. Make sure all
electrical loads are off in the car, doors closed, and the key is out of the ignition
switch . Disconnect one of the battery cables from the battery, placing an ammeter in
series between the battery post and cable clamp. The current draw reading should
be less than 35 milliamps. A reading higher than this (or manufacturer specifications)
would indicate excessive battery drain. Something is "on", allowing current to flow
running down the battery. Vehicles today typically will draw less than .020 amps (20
milliamps) of current to maintain electronic memories and circuits.

Fig.8 Parasitic Drain

Note: If the battery is disconnected parasitic drains may temporarily increase.
Circuits in the engine and body computers are activated and will run until internal
timers runout. This reactivation period could be anywhere from a few seconds to
almost 30 minutes. Whenever possible avoid disconnecting the battery while
performing this test. It is possible to place one lead of the ammeter on the battery
post and the other on the battery clamp, while at the same time lifting the battery
clamp off the battery post. On side terminal batteries, connect the voltmeter with
alligator clips and let sit until the timers run out.

BATTERY DISCHARGE / CASE DRAIN

Check for battery discharge (case drain) across the top of the battery using a digital
voltmeter. Connect the negative (black) test lead to the battery's negative terminal post, and
connect the positive (red) test lead to the top of the battery case. If the meter reads more
than 0.5 volt, clean the case topusing a solution of baking soda
and water Remove excess water from top of battery. (see Figure 9.)

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Information Sheet 3.1.1: Automotive Battery Testing

Fig. 9 Battery Discharge Connection

BATTERY CLAMP - POST RESISTANCE

Resistance between the battery terminal post and the clamp can account for the battery
not being completely recharged and is often a problem. Although it may visually look all
right, oxidation of the metal or slight corrosion can cause excessive resistance at the
connection, thus creating a voltage drop and lowering current flow to the starter. Battery
post and clamps should be cleaned at each battery inspection. To check for excessive
resistance, perform a voltage drop between the battery terminal post and the clamp
(shown below) while cranking the engine. The voltage drop reading should be 0.0 volts.
Any voltmeter reading higher than "zero" volts requires cleaning the connection and
rechecking. See figure below.

Fig. 10 Battery Post Resistance using Multi Tester

Code No. Servicing Automotive Battery Date: Developed Date: Page #
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Worksheet 3.1.2. : Automotive Battery Testing

Learning outcomes:
3. Test Automotive Battery
Learning Activity:
3.2 Test on Testing Automotive Battery

Select / determine the correct answer given below:

1. A mixture of water and sulfuric acid?
a. Battery
b. Hydrometer
c. Electrolyte
d. Sponge lead

2. Percentage of electrolyte?
a. 65% acid and 35% water
b. 70% water and 30% acid
c. 35% acid and 65% water
d. 30% acid and 70%water

3. If the battery cell reading is 1.270 specific gravity. What is the percentage charged?
a. 75%
b. 25%
c. 100%
d. 65%

4. Used to measure the specific gravity/
a. Multi-meter
b. Ohm-meter
c. Gravity meter
d. Hydrometer

5. _________ used to measure the battery open-circuit voltage.
a. Voltmeter
b. Current meter
c. Hydrometer
d. Multi-meter

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
ALT723303
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Worksheet 3.1.2. : Automotive Battery Testing

ANSWER KEY

1. C
2. C
3. C
4. D
5. A

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Sept. 19,2010 2

Job Sheet 3.1.3a: Battery Testing Procedure (using Hydrometer Tester)

Learning outcomes:
3 Test Automotive Battery
Learning Activity:
3.1 Determine/Perform procedure in testing/checking electrolytic level of automotive battery

.

Steps in checking electrolytic level of automotive battery using Hydrometer:

Figure: Test / Check electrolytic level of automotive battery

SPECIFIC GRAVITY TEST PROCEDURE (HYDROMETER)

 1. Wear suitable eye protection.
 2. Remove vent caps or covers from the battery cells.
 3. Squeeze the hydrometer bulb and insert the pickup tube into the cell closest to

the battery's positive (+) terminal.
 4. Slowly release the bulb to draw in only enough electrolyte to cause the float to

rise. Do not remove the tube from the cell.
 5. Read the specific gravity indicated on the float. Be sure the float is drifting free,

not in contact with the sides of top of the barrel. Bend down to read the hydrometer
at eye level. Disregard the slight curvature of liquid on the float.
 6. Record your readings and repeat the procedure for the remaining cells.

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Sept. 19,2010 1

Job Sheet 3.1.3a: Battery Testing Procedure (using Hydrometer Tester)

Note: Hydrometer Measurements

When you measure the specific gravity (weight) of each cell, they must all
be within 50% of each other

1.28 Cell 1
1.26 Cell 2
1.24 Cell 3
1.22 Cell 4
Cell 5
1.2 Cell 6
1.18
1.16
1.14
1.12

1.1
1.08

Level

Given the above measurements, write down the specific gravity for each cell on
the table below and put your recommendation;

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Job Sheet 3.1.3a: Battery Testing Procedure (using Hydrometer Tester)

No. of cells Scale Reading Dead Recharge Good
CELL 1
CELL 2
CELL 3
CELL 4
CELL 5
CELL 6

Average

Note: Specific gravity for each cell should be at least 50% for each other:
Overall recommendations: ___________________________________

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Job Sheet 3.1.4b: Battery Testing Procedure (Using Volt Meter)
Learning outcomes:
3 Test Automotive Battery
Learning Activity:
3.1. Determine/Perform Heavy Load Test of automotive battery.

HEAVY LOAD TEST PROCEDURE
1. Install the load tester as shown in an earlier slide.
2. Load the battery by turning the Load Increase control until the ammeter reads 3 times the
amp-hour (AH) rating or one-half the cold-cranking ampere (CCA) rating.
3. Maintain the load for no more than 15 seconds, and note the voltmeter reading.
4. If the voltmeter reading during the test is (see Figure 1.)

Figure 1.

9.6 volts or higher, the battery is good.
9.5 volts or below, the battery is defective and needs
replacement.

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Job Sheet 3.1.4b: Battery Testing Procedure (Using Volt Meter)

Note: Results will vary with temperature. Low temperatures will reduce the voltage reading, so
the electrolyte should be at 70'F or above. If not, use the following conversion table:

Voltage Temperature
9.6 70'F or above
9.5
9.4 60'F
9.3 50'F
9.1 40'F
8.9 30'F
8.7 20'F
8.5 10'F
0'F

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Information Sheet 4.1.1: Removing Automotive Battery

Learning outcomes:
4 Remove Automotive Battery

Learning Activity:
4.1 Removing Automotive Battery

Remove The Negative Cable First,

Re-connect The Negative Cable Last:

Why? Because the wrench or socket is touching the live part of the electrical connector. There
is a good chance that the wrench or socket handle will accidentally touch something.
The entire car is connected to the negative terminal.

If your wrench is on the positive terminal and it accidentally touches anything metal, you
will short circuit the battery. The voltage isn't harmful, but the sudden unexpected sparks will
startle the $hit out of you, and could even burn you. There is so much current (amperage)
available that your wrench literally becomes an arc welder.

If you disconnect the negative cable first, and reconnect it last, then the car is not
electrically connected to the negative battery terminal. After that you can disconnect the
positive battery terminal with minimal risk, because if your wrench touches any metal parts of
the car there is no complete circuit, and nothing happens. The only risk comes from touching
the other (i.e. negative) battery terminal.

While connecting or disconnecting the negative cable, you don't need to worry about the
wrench touching metal parts of the car, because everything is at the same electrical potential.
You only need to keep the wrench from touching the positive battery terminal. That's easy.

Disconnecting A Battery With
Side Terminals:

1. Side-terminal batteries, common on
General Motors products, require a small
socket or wrench to remove the battery
cables.

This used a 5/16" socket.

Code No. Servicing Automotive Battery Date: Developed Date: Page #
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Information Sheet 4.1.1: Removing Automotive Battery
Next: disconnecting the positive battery cable.
2. If that wrench touches something metal,
there will be no short circuit

Wire Colors:
The positive battery cable may be red, and the negative cable is normally black.
Don't judge by the cables... look at the markings on the battery. Many cars with black cables
connected to the positive terminal. The automaker used black-insulated wire to identify the
cables.
Red colored cables are used on the positive terminal of the battery.
The industry standard for automotive wiring is Black = Ground (which is negative), and Red =
Hot (which is positive).
This can be confusing when compared with wire used in buildings, where black (and other
colors) are hot, and white is neutral, which has the same potential as ground.

Code No. Servicing Automotive Battery Date: Developed Date: Page #
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Information Sheet 4.1.1: Removing Automotive Battery

Disconnecting A Battery With
Top Terminals:

1. This battery was installed less than two
years ago, it's already covered in dirt.
Dirt on the surface of a car battery can create
a pathway for a tiny amount of electricity to
flow between the terminals. Eventually this
minor current flow can cause the battery to
become drained down

2. To prevent the radio from losing its preset
stations, try using this 12 volt portable power
supply to keep power supplied to the car
while the battery is removed.
I connected the black alligator clip to the
engine, and the red clip to the positive battery
cable.

3. Loosen the negative battery clamp with a
1/2" wrench.
Most domestic cars require a 1/2" wrench for
the battery terminal clamps.

Code No. Servicing Automotive Battery Date: Developed Date: Page #
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Information Sheet 4.1.1: Removing Automotive Battery
4. Often the battery cable won't come
off. DON'T twist the clamp, you might damage
the battery terminal.
Use a pair of prybars to pry open the soft lead
battery cable end...

Like this…..

A Better Way:
1. This is a battery terminal puller.

Code No. Servicing Automotive Battery Date: Developed Date: Page #
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Information Sheet 4.1.1: Removing Automotive Battery
2. The arms (arrow) go underneath the cable
end clamp, and the center pushes against the
terminal post on the battery.
Turn the handle and the cable end clamp lifts
right up.

3. Then the battery cable can be pulled away.
Be careful... since the cable is so thick it often
tries to spring back to its former position. I've
had a battery cable spring back and touch the
battery terminal. I make an effort to tuck the
cable away.

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Information Sheet 4.1.1: Removing Automotive Battery

Terminal Maintenance:

It's a good idea to clean the battery cable ends and terminals with a wire brush. The terminals
and cable ends are made from lead, which corrodes readily. Corrosion can increase the
resistance of the electrical connection, which can prevent the battery from charging properly.
Corroded battery connectors can create so much voltage drop that the car's starter motor
cranks slowly or not at all.

1. This is a battery terminal brush,

2. Under the cap there is (or was) a
round brush to clean the inside
surface of the cable end clamp.

Even though this is mangled, it still
works okay.

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Information Sheet 4.1.1: Removing Automotive Battery
3. The bottom part have a circular wire brush.

4. I pushed the tool over the battery terminal
while turning it.
This takes about half a minute.

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Information Sheet 4.1.1: Removing Automotive Battery

5. Battery Terminals
Get Corroded:

<-- Left - Before
cleaning with battery
brush.

Right -->
After cleaning with the

battery brush

Removing The Battery:

1. Once the cables had been disconnected,
take the battery out.
But first remove the battery hold-down
bracket. There are two very long bolts (red
arrow) that secure the bracket to the body of
the vehicle.
This vehicle require an 11mm socket to
remove the hold-down bolts.

Code No. Servicing Automotive Battery Date: Developed Date: Page #
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Information Sheet 4.1.1: Removing Automotive Battery
2. Then remove the clamping bracket.

3. Lift out the battery with the built-in strap.
Otherwise this is a two-handed job.
Car batteries are heavy! This thing must
weigh about 40 pounds.

Code No. Servicing Automotive Battery Date: Developed Date: Page #
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Worksheet 4.1.2: Removing Automotive Battery

Learning outcomes:
4. Remove Automotive Battery
Learning Activity:
4.1 : Test on Removing Automotive Battery

Select / determine the correct answer given below:

1. The color code of positive terminal of battery is
a. Blue
b. White
c. Red
d. black

2. In removing battery terminal clip, what terminal should you remove first? Why?
a. Positive terminal because it produces current
b. Negative because the entire car is connected to negative terminal
c. Both a& b
d. Neither a & b

3. The color code of negative terminal of battery is
a. Red
b. Blue
c. White
d. Black

4. A tool used to pry battery cable end
a. Extension bars
b. Ballpen hammer
c. Prybar
d. Screw driver

5. Used to clean battery terminal post
a. Brush
b. Battery terminal brush
c. Battery hold down
d. Steel brush

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Worksheet 4.1.2: Removing Automotive Battery

ANSWER KEY

1. C
2. B
3. D
4. C
5. B

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Job Sheet 4.1.3: Removing Automotive Battery Procedure

Learning outcomes:
4 Remove Automotive Battery
Learning Activity:
4.1 Procedure in Removing Automotive Battery .

Here are the procedure:

1. With the engine off, pop the hood and find
the battery. Detach the negative (black)
battery cable from the battery. First loosen
the nut with a combination wrench. A
better tool to use would be battery pliers or
a battery wrench.

2. Twist and pull up on the end of the cable
with your hand. If it does not come off
easily you may want to purchase a battery
terminal puller from your local auto parts
store. This will help prevent damage to
your battery or cables. It is not
recommended to use a screwdriver as a
pry-bar, this could break off your battery
terminal or cause other damage.

3. Detach the positive (red) battery cable
from the battery using the same method.

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Job Sheet 4.1.3: Removing Automotive Battery Procedure

4. Using a combination wrench or a socket
and ratchet, remove the battery hold-down
clamp.

5. Take the battery out of the battery tray.
Batteries are heavy, so grab from the
bottom using both hands. If the battery has
a handle, use that instead.

6. Use baking soda mixed with water and a
wire brush to clean any corrosion from the
battery tray and the hold-down clamp.

7. Clean the battery cable connectors with a
wire brush. To remove heavy corrosion
from the connectors, use battery-cleaning
solution (available at any auto-parts store).

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Job Sheet 4.1.3: Removing Automotive Battery Procedure

8. Place the new battery in the battery hold-
down tray and secure the battery with the
hold-down clamp. Spray both terminal
ends with anti-corrosion solution (optional).
Attach and tighten the positive battery
cable. Attach and tighten the negative
battery cable. Check that all cable
connectors are tight. If you can move them
at all, your car may not start.

Tips & Warnings
 Battery acid is extremely corrosive. Don't let it splash out. Take care not to spill any on your

hands, body or clothing, or on car paint.
 The old battery cannot go into the regular trash. Take it to a facility that accepts hazardous

material for recycling. You can also return the used battery to the auto-parts store where
you bought the new one.
 Make sure you're connecting the wires to the right battery terminal otherwise you can cause
damage to your vehicle.

Code No. Servicing Automotive Battery Date: Developed Date: Revised Page #
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Information Sheet 5.1.1: Electrical safety in Charging Automotive Battery

Learning outcomes:
5 Charge Automotive battery

Learning Activity:
5.1 Apply Electrical safety in Charging Automotive Battery

Battery Chargers and Charging Methods
Charging Schemes

The charger has three key functions

Getting the charge into the battery (Charging)
Optimizing the charging rate (Stabilizing)
Knowing when to stop (Terminating)

The charging scheme is a combination of the charging and termination methods.

Charge Termination

Once a battery is fully charged, the charging current has to be dissipated somehow. The
result is the generation of heat and gasses both of which are bad for batteries. The essence of
good charging is to be able to detect when the reconstitution of the active chemicals is
complete and to stop the charging process before any damage is done while at all times
maintaining the cell temperature within its safe limits. Detecting this cut off point and
terminating the charge is critical in preserving battery life. In the simplest of chargers this is
when a predetermined upper voltage limit, often called the termination voltage has been
reached. This is particularly important with fast chargers where the danger of overcharging is
greater.

Safe Charging

If for any reason there is a risk of over charging the battery, either from errors in determining
the cut off point or from abuse this will normally be accompanied by a rise in temperature.
Internal fault conditions within the battery or high ambient temperatures can also take a
battery beyond its safe operating temperature limits. Elevated temperatures hasten the death
of batteries and monitoring the cell temperature is a good way of detecting signs of trouble
from a variety of causes. The temperature signal, or a resettable fuse, can be used to turn off
or disconnect the charger when danger signs appear to avoid damaging the battery. This
simple additional safety precaution is particularly important for high power batteries where the
consequences of failure can be both serious and expensive.

Charging Times

During fast charging it is possible to pump electrical energy into the battery faster than the
chemical process can react to it, with damaging results.

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Information Sheet 5.1.1: Electrical safety in Charging Automotive Battery

The chemical action can not take place instantaneously and there will be a reaction gradient
in the bulk of the electrolyte between the electrodes with the electrolyte nearest to the
electrodes being converted or "charged" before the electrolyte further away. This is
particularly noticeable in high capacity cells which contain a large volume of electrolyte.

Fig.1 Cell chemical conversions

There are in fact at least three key processes involved in the cell chemical conversions.

 One is the "charge transfer", which is the actual chemical reaction taking place at the
interface of the electrode with the electrolyte and this proceeds relatively quickly.

 The second is the "mass transport" or "diffusion" process in which the materials
transformed in the charge transfer process are moved on from the electrode surface,
making way for further materials to reach the electrode to take part in the transformation
process. This is a relatively slow process which continues until all the materials have been
transformed.

 The charging process may also be subject to other significant effects whose reaction time
should also be taken into account such as the "intercalation process" by which Lithium
cells are charged in which Lithium ions are inserted into the crystal lattice of the host
electrode.

All of these processes are also temperature dependent.

In addition there may be other parasitic or side effects such as passivation of the electrodes,
crystal formation and gas build up, which all affect charging times and efficiencies, but these
may be relatively minor or infrequent, or may occur only during conditions of abuse. They are
therefore not considered here.

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Information Sheet 5.1.1: Electrical safety in Charging Automotive Battery

The battery charging process thus has at least three characteristic time constants associated
with achieving complete conversion of the active chemicals which depend on both the
chemicals employed and on the cell construction. The time constant associated with the
charge transfer could be one minute or less, whereas the mass transport time constant can be
as high as several hours or more in a large high capacity cell. This is one of the the reasons
why cells can deliver or accept very high pulse currents, but much lower continuous
currents.(Another major factor is the heat dissipation involved). These phenomena are non
linear and apply to the discharging process as well as to charging. There is thus a limit to the
charge acceptance rate of the cell. Continuing to pump energy into the cell faster than the
chemicals can react to the charge can cause local overcharge conditions including
polarization, overheating as well as unwanted chemical reactions, near to the electrodes thus
damaging the cell. Fast charging forces up the rate of chemical reaction in the cell (as does
fast discharging) and it may be necessary to allow "rest periods" during the charging process
for the chemical actions to propagate throughout the bulk of the chemical mass in the cell and
to stabilize at progressive levels of charge.

A memorable though not quite equivalent phenomenon is the pouring of beer into a glass.
Pouring very quickly results in a lot of froth and a small amount of beer at the bottom of the
glass. Pouring slowly down the side of the glass or alternatively letting the beer settle till the
froth disperses and then topping up allows the glass to be filled completely.

Hysteresis

The time constants and the phenomena mentioned above thus give rise to hysteresis in the
battery. During charging the chemical reaction lags behind the application of the charging
voltage and similarly, when a load is applied to the battery to discharge it, there is a delay
before the full current can be delivered through the load. As with magnetic hysteresis, energy
is lost during the charge discharge cycle due to the chemical hysteresis effect.

The diagram below shows the hysteresis effect in a Lithium battery.

Fig.2 Effect of Lithium Battery

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Information Sheet 5.1.1: Electrical safety in Charging Automotive Battery

Allowing short settling or rest periods during the charge discharge processes to accommodate
the chemical reaction times will tend to reduce but not eliminate the voltage difference due to
hysteresis.

Fast charging also causes increased Joule heating of the cell because of the higher currents
involved and the higher temperature in turn causes an increase in the rate of the chemical
conversion processes.

Charge Efficiency

This refers to the properties of the battery itself and does not depend on the charger. It is the
ratio (expressed as a percentage) between the energy removed from a battery during
discharge compared with the energy used during charging to restore the original capacity.
Also called the Coulombic Efficiency or Charge Acceptance.

Charge acceptance and charge time are considerably influenced by temperature as noted
above. Lower temperature increases charge time and reduces charge acceptance.

Note that at low temperatures the battery will not necessarily receive a full charge even
though the terminal voltage may indicate full charge. See Factors Influencing State of Charge.

Basic Charging Methods

 Constant Voltage A constant voltage charger is basically a DC power supply which in its
simplest form may consist of a step down transformer from the mains with a rectifier to
provide the DC voltage to charge the battery. Such simple designs are often found in
cheap car battery chargers. The lead-acid cells used for cars and backup power systems
typically use constant voltage chargers. In addition, lithium-ion cells often use constant
voltage systems, although these usually are more complex with added circuitry to protect
both the batteries and the user safety.

 Constant Current Constant current chargers vary the voltage they apply to the battery to
maintain a constant current flow, switching off when the voltage reaches the level of a full
charge. This design is usually used for nickel-cadmium and nickel-metal hydride cells or
batteries.

 Taper Current This is charging from a crude unregulated constant voltage source. It is not
a controlled charge as in V Taper above. The current diminishes as the cell voltage (back
emf) builds up. There is a serious danger of damaging the cells through overcharging. To
avoid this the charging rate and duration should be limited. Suitable for SLA batteries only.

 Pulsed charge Pulsed chargers feed the charge current to the battery in pulses. The
charging rate (based on the average current) can be precisely controlled by varying the
width of the pulses, typically about one second. During the charging process, short rest
periods of 20 to 30 milliseconds, between pulses allow the chemical actions in the battery
to stabilize by equalizing the reaction throughout the bulk of the electrode before
recommencing the charge. This enables the chemical reaction to keep pace with the rate
of inputting the electrical energy. It is also claimed that this method can reduce unwanted
chemical reactions at the electrode surface such as gas formation, crystal growth and

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Information Sheet 5.1.1: Electrical safety in Charging Automotive Battery

passivation. (See also Pulsed Charger below). If required, it is also possible to sample the
open circuit voltage of the battery during the rest period.

Fig.3 Pulsed Charger

The optimum current profile depends on the cell chemistry and construction.

 Burp charging Also called Reflex or Negative Pulse Charging Used in conjunction with
pulse charging, it applies a very short discharge pulse, typically 2 to 3 times the charging
current for 5 milliseconds, during the charging rest period to depolarize the cell. These
pulses dislodge any gas bubbles which have built up on the electrodes during fast
charging, speeding up the stabilization process and hence the overall charging process.
The release and diffusion of the gas bubbles is known as "burping". Controversial claims
have been made for the improvements in both the charge rate and the battery lifetime as
well as for the removal of dendrites made possible by this technique. The least that can be
said is that "it does not damage the battery".

 IUI Charging This is a recently developed charging profile used for fast charging standard
flooded lead acid batteries from particular manufacturers. It is not suitable for all lead acid
batteries. Initially the battery is charged at a constant (I) rate until the cell voltage reaches
a preset value - normally a voltage near to that at which gassing occurs. This first part of
the charging cycle is known as the bulk charge phase. When the preset voltage has been
reached, the charger switches into the constant voltage (U) phase and the current drawn
by the battery will gradually drop until it reaches another preset level. This second part of
the cycle completes the normal charging of the battery at a slowly diminishing rate. Finally
the charger switches again into the constant current mode (I) and the voltage continues to
rise up to a new higher preset limit when the charger is switched off. This last phase is
used to equalize the charge on the individual cells in the battery to maximize battery life.

 Trickle charge Trickle charging is designed to compensate for the self discharge of the
battery. Continuous charge. Long term constant current charging for standby use. The
charge rate varies according to the frequency of discharge. Not suitable for some battery
chemistries, e.g. NiMH and Lithium, which are susceptible to damage from overcharging.
In some applications the charger is designed to switch to trickle charging when the battery
is fully charged.

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Information Sheet 5.1.1: Electrical safety in Charging Automotive Battery

o Float charge. The battery and the load are permanently connected in parallel across the
DC charging source and held at a constant voltage below the battery's upper voltage limit.
Used for emergency power back up systems. Mainly used with lead acid batteries.

o Random charging All of the above applications involve controlled charge of the battery,
however there are many applications where the energy to charge the battery is only
available, or is delivered, in some random, uncontrolled way. This applies to automotive
applications where the energy depends on the engine speed which is continuously
changing. The problem is more acute in EV and HEV applications which use regenerative
braking since this generates large power spikes during braking which the battery must
absorb. More benign applications are in solar panel installations which can only be
charged when the sun is shining. These all require special techniques to limit the charging
current or voltage to levels which the battery can tolerate.

Charging Rates

Batteries can be charged at different rates depending on the requirement. Typical rates
are shown below:

 Slow Charge = Overnight or 14-16 hours charging at 0.1C rate
 Quick Charge = 3 to 6 Hours charging at 0.3C rate
 Fast Charge = Less than 1 hour charging at 1.0C rate

Slow charging

Slow charging can be carried out in relatively simple chargers and should not result in the
battery overheating. When charging is complete batteries should be removed from the
charger.

 Nicads are generally the most robust type with respect to overcharging and can be left
on trickle charge for very long periods since their recombination process tends to keep
the voltage down to a safe level. The constant recombination keeps internal cell
pressure high, so the seals gradually leak. It also keeps the cell temperature above
ambient, and higher temperatures shorten life. So life is still better if you take it off the
charger.

 Lead acid batteries are slightly less robust but can tolerate a short duration trickle
charge. Flooded batteries tend to use up their water, and SLAs tend to die early from
grid corrosion. Lead-acids should either be left sitting, or float-charged (held at a
constant voltage well below the gassing point).

 NiMH cells on the other hand will be damaged by prolonged trickle charge.
 Lithium ion cells however can not tolerate overcharging or overvoltage and the charge should

be terminated immediately when the upper voltage limit is reached.

Fast / Quick Charging

As the charging rate increases, so do the dangers of overcharging or overheating the

battery. Preventing the battery from overheating and terminating the charge when the

battery reaches full charge become much more critical. Each cell chemistry has its own

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