Common Dc Voltage Measurements; Automotive Batteries - Calterm 66430 Manual Del Propietário

4. Common DC Voltage Measurements

1) Set the function/range switch to the DC voltage range.
2) If the polarity of the circuit to be tested is known, touch
the black test lead to the neutral side. If the polarity is
unknown, touch the test leads to opposite sides of the
circuit. If the test leads are reversed, the "(-)" indicator will
appear on the display. Reverse the test leads for proper
polarity and read the value indicated on the display.

4.1 Automotive Batteries

Always wear safety goggles and gloves when
! WARNING
working near batteries.
Batteries contain sulfuric acid. Avoid contact with
! WARNING
clothing, skin, and eyes. If electrolyte comes in contact with
eyes, flush with water for at least 15 minutes and seek
immediate medical attention. If electrolyte comes in contact
with skin rinse it off immediately with water.
Batteries release hydrogen gas that is very
! WARNING
explosive. Keep sparks and flames away from battery and
never smoke while working with or near a battery.
Always disconnect the negative battery terminal
WARNING
!
first and reattach it last to prevent sparks.
Running an engine produces carbon
! WARNING
monoxide which can cause serious injury or death. Keep
the service area well ventilated or attach an exhaust gas
extraction system.
4.1a Battery Voltage Test
To remove the battery's surface charge and ensure an
accurate reading, turn the headlights on high for 15 seconds,
turn them off, then let the vehicle sit for a few minutes before
making the measurement. With the engine and all
accessories turned off, disconnect the battery's black (-)
negative cable. Next remove the red (+) positive battery
cable. For stubborn top post terminals use terminal puller
Calterm #30015 (available in your local auto parts store) to
remove terminals without damaging the posts. Use a terminal
and post cleaner such as Calterm #30009, 10, 11, or 12 to
remove oxidation and corrosion from the terminals and battery
posts or mounting surface. Battery anti-corrosion cleaner
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Calterm #30115 can be used to ensure a clean connection.
Set the function dial on the meter to the 20 volt DC setting.
Touch the negative (-) probe of the meter to the (-) negative
battery terminal and the (+) positive probe of the meter to the
(+) positive battery terminal. The display should read at least
12.4 volts on a 12 volt DC battery. If it reads less than 12.4
volts the battery should be charged before proceeding with
any other tests.
Slip chemically treated anti-corrosion washers Calterm #30098
between the battery and the battery cable terminals prior to
reinstalling the cables to prevent future corrosion. Reinstall
and tighten the positive (+) cable first. Next reinstall and
tighten the negative (-) battery cable.
4.1b Running Voltage Test
This test provides a quick indication of whether the charging
system is functioning properly.
Use caution not to contact cooling fan or belts as
WARNING
!
serious personal injury may result. Always fully engage the
parking brake and place the automatic transaxle in P (Park) or
manual transaxle in N (Neutral) before performing tests with
the engine running.
Start the engine, and increase the RPM to approximately
2000. Set the function dial on the meter to 20V DC. Check
the battery voltage by touching the negative (-) probe of the
meter to the negative (-) battery terminal and the positive (+)
probe of the meter to the positive (+) battery terminal. With
the engine running the battery voltage should be between
14-15 volts. If the voltage is over 15 volts there may be a
problem with the voltage regulator. See a troubleshooting
manual specific to your vehicle for additional information.
4.1c Cranking Voltage Test
This test provides a fast overall check of the starting system.
Use caution not to contact cooling fan or belts as
WARNING
!
serious personal injury may result. Always fully engage the
parking brake and place the automatic transaxle in P (Park) or
manual transaxle in N (Neutral) before performing tests with
the engine running.
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