Free Automotive Repair Advice by Certified ASE Technicians
How To Repair / Car Battery
Checking Battery and Charging System:
(always wear protective safety goggles and gloves before work begins)
Wear protective eye wear and clothing and remove all jewelry when checking
your battery and charging system. Jewelry is a good conductor of electricity and
is not recommended. Most batteries wear out every 3 to 5 years and need to be
replaced. Always replace your battery with an equal replacement battery to
assure proper operation. Automotive batteries have a +positive terminal (red), - negative terminal
(black). The battery in this illustration has a protective cover over the
positive terminal to prevent short circuit in case of an accident. Electricity
is stored in the battery and then supplied to the vehicle when the engine is not
running. While the engine is running the vehicles alternator charges the battery
for future use.
1. Checking Battery

To check a battery surface voltage remove the positive terminal protective
cover. Connect the +positive side meter lead (red) to the positive side battery
terminal. Connect the - negative (black) side meter lead to the negative battery
terminal. With the vehicle not running and the car sitting over night the
battery voltage should be between 12.5 and 12.8 volts.
2. Identify Alternator

The alternator is rotated by a drive belt driven by the vehicles engine while
it is running. Electrical voltage and amperage are generated to recharge the
battery and supply voltage to the electrical system of the car. The alternator
is held in place with mounting bolts. There is a main electrical wire on the
rear of the alternator that supplies voltage to a main voltage junction box. If
your alternator is not charging properly, your battery will slowly drain down
from operating all the electrical systems in your car and stop the car from
running.
3. Checking Alternator Output
+
Connect the voltage meter lead the same way you would in a battery static
voltage check, Start engine (do not drive) at engine idle the voltage should be
between 13.6 to 14.3 volts. If not the alternator may need replacing.
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The alternator provides electrical power to
the battery while the car is in operation. |
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The multi rib belt is the single drive belt that drives the auxiliary systems in your car like the alternator and air conditioning compressor. |
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The car battery stores electrical power in
reserve to be used at a later time. |
Common Problems:
1. alternator stops producing electrical power and the car stops because the battery dies.
2. battery fails do to age or defect.
3. battery cables become loose causing the electrical system to fail..
Also see:
Additional "How to" Car Repair or Services
1.How to Replace Air Filter
2.How to Change a Cabin filter
3.How to Change Oil and Filter
4.How to Tune Up with Throttle Bore Service
5.How to Replace a Radiator
6.How to Replace Fuel Filter
7.How to Read Trouble Codes
8.How Filters Work
9.How to Replace Front Brake Pads
10.How to Replace Rear Brake Pads
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