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THE 1985 CORVETTE DIY GUIDE - BATTERY/CHARGING SYSTEM
Battery/Charging System
BATTERY & CHARGING SYSTEM

NOTICE: While Corvsport.com has made every effort to ensure that the instruction provided on this site is both complete and accurate, it is presented here for REFERENCE ONLY.  All vehicle maintenance and repairs should only be performed by a qualified technician or mechanic and should not be attempted without the proper tools and/or experience.  Improperly performed vehicle repair can result in damage, injury, and even death.   User discretion is advised.

GENERAL ELECTRICAL SYSTEM DIAGNOSIS
The engine electrical system diagnosis includes the battery, the starter, and the generator/alternator (and related wiring.)  The following diagnosis charts will aid in troubleshooting system faults.  When a fault is traced to a particular component, refer to the corresponding system repairs as defined on this page.   Please utilize the links at the top of the page to find service instructions for each system.
BATTERY
A sealed battery is standard on all Corvettes.  There are no vent plugs in the cover.  The battery is completely sealed, except for two  small vent holes in the side.  These vent holes allow the small amount of gas produced in the battery to escape.  The battery has the following advantages over conventional batteries:
The battery has three major functions in the electrical system:

COMMON CAUSES OF FAILURE
The battery is not designed to last indefinitely.  However, with proper care, it will provide many years of service.  If the battery tests good but fails to perform satisfactorily in service for no apparent reason, the following are some of the more important factors that may point to the cause of trouble:

BUILT-IN HYDROMETER
The sealed battery has a built-in temperature compensated hydrometer in the top of the battery.  This hydrometer is to be used with the following diagnostic procedure.  When observing the hydrometer, make sure that the battery has a clean top.  A light my be needed in some poorly lit areas.
Under normal operation, two indications can be seen:
Occasionally, a third condition may appear:

DIAGNOSIS
The following procedure should be used for testing batteries:

1.) VISUAL INSPECTION
2.) HYDROMETER CHECK
3.) LOAD TEST
NOTE: Load testing may require the use of battery side terminal adapters to insure good connections.
BATTERY REPLACEMENT

BATTERY CHARGING
When it is necessary to charge the battery, the following safety precautions must be followed:




























CHARGING PROCEDURE

JUMP STARTING WITH AUXILIARY BATTERY (OR BOOSTER PACK)
NOTICE: Do not push or tow the vehicle to start.  damage to the emission system and/or to other parts of the vehicle may occur.  Also, both the booster pack (or auxiliary battery) and the discharged battery should be treated carefully when using jumper cables.  Follow the procedures outlined below.  Avoid producing sparks.

CAUTION:  Departure from the directions/conditions listed below could result in: 1.) Serious personal injury (particularly to the eyes) or property damage as the result of such causes as a battery explosion, battery acid, or electrical burns.  Additionally, damage to a battery (as those defined herein) may result in damage to other electronic components of both the vehicle being jump started as well as the car providing the jump (in instances where a battery to battery jump start is attempted.)

CHARGING SYSTEM
The basic charging system is the SI integral regulator charging system.  The generator used is a 17 SI type.  The 17 SI generators have delta stator windings and cannot be checked for opens.  The generator features a solid state regulator that is mounted inside the generator.  All regulator components are enclosed into a solid mold and this unit, along with the brush holder assembly, is attached to the slip ring end frame.  The regulator voltage setting cannot be adjusted. No periodic adjustments or maintenance of any kind is required on the entire generator assembly.
DIAGNOSIS
To avoid damage to your internally regulated generator, always follow these precautions:
Trouble in the charging system will show up as one or more of the following conditions:

UNDERCHARGED BATTERY
This condition, as demonstrated by slow cranking or a dark hydrometer can be caused by one or more of the following conditions (even though the indicator lamp may be operating normally.)  The following procedures also apply to cars with a voltmeter:
a.) Generator "BAT" terminal to ground.
b.) Generator No. 1 terminal to ground.
c.) Generator No. 2 terminal to ground.
If the above steps check satisfactorily, proceed to check the generator as follows:

OVERCHARGED BATTERY

NOTE:  There are a number of automotive/auto parts stores that provide free generator/alternator testing to their customers.  If you are inexperienced at performing the type of diagnostic work defined in this section, it is recommended that you utilize the services of one of these automotive facilities.
GENERATOR REMOVAL, INSTALLATION, and ON-CAR SERVICE

The generator does not require periodic lubrication.  The rotor shaft is mounted on ball bearings at the drive end and roller bearings at the slip ring end, and each contains a permanent grease supply.  At periodic intervals, check the mounting bolts for tightness and adjust the belt tension.

DISCLAIMER: While Corvsport.com makes every effort to ensure that this information is complete and accurate, you should always consult the manufacturer of your vehicle if you have a specific issue or question.
BACK TO 1985 CORVETTE DIY INDEX
TOPICS (Select One)
General Diagnosis
Battery
Common Problems
Battery Diagnosis
Battery Replacement
Battery Charging

Charging System
Charging Diagnosis
Generator Removal & Installation
1985 DIY Repairs --
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